Energy Conservation Program: Test Procedure for Circulator Pumps

Federal RegisterSep 19, 2022

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DEPARTMENT OF ENERGY

10 CFR Parts 429 and 431

[EERE-2016-BT-TP-0033]

RIN 1904-AD77

Energy Conservation Program: Test Procedure for Circulator Pumps

AGENCY:

Office of Energy Efficiency and Renewable Energy, Department of Energy.

ACTION:

Final rule.

SUMMARY:

The U.S. Department of Energy (“DOE”) is establishing definitions, a test procedure, sampling and rating requirements, and enforcement provisions for circulator pumps. Currently, circulator pumps are not subject to DOE test procedures or energy conservation standards. DOE is adopting a test procedure for measuring the circulator energy index for circulator pumps. The test method references the relevant industry test standard. The definitions and test procedures are based on the recommendations of the Circulator Pump Working Group, which was established under the Appliance Standards Rulemaking Federal Advisory Committee.

DATES:

The effective date of this rule is October 19, 2022. Compliance with the final rule will be mandatory for representations of head, flow rate, driver power input, circulator energy rating, and circulator energy index made on or after March 20, 2023. The incorporation by reference of certain publications listed in the rule is approved by the Director of the Federal Register on October 19, 2022.

ADDRESSES:

The docket, which includes

Federal Register

notices, public meeting attendee lists and transcripts, comments, and other supporting documents/materials, is available for review at

www.regulations.gov

. All documents in the docket are listed in the

www.regulations.gov

index. However, some documents listed in the index, such as those containing information that is exempt from public disclosure, may not be publicly available.

A link to the docket web page can be found at

www.regulations.gov/docket/EERE-2016-BT-STD-0004

. The docket web page contains instructions on how to access all documents, including public comments, in the docket.

For further information on how to review the docket contact the Appliance and Equipment Standards Program staff at (202) 287-1445 or by email:

ApplianceStandardsQuestions@ee.doe.gov

FOR FURTHER INFORMATION CONTACT:

Mr. Jeremy Dommu, U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Building Technologies Office, EE-2J, 1000 Independence Avenue SW, Washington, DC 20585-0121. Telephone: (202) 586-9870. Email:

ApplianceStandards Questions@ee.doe.gov

Ms. Amelia Whiting, U.S. Department of Energy, Office of the General Counsel, GC-33, 1000 Independence Avenue SW, Washington, DC, 20585-0121. Telephone: 202-586-2588. Email:

Amelia.Whiting@hq.doe.gov

SUPPLEMENTARY INFORMATION:

DOE incorporates by reference the following industry standards into 10 CFR part 431:

HI 40.6-2021, “Methods for Rotodynamic Pump Efficiency Testing”.

HI 41.5-2022 “Hydraulic Institute Program Guideline for Circulator Pump Energy Rating Program”.

Copies of HI 40.6-2021 and HI 41.5-2022 can be obtained from the Hydraulic Institute (“HI”) at 6 Campus Drive, First Floor North, Parsippany, NJ 07054-4406, (973) 267-9700, or by going to

www.pumps.org

For a further discussion of these standards, see section IV.N of this document.

Table of Contents

I. Authority and Background

A. Authority

B. Background

II. Synopsis of the Final Rule

III. Discussion

A. General Comments

B. Scope and Definitions

1. CPWG Recommendations

2. Definition of Circulator Pump

3. Definition of Circulator Pump Varieties

4. Definition of Circulator-Less-Volute and Header Pump

5. Definition of On-Demand Circulator Pumps

6. Applicability of Test Procedure Based on Pump Configurations

7. Basic Model

C. Rating Metric

D. Test Methods for Different Circulator Pump Categories and Control Varieties

1. Definitions Related to Circulator Pump Control Varieties

2. Reference System Curve

3. Pressure Control

4. Temperature Control

5. Manual Speed Control

6. External Input Signal Control

7. No Controls or Full Speed Test

E. Determination of Circulator Pump Performance

1. Incorporation by Reference of HI 40.6-2021

2. Exceptions, Modifications and Additions to HI 40.6-2021

3. Calculation and Rounding Modifications and Additions

4. Rated Hydraulic Horsepower

F. Sampling Plan and Enforcement Provisions for Circulator Pumps

1. Sampling Plan

2. Enforcement Provisions

G. Representations of Energy Use and Energy Efficiency

H. Test Procedure Costs and Harmonization

1. Test Procedure Costs and Impacts

2. Harmonization With Industry Standards

I. Compliance Date

IV. Procedural Issues and Regulatory Review

A. Review Under Executive Orders 12866 and 13563

B. Review Under the Regulatory Flexibility Act

C. Review Under the Paperwork Reduction Act of 1995

D. Review Under the National Environmental Policy Act of 1969

E. Review Under Executive Order 13132

F. Review Under Executive Order 12988

G. Review Under the Unfunded Mandates Reform Act of 1995

H. Review Under the Treasury and General Government Appropriations Act, 1999

I. Review Under Executive Order 12630

J. Review Under Treasury and General Government Appropriations Act, 2001

K. Review Under Executive Order 13211

L. Review Under Section 32 of the Federal Energy Administration Act of 1974

M. Congressional Notification

N. Description of Materials Incorporated by Reference

V. Approval of the Office of the Secretary

I. Authority and Background

Pumps are included in the list of “covered equipment” for which DOE is authorized to establish and amend energy conservation standards and test procedures. (42 U.S.C. 6311(1)(A)) Circulator pumps, which are the subject of this final rule, are a category of pumps. Circulator pumps generally are designed to circulate water in commercial and residential applications. Circulator pumps do not include dedicated-purpose pool pumps, for which test procedures and energy conservation standards are established in title 10 of the Code of Federal Regulations (“CFR”) part 431 subpart Y. DOE has not previously established test procedures or energy conservation standards applicable to circulator pumps. The following sections discuss DOE's authority to establish test procedures for circulator pumps and relevant background information regarding DOE's consideration of test procedures for this equipment.

A. Authority

The Energy Policy and Conservation Act, as amended (“EPCA”),

authorizes DOE to regulate the energy efficiency of a number of consumer products and certain industrial equipment. (42 U.S.C. 6291-6317) Title III, Part C

of EPCA, added by Public Law 96-619, Title IV, section 441(a) (42 U.S.C. 6311-6317 as codified) established the Energy Conservation Program for Certain Industrial Equipment, which sets forth a variety of provisions designed to improve energy efficiency. This equipment includes pumps, the subject of this document. (42 U.S.C. 6311(1)(A))

All references to EPCA in this document refer to the statute as amended through the Energy Act of 2020, Public Law 116-260 (Dec. 27, 2020), which reflect the last statutory amendments that impact Parts A and A-1 of EPCA.

For editorial reasons, upon codification in the U.S. Code, Part B was redesignated Part A.

The energy conservation program under EPCA consists essentially of four parts: (1) testing, (2) labeling, (3) Federal energy conservation standards, and (4) certification and enforcement procedures. Relevant provisions of EPCA specifically include definitions (42 U.S.C. 6311), test procedures (42 U.S.C. 6314), labeling provisions (42 U.S.C. 6315), energy conservation standards (42 U.S.C. 6313), and the authority to require information and reports from manufacturers (42 U.S.C. 6316; 42 U.S.C. 6296).

The Federal testing requirements consist of test procedures that manufacturers of covered equipment must use as the basis for: (1) certifying to DOE that their equipment complies with the applicable energy conservation standards adopted pursuant to EPCA (42 U.S.C. 6316(a); 42 U.S.C. 6295(s)), and (2) making other representations about the efficiency of that equipment (42 U.S.C. 6314(d)). Similarly, DOE must use these test procedures to determine whether the equipment complies with relevant standards promulgated under EPCA. (42 U.S.C. 6316(a); 42 U.S.C. 6295(s))

Federal energy efficiency requirements for covered equipment established under EPCA generally supersede State laws and regulations concerning energy conservation testing, labeling, and standards. (42 U.S.C. 6316(a) and 42 U.S.C. 6316(b); 42 U.S.C. 6297) DOE may, however, grant waivers of Federal preemption for particular State laws or regulations, in accordance with the procedures and other provisions of EPCA. (42 U.S.C. 6316(b)(2)(D))

Under 42 U.S.C. 6314, EPCA sets forth the criteria and procedures DOE must follow when prescribing or amending test procedures for covered products. EPCA requires that any test procedures prescribed or amended under this section must be reasonably designed to produce test results which reflect energy efficiency, energy use or estimated annual operating cost of a type of covered equipment during a representative average use cycle (as determined by the Secretary) and requires that test procedures not be unduly burdensome to conduct. (42 U.S.C. 6314(a)(2))

Before prescribing any final test procedures, the Secretary must publish proposed test procedures in the

Federal Register

and afford interested persons an opportunity (of not less than 45 days' duration) to present oral and written data, views, and arguments on the proposed test procedures. (42 U.S.C. 6314(b)).

DOE is publishing this final rule in accordance with the statutory authority in EPCA.

B. Background

As stated previously in this document, EPCA includes “pumps” among the industrial equipment listed as “covered equipment” for the purpose of Part A-1, although EPCA does not define the term “pump.” (42 U.S.C. 6311(1)(A)) In a final rule published January 25, 2016, DOE established a definition for “pump,” associated definitions, and test procedures for certain pumps. 81 FR 4086 (“January 2016 TP final rule”). “Pump” is defined as equipment designed to move liquids (which may include entrained gases, free solids, and totally dissolved solids) by physical or mechanical action and includes a bare pump and, if included by the manufacturer at the time of sale, mechanical equipment, driver, and controls. 81 FR 4086, 4147; 10 CFR 431.462. Circulator pumps fall within the scope of this definition.

While DOE has defined “pump” broadly, the test procedure established in the January 2016 TP final rule is applicable only to certain categories of clean water pumps,

specifically those that are end suction close-coupled (“ESCC”); end suction frame mounted/own bearings (“ESFM”); in-line (“IL”); radially split, multi-stage, vertical, in-line casing diffuser (“RSV”); and submersible turbine (“ST”) pumps with the following characteristics:

A “clean water pump” is a pump that is designed for use in pumping water with a maximum non-absorbent free solid content of 0.016 pounds per cubic foot, and with a maximum dissolved solid content of 3.1 pounds per cubic foot, provided that the total gas content of the water does not exceed the saturation volume and disregarding any additives necessary to prevent the water from freezing at a minimum of 14 °F. 10 CFR 431.462.

• Flow rate of 25 gallons per minute (“gpm”) or greater at best efficiency point (“BEP”) at full impeller diameter;

• 459 feet of head maximum at BEP at full impeller diameter and the number of stages specified for testing;

• design temperature range from 14 to 248 °F;

• designed to operate with either: (1) a 2- or 4-pole induction motor, or (2) a non-induction motor with a speed of rotation operating range that includes speeds of rotation between 2,880 and 4,320 revolutions per minute (“rpm”) and/or 1,440 and 2,160 rpm, and in either case, the driver and impeller must rotate at the same speed;

• 6-inch or smaller bowl diameter for ST pumps;

• A specific speed less than or equal to 5,000, when calculated using U.S. customary units, for ESCC and ESFM pumps;

• Except for: fire pumps; self-priming pumps; prime-assist pumps; magnet driven pumps; pumps designed to be used in a nuclear facility subject to 10 CFR part 50, “Domestic Licensing of Production and Utilization Facilities”; and pumps meeting the design and construction requirements set forth in any relevant military specifications.

E.g., MIL-P-17639F, “Pumps, Centrifugal, Miscellaneous Service, Naval Shipboard Use” (as amended); MIL-P-17881D, “Pumps, Centrifugal, Boiler Feed, (Multi-Stage)” (as amended); MIL-P-17840C, “Pumps, Centrifugal, Close-Coupled, Navy Standard (For Surface Ship Application)” (as amended); MIL-P-18682D, “Pump, Centrifugal, Main Condenser Circulating, Naval Shipboard” (as amended); and MIL-P-18472G, “Pumps, Centrifugal, Condensate, Feed Booster, Waste Heat Boiler, And Distilling Plant” (as amended). Military specifications and standards are available at

https://everyspec.com/MIL-SPECS

10 CFR 431.464(a)(1); 81 FR 4086, 4148. The pump categories subject to the current test procedures are referred to as “general pumps” in this document. As stated, circulator pumps are not general pumps and therefore, are not subject to the current pumps test procedure.

DOE also published a final rule establishing energy conservation standards applicable to certain classes of general pumps. 81 FR 4368 (Jan. 26, 2016) (“January 2016 ECS final rule”);

see also

10 CFR 431.462. DOE recognized circulator pumps as a category of pumps, but DOE did not define “circulator pump.” 81 FR 4086, 4097.

In this final rule, DOE is establishing a definition of circulator pump, associated definitions for categories of circulator pumps, as well as related definitions for control varieties of circulator pumps (see sections III.B.2, III.B.3, III.B.4, III.B.5 and III.D.1 of this final rule). These definitions are necessary to establish the scope of applicability of the circulator pump test procedure. The scope of the test procedure is discussed in section III.B.6 of this document.

1. CPWG Recommendations

The September 2016 Circulator Pump Recommendations addressed the scope of a circulator pumps rulemaking. Specifically, the CPWG recommended that the scope of a circulator pumps test procedure and energy conservation standards cover clean water pumps (as defined at 10 CFR 431.462) distributed in commerce with or without a volute

and that are one of the following categories: wet rotor circulator pumps, dry rotor close-coupled circulator pumps, and dry rotor mechanically-coupled circulator pumps. The CPWG also recommended that the scope exclude submersible pumps and header pumps. 86 FR 24516, 24520; (Docket No. EERE-2016-BT-STD-0004, No. 58, Recommendations #1A, 2A and 2B at pp. 1-2) The CPWG also recommended several definitions relevant to scope, see discussion in sections III.B.3 through III.B.5. 86 FR 24516, 24520; (Docket No. EERE-2016-STD-0004, No. 58, Recommendation #2B, 3A, and 3B at pp. 2-3)

Volutes are also sometimes referred to as a “housing” or “casing.”

DOE notes that generally these definitions recommended by the CPWG rely on terms previously defined in the January 2016 TP final rule, including “close-coupled pump,” “mechanically-coupled pump,” “dry rotor pump,” “single axis flow pump,” and “rotodynamic pump.” 81 FR 4086, 4146-4147; 10 CFR 431.462. In addition, the recommended definition for submersible pump is the same as that already defined in a 2017 test procedure final rule for dedicated-purpose pool pumps (“DPPP”) (“August 2017 DPPP TP final rule”). 82 FR 36858, 36922 (August 7, 2017); 10 CFR 431.462.

DOE discusses the definitions of wet rotor circulator pump; dry rotor, two-

piece circulator pump; dry rotor, three-piece circulator pump; and horizontal motor in section III.B.3, header pump in section III.B.4, and submersible pump in section III.B.6 of this final rule.

2. Definition of Circulator Pump

In the December 2021 NOPR, DOE proposed a definition of circulator pump at 10 CFR 431.462 consistent with the definition recommended by the CPWG and informed by the standard American National Standards Institute (“ANSI”)/HI 1.1-1.2-2014 standard (“ANSI/HI 1.1-1.2-2014”), “Rotodynamic Centrifugal Pumps for Nomenclature and Definitions.” 86 FR 72096, 72101-72102. Specifically, DOE proposed the following definition for circulator pump:

Circulator pump

is a pump that is either a wet rotor circulator pump; a dry rotor, two-piece circulator pump; or a dry rotor, three-piece circulator pump. A circulator pump may be distributed in commerce with or without a volute.

Id.

at 86 FR 72102.

DOE requested comment on the proposed definition for circulator pump.

Id.

In response to the December 2021 NOPR, HI, Grundfos, NEEA, and NYSERDA agreed with the proposed definition of circulator pumps. (HI, No. 9 at p. 3; Grundfos, No. 7 at p. 1; NEEA, No. 11 at p. 2; NYSERDA, No. 6 at p. 1)

For the reasons discussed in the December 2021 NOPR and in the preceding paragraphs, in this final rule, DOE adopts the definition of circulator pump as proposed in the December 2021 NOPR.

The definitions of the pump categories that comprise the scope of “circulator pump” are addressed in the following section.

3. Definition of Circulator Pump Varieties

In the December 2021 NOPR, DOE proposed to adopt definitions for wet rotor circulator pump; dry rotor, two-piece circulator pump; and dry rotor, three-piece circulator pump at 10 CFR 431.462 as recommended by the CPWG and supported by stakeholder comments in response to the May 2021 RFI. 86 FR 72096, 72102. The proposed definitions are as follows:

Wet rotor circulator pump

means a single stage, rotodynamic, close-coupled, wet rotor pump. Examples include, but are not limited to, pumps generally referred to in industry as CP1.

Dry rotor, two-piece circulator pump

means a single stage, rotodynamic, single-axis flow, close-coupled, dry rotor pump that:

(1) Has a rated hydraulic power less than or equal to five horsepower at best efficiency point at full impeller diameter,

(2) Is distributed in commerce with a horizontal motor, and

(3) Discharges the pumped liquid through a volute in a plane perpendicular to the shaft. Examples include, but are not limited to, pumps generally referred to in industry as CP2.

Dry rotor, three-piece circulator pump

means a single stage, rotodynamic, single-axis flow, mechanically-coupled, dry rotor pump that:

(1) Has a hydraulic power less than or equal to five horsepower at best efficiency point at full impeller diameter,

(2) Is distributed in commerce with a horizontal motor, and

(3) Discharges the pumped liquid through a volute in a plane perpendicular to the shaft. Examples include, but are not limited to, pumps generally referred to in industry as CP3.

Id.

at 86 FR 72139.

In the December 2021 NOPR, DOE also proposed a definition for horizontal motor, consistent with the intent of the CPWG:

Horizontal motor

means a motor, for which the motor shaft position when functioning under operating conditions specified in manufacturer literature, includes a horizontal position.

Id.

at 86 FR 72102.

DOE tentatively concluded that the proposed modification to the horizontal motor definition would provide additional specificity but would not in practice change the pumps currently excluded from the IL pump definition (and now proposed to be included in the circulator pump definition) through use of the term.

Id.

DOE requested comment on the proposed definition for horizontal motor, including whether it met the intent of the CPWG recommendation or whether it would include other motors not intended to be captured in the definition.

Id.

NYSERDA supported the definitions of wet rotor circulator pump; dry rotor, two-piece circulator pump; dry rotor, three-piece circulator pump; and horizontal motor, as recommended by the CPWG. (NYSERDA, No. 6 at pp. 1-2) HI and Grundfos agreed with the proposed definition of horizontal motor and stated that it meets the intent of the CPWG. (HI, No. 9 at p. 3; Grundfos, No. 7 at p. 1) NEEA agreed also with the proposed definition of horizontal motor and stated the definition was consistent with the intent of CPWG. (NEEA, No. 11 at p. 2)

For the reasons discussed in the December 2021 NOPR and in the preceding paragraphs, in this final rule, DOE adopts the definitions of wet rotor circulator pump; dry rotor, two-piece circulator pump; dry rotor, three-piece circulator pump; and horizontal motor as proposed in the December 2021 NOPR.

4. Definition of Circulator-Less-Volute and Header Pump

In the December 2021 NOPR, DOE discussed that some circulator pumps are distributed in commerce as a complete assembly with a motor, impeller, and volute, while other circulator pumps are distributed in commerce with a motor and impeller, but without a volute (herein referred to as “circulators-less-volute”). Some circulators-less-volute are solely intended to be installed in other equipment, such as a boiler, using a cast piece in the other piece of equipment as the volute, while others can be installed as a replacement for a failed circulator pump in an existing system or newly installed with a paired volute in the field. 86 FR 72096, 72102; (Docket No. EERE-2016-BT-STD-0004, No. 47 at pp. 371-372; Docket No. EERE-2016-BT-STD-0004, No. 70 at p. 99) The CPWG recommended excluding circulator pumps that are distributed in commerce exclusively to be incorporated into other OEM equipment, such as boilers or pool heaters. 86 FR 72096, 72103; (Docket No. EERE-2016-BT-STD-0004, No. 74 at pp. 413-416)

As stated in the December 2021 NOPR, the CPWG suggested referring to circulator-less-volute that are intended solely for installation in another piece of equipment and do not have a paired volute that is distributed in commerce as “header pumps,” and recommended defining header pump as pump that consists of a circulator-less-volute intended to be installed in an [original equipment manufacturer] “OEM” piece of equipment that serves as the volute. 86 FR 72096, 72103; (Docket No. EERE-2016-BT-STD-0004, No. 74 at pp. 384-386; No. 58 Recommendation #2B at p. 2)

The CPWG recommended that for header pumps distributed in commerce with regulated equipment, DOE should consider modifying the test procedure and metric for such regulated equipment during the next round of applicable rulemakings to account for the energy use of header pumps in a modified metric. For header pumps distributed in commerce with non-regulated equipment, the CPWG recommended that DOE should consider

test procedures and standards for such pumps or equipment at a later date. (Docket No. EERE-2016-BT-STD-0004, No. 58 Non-Binding Recommendation to the Secretary #2 at p. 10); 86 FR 72096, 72103.

In the December 2021 NOPR, DOE tentatively agreed that a circulator-less-volute designed solely for use as a component in a separate piece of equipment should be distinguished from a circulator-less-volute generally. To provide a distinction between a circulator-less-volute and a header pump, DOE proposed to add additional detail within the definition of header pump recommended by the CPWG and to add a definition of circulator-less-volute to be mutually exclusive from the definition of a header pump. These definitions proposed by DOE are as follows:

Header pump

means a circulator pump distributed in commerce without a volute and for which a paired volute is not distributed in commerce. Whether a paired volute is distributed in commerce will be determined based on published data, marketing literature, and other publicly available information.

Circulator-less-volute

means a circulator pump distributed in commerce without a volute and for which a paired volute is also distributed in commerce. Whether a paired volute is distributed in commerce will be determined based on published data, marketing literature, and other publicly available information.

86 FR 72096, 72103.

DOE requested comment on the proposed definitions of header pump and circulator-less-volute.

Id.

DOE also tentatively concluded that requiring testing of header pumps using a reference volute, as required in EU Regulation No 622/2012, may result in a rating that is not representative of its energy use in the equipment for which it is designed, and that assessing header pump energy use within broader equipment categories in which they are embedded, such as boilers, may be more appropriate. As such, DOE did not propose to include header pumps in the scope of the test procedure, nor did it propose a test method for them.

Id.

In response to the December 2021 NOPR, NYSERDA supported the definition of header pump as recommended by the CPWG. (NYSERDA, No. 6 at p. 2) HI and NEEA agreed with the proposed definitions of header pump and circulator-less-volute. (HI, No. 9 at p. 3; NEEA, No. 11 at p. 2)

Grundfos agreed with the proposed definition of circulator-less-volute but stated that header pumps should be included in this definition and covered by the circulator-less-volute testing requirements. (Grundfos, No. 7 at p. 1) Additionally, Grundfos noted that the CPWG's basis for excluding header pumps was because an OEM specific volute was not available for testing. Grundfos commented that header pumps are generally the same as standard circulator-less-volutes in the market and that representative volutes already exist or can be created by manufacturers. Grundfos stated that DOE should require that header pumps be tested like circulators-less-volute, except that the manufacturer determines the volute to be used and make this volute available for testing on the open market so that all interested parties can purchase and test the pump in the same manner it was certified. Grundfos noted that allowing header pumps to exist on the market without testing creates a loophole that can be exploited to avoid meeting the test standard and efficiency standard requirements. (Grundfos, No. 7 at p. 4)

While Grundfos has suggested a method for testing header pumps, DOE observes that the suggested method would increase burden on manufacturers by requiring creation of volutes that may not be used in commerce (given that header pumps are intended solely for installation in another piece of equipment) and requiring them to be available for testing on the open market. Additionally, by requiring testing with volutes for which the application is only for equipment testing, the suggested method would not be representative of an average use. Grundfos did not address DOE's tentative determination regarding lack of representativeness of testing header pumps with reference volutes. As such, in this final rule, DOE adopts the definitions of header pump and circulator-less-volute as proposed in the December 2021 NOPR and is not including header pumps within the scope of the test procedure nor adopting a test method for header pumps.

5. Definition of On-Demand Circulator Pumps

In the December 2021 NOPR, DOE stated that on-demand circulator pumps are designed to maintain hot water supply within a temperature range by activating in response to a signal, such as user presence. 86 FR 72096, 72104. Discussion during CPWG meetings suggested that the purpose of recommending a definition for on-demand circulator pumps would be to allow for the possibility of considering them as a separate equipment class with a different standard level, while still applying the metric and test procedure to them. (Docket No. EERE-2016-BT-STD-0004-0069, p. 199)

The CPWG discussed that on-demand controls do not reduce the speed of the pump, but rather reduce the hours of use. Pumps with on-demand controls could also have speed controls, which the recommended metric would capture. (Docket No. EERE-2016-BT-STD-0004-0069, pp. 172-173) In addition, CPWG members discussed that the extent to which time-based controls are used is unknown (

Id.

at p. 176), and that rather than attempting to capture it in the metric, utility programs could consider prescriptive rebates associated with these controls. (

Id.

at p. 178) In addition, CPWG members suggested that legionella concerns would limit the application of on-demand controls.

(

Id.

at pp. 195-196)

As discussed in the transcript, situations where water is stagnant and the temperature drops can result in growth of legionella.

DOE notes that neither HI 41.5-2021 nor HI 41.5-2022 address on-demand circulator pumps. DOE proposed to define on-demand circulator pump at 10 CFR 431.462 consistent with the definition recommended by the CPWG, as follows:

On-demand circulator pump

means a circulator pump that is distributed in commerce with an integral control that:

• Initiates water circulation based on receiving a signal from the action of a user [of a fixture or appliance] or sensing the presence of a user of a fixture and cannot initiate water circulation based on other inputs, such as water temperature or a pre-set schedule.

• Automatically terminates water circulation once hot water has reached the pump or desired fixture.

• Does not allow the pump to operate when the temperature in the pipe exceeds 104 °F or for more than 5 minutes continuously.

86 FR 72096, 72104.

DOE did not propose to exclude on-demand circulator pumps from the scope of the test procedure or to develop a credit for such controls in the December 2021 NOPR. DOE noted that if on-demand circulator pumps are equipped with other controls that reduce speed, they may be tested according to the relevant test methods rather than using the no controls test.

Id.

DOE stated that it would consider whether standards were appropriate for this equipment in a future energy conservation standards rulemaking.

Id.

DOE requested comment on its proposal to include on-demand circulator pumps within the scope of

this test procedure. DOE also requested data and information that would justify a CEI credit for on-demand circulator pumps. 86 FR 72096, 72104.

Joint Advocates supported inclusion of on-demand controls but noted that the energy savings benefits of reduced run time would not be directly captured by the test procedure. Joint Advocates explained that on-demand controls have the potential to reduce energy consumption in water recirculation applications. Joint Advocates encouraged DOE to consider options to promote the adoption of on-demand controls that reduce energy consumption by reducing circulator pump run-time. (Joint Advocates, No. 8 at p. 3)

CA IOUs supported DOE's proposed definition of the on-demand circulator pump product class, in particular that a product must be exclusively an on-demand circulator and should not support additional control modes typical of other circulator products (

e.g.,

constant pressure), or support bypass functionality, ensuring that users receive consistent run-hour reduction benefits relative to conventional products. (CA IOUs, No. 10 at p. 2) CA IOUs stated they aim to encourage widespread market adoption in the domestic hot water sector, in part by maintaining the cost benefit to consumers of this product. CA IOUs included an analysis of potential costs and benefits to a consumer when applying a 1.0 CEI requirement, which would imply an electrically commutated motor (“ECM”). CA IOUs stated that, based on their analysis, cost is the largest influencing factor of consumer payback, followed by runtime hours, with CEI as the least influential factor.

Based on this, CA IOUs encouraged DOE to develop a methodology for on-demand circulator products that does not require the ECM level unless lifecycle cost effectiveness can be demonstrated. (CA IOUs, No. 10 at pp. 3-5). CA IOUs stated that baseline operating hours of a domestic hot water circulator product is 6,400 hours per year and the on-demand product is instead 92, a ratio of 0.014. CA IOUs encouraged DOE to develop a CEI score for circulator products that demonstrates the substantial energy savings available and allows for field representative lifecycle cost-benefit calculations. (CA IOUs, No. 10 at p. 5)

CA IOUs also included a discussion regarding potential economics for consumers with electric water heaters versus natural gas water heaters.

NEEA recommended that DOE require testing circulator pumps at full speed but provide a CEI credit for circulator pumps intended for domestic hot water recirculation equipped with run-hour controls. NEEA stated that eliminating unnecessary operation at no cost of convenience or performance to customers, is the most significant method to reduce circulator energy consumption. NEAA added that ignoring this factor misses an important opportunity for energy conservation and fails to communicate energy savings to the market. NEEA commented that a CEI credit is the most effective strategy to convey this factor to consumers. (NEEA, No. 11 at pp. 1-2)

Additionally, NEEA stated that efficient run hour controls include temperature (

i.e.,

aquastat), on-demand, learning, or a combination of timer and temperature run-hour controls. NEEA noted that the Regional Technical Forum's circulator measure workbook contains calculations about the potential energy savings from run-hour controls on domestic hot water circulators, and that according to this analysis, run-hour controls reduce energy consumption by 50 percent to 99 percent. NEEA stated that the CEI credit should accurately reflect the energy savings reduction from each control type. However, NEEA commented that savings from learning-based controls are less well-proven in the field, and that there is concern that timer-based controls can be overridden or set to a high number of hours to avoid homeowner complaints. But NEEA noted also that their research indicates that timer-controls are relatively consistently applied. (NEEA, No. 11 at p. 4) NEEA suggested that there should be different CEI credits for different control types, especially on-demand and temperature-based, due to differences between commercial and residential applications. (NEEA, No. 11 at pp. 4-5)

NEEA recommended that rating equipment with applicable run hours controls should be optional so as to represent an opportunity rather than a burden, especially for manufacturers of equipment with on-demand controls that cannot operate without them, to potentially comply with future standards without redesigning the motor. NEEA stated that circulators that can only be operated with on-demand controls represent a small portion of the market but are very efficient due to extremely low run hours and increasing the efficiency of the pump and motor would likely not be cost effective. NEEA stated that an appropriate CEI credit could allow such equipment to remain on the market at a cost-competitive price point, which may increase their adoption and lead to more overall pump and hot water savings. (NEEA, No. 11 at p. 5)

NEEA stated that in order for the CEI credit to not represent a loophole in the standard, DOE must calibrate the credit to ensure it provides a comparable and meaningful metric compared to the hydronic heating controls currently proposed in the test procedure, and require rating with the most consumptive control available, such that the mere availability of run-hour controls (or other efficient controls) do not circumvent the desired efficiency of the standard. NEEA suggested that DOE consider the relative run hours of hydronic heating versus domestic hot water installations, as temperature-based run-hour controls may run a similar number of hours as hydronic heating controls and a significant credit may not be warranted. (

Id.

)

NEEA noted that the CEI credit concept was not discussed in the CPWG nor approved in the term sheet, and that an appropriate credit and certification system may take time to develop and implement. NEEA stated that, while DOE could make a reasonable proposal now, the addition of special treatment for run-hours-controls-equipped circulators could be considered in the future with more opportunity for discussion and input. In this case, NEEA recommended that on demand circulators not be exempted and be covered by the applicable test procedure and any future standard to provide consistency for manufacturers and the market. (NEEA, No. 11 at p. 5)

HI agreed with the proposed definition of on-demand circulator pump and inclusion of on-demand circulating pump within the scope of the test procedure. However, HI stated that domestic hot water circulators come with several intermittent control methods, including temperature and timer, that all provide reduced energy consumption versus a circulator under continuous operation. HI stated that as DOE only identified on-demand controls in the December 2021 NOPR, DOE should not consider credits for them. HI stated that in future rulemakings DOE should consider creating a category and test procedure calculations for intermittent controlled domestic hot water circulator pumps that define an average use case for this new category of pumps, including operating hours and load points. (HI, No. 9 at p. 3) Grundfos stated that inclusion of on-demand circulator pumps is warranted but commented similarly to HI regarding the other control methods that were not included, recommending that these categories should be included in a separate rulemaking. (Grundfos, No. 7 at p. 1)

After reviewing and considering all the comments on on-demand circulator pumps, DOE is adopting a definition for on-demand circulator pumps and a scope of applicability for the test procedure that includes on-demand circulator pumps, as proposed. DOE is not adopting a CEI credit for on-demand circulators in this rulemaking. Such a credit was not discussed by the CPWG, nor proposed in the NOPR. As noted by the commenters, development of further information as to the prevalence, variety, and operation of on-demand controls is likely needed. Accordingly, DOE is not addressing a CEI credit for on-demand circulator pumps in this final rule. In response to the comments from CA IOUs and NEEA, DOE will consider the appropriate scope and product categories for standards for on-demand circulators in a separate energy conservation rulemaking.

6. Applicability of Test Procedure Based on Pump Configurations

In the December 2021 NOPR, DOE proposed that the test procedure would be applicable to circulator pumps that are clean water pumps, including circulators-less-volute and on-demand circulator pumps, and excluding header pumps and submersible pumps (as recommended by the CPWG). DOE requested comment on the proposed scope. 86 FR 72096, 72105.

NEEA agreed with the proposed scope of applicability. (NEEA, No. 11 at p. 2) NYSERDA supported the proposed test procedure scope, specifically as limited to clean water pumps, consistent with the scope of general pumps. (NYSERDA, No. 6 at p. 2) HI agreed with the proposed scope of applicability to exclude header pumps and submersible pumps but include circulator-less-volute pumps. (HI, No. 9 at p. 4) Joint Advocates supported exclusion of header pumps. (Joint Advocates, No. 8 at p. 1)

Grundfos agreed that submersible pumps should be excluded but stated that header pumps should be included. (Grundfos, No. 7 at p. 1)

As discussed in section III.B.4 of this document, DOE continues to have concerns about the representativeness of including header pumps in the scope of the test procedure and, therefore, is not including them in scope.

For the reasons discussed in the December 2021 NOPR and in the preceding paragraphs, in this final rule, DOE is adopting the scope as proposed in the December 2021 NOPR.

7. Basic Model

In the course of regulating consumer products and commercial and industrial equipment, DOE has developed the concept of a “basic model” to determine the specific product or equipment configuration(s) to which the regulations would apply. For the purposes of applying the proposed circulator pump regulations, DOE proposed to rely on the definition of “basic model” as currently defined at 10 CFR 431.462. 86 FR 72096, 72105. DOE stated that application of the current definition of “basic model” would allow manufacturers of circulator pumps to group similar models within a basic model to minimize testing burden, while ensuring that key variables that differentiate circulator pump energy performance or utility are maintained as separate basic models.

Id.

As proposed, manufacturers would be required to test only a representative number of units of a basic model in lieu of testing every model they manufacture.

Id.

As proposed, individual models of circulator pumps would be permitted to be grouped under a single basic model, so long as all grouped models have the same representative energy performance, which is representative of the least efficient or most consumptive unit.

Id.

Specifically, for pumps, DOE's existing definition of basic model is as follows:

Basic model

means all units of a given class of pump manufactured by one manufacturer, having the same primary energy source, and having essentially identical electrical, physical, and functional (or hydraulic) characteristics that affect energy consumption, energy efficiency, water consumption, or water efficiency; and, in addition, for pumps that are subject to the standards specified in 10 CFR 431.465(b), the following provisions also apply:

(1) All variations in numbers of stages of bare RSV and ST pumps must be considered a single basic model;

(2) Pump models for which the bare pump differs in impeller diameter, or impeller trim, may be considered a single basic model; and

(3) Pump models for which the bare pump differs in number of stages or impeller diameter, and which are sold with motors (or motors and controls) of varying horsepower may only be considered a single basic model if:

(i) For ESCC, ESFM, IL, and RSV pumps, each motor offered in the basic model has a nominal full load motor efficiency rated at the Federal minimum (see the current table for NEMA Design B motors at § 431.25) or the same number of bands above the Federal minimum for each respective motor horsepower (see Table 3 of appendix A to subpart Y of this part); or

(ii) For ST pumps, each motor offered in the basic model has a full load motor efficiency at the default nominal full load submersible motor efficiency shown in Table 2 of appendix A to subpart Y of this part or the same number of bands above the default nominal full load submersible motor efficiency for each respective motor horsepower (see Table 3 of appendix A to subpart Y of this part).

10 CFR 431.462.

In the December 2021 NOPR, DOE stated that only the general provisions of the basic model definition would be applicable to circulator pumps and no additional provisions specific to circulator pumps would be necessary. 86 FR 72096, 72106. DOE requested comment on the proposed applicability of the definition of “basic model” at 10 CFR 431.462 to circulator pumps and any characteristics unique to circulator pumps that may necessitate modifications to that definition.

Id.

HI and Grundfos agreed that the main paragraph of the basic model definition is accurate for circulator pumps, but stated that DOE should explicitly exclude parts 1, 2, and 3 of the definition. (HI, No. 9 at p. 4; Grundfos, No. 7 at p. 2)

As discussed in the December 2021 NOPR, provisions (1)-(3) of the basic model definition would not apply to circulator pumps based on the nature of how circulator pumps are designed and distributed in commerce. 86 FR 72096, 72106. Therefore, DOE does not need to exclude these provisions explicitly and instead applies the existing definition of “basic model” at 10 CFR 431.462 to circulator pumps, consistent with the application of that definition to dedicated-purpose pool pumps, for which provisions (1)-(3) would also not be applicable due to lack of variation in stages and impeller trims within a pump model.

C. Rating Metric

In the December 2021 NOPR, DOE proposed to adopt the CEI metric as the performance-based metric for representing the energy performance of circulator pumps, as defined in equation (1), and consistent with Section 41.5.3.2 of HI 41.5-2021. 86 FR 72096, 72107. DOE noted that while HI 41.5-2021 defines the denominator as CER

REF

, DOE believed that the terminology CER

STD

is more reflective of the Federal energy conservation standards.

Id.

Any standards considered for any circulator pumps for which the CEI is applicable would use this metric as a basis for the standard level.

ER19SE22.017

Where:

CER = circulator energy rating (hp); and

CER

STD

= circulator energy rating for a minimally compliant circulator pump serving the same hydraulic load.

Id.

In the December 2021 NOPR, DOE stated that the CPWG specified a method for determining the denominator of the metric with procedures to determine the minimally compliant overall efficiency at the various test points based on the hydraulic performance of the rated circulator pump. 86 FR 72096, 72106; (Docket No. EERE-2016-BT-STD-0004, No. 98 Recommendations #1 and 2A-D at pp. 1-4). As discussed, the denominator would represent the energy efficiency of a circulator pump that is minimally compliant with the applicable energy conservation standard, should DOE establish such a standard. Were DOE to conduct a rulemaking to propose energy conservation standards for circulator pumps, DOE would discuss in detail the derivation of the denominator, as well as an analysis as required by EPCA to evaluate any such standard level to determine the level designed to achieve the maximum improvement in energy efficiency that is technologically feasible and economically justified, as required under EPCA.

DOE noted that the recommended method for determining the denominator relies on the hydraulic horsepower of the rated circulator pump, which was also discussed in the December 2021 NOPR. 86 FR 72096, 72106-72107.

For more information on any energy conservation standard rulemaking for circulator pumps, see Docket No. EERE-2016-BT-STD-0004.

DOE requested comment on its proposal to adopt CEI as the metric to characterize the energy use of certain circulator pumps and on the proposed equation for CEI.

Id.

at 86 FR 72107.

HI, Grundfos, NEEA, and NYSERDA supported adoption of CEI. (HI, No. 9 at p. 5; Grundfos, No. 7 at p. 2; NEEA, No. 11 at p. 2; NYSERDA, No. 6 at p. 2) NYSERDA noted that CEI is consistent with HI 41.5-2021, developed by CPWG members based on the approved CPWG term sheet, and supported by a variety of stakeholders. (NYSERDA, No. 6 at p. 2) DOE notes that HI 41.5-2022 has the same definition of CEI as HI 41.5-2021.

For the reasons discussed in the December 2021 NOPR and in the preceding paragraphs, in this final rule, DOE adopts CEI as the metric to characterize the energy use of circulator pumps and the equation for CEI as proposed in the December 2021 NOPR.

D. Test Methods for Different Circulator Pump Categories and Control Varieties

In the December 2021 NOPR, DOE stated that many circulator pumps are sold with a variable speed drive and controls (

i.e.,

logic or user interface) with various control strategies that reduce the required power input at a given flow rate to save energy. The primary varieties of control recommended by the CPWG include manual speed controls, pressure controls, temperature controls, and external input signal controls. (Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendations #4 at p. 4) For the test procedure to produce results that reflect variations in energy consumption associated with the various control strategies that could be implemented in a circulator pump, the CPWG recommended that DOE establish different test methods for each control variety in the circulator test procedure. 86 FR 72096, 72107; (Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendations #6A and #6B at pp. 4-6).

Section III.D.1 discusses DOE's definitions for each of these circulator pump control varieties.

Section III.D.2 discusses the reference system curve that serves as a basis for rating each variety of circulator pump controls.

Sections III.D.3 through III.D.7 discuss the specific test provisions for pressure controls, temperature controls, manual speed controls, external input signal controls, and no controls,

respectively.

In this document, circulator pumps with “no controls” are also inclusive of other potential control varieties that are not one of the specifically identified control varieties.

See

section III.D.7 of this document.

In response to the December 2021 NOPR, NEEA stated that they agreed with the proposed procedures for specific circulator types and control methods. (NEEA, No.11 at p. 2) Joint Advocates stated that they support the use of unique test point weights for different control types. (Joint Advocates, No. 8 at p. 1)

In the December 2021 NOPR, DOE considered incorporating HI 41.5-2021, “Hydraulic Institute Program Guideline for Circulator Pump Energy Rating Program,” which provides additional instructions for testing circulator pumps to determine an Energy Rating value for different circulator pump control varieties. DOE tentatively determined not to directly incorporate HI 41.5-2021. Unlike HI 40.6-2021, which is an industry test standard, HI 41.5-2021 is a guideline for participation in an industry program and includes many provisions not relevant to DOE. However, DOE preliminarily determined that its proposed test methods and calculations that supplement the proposed incorporation by reference of HI 40.6-2021, as discussed in sections III.D and III.E.2.c of this document, were consistent with HI 41.5-2021. 86 FR 72096, 72099.

In response to the December 2021 NOPR, HI requested that DOE incorporate by reference appropriate sections of HI 41.5-2021, instead of restating the requirements in the test procedure, noting support from additional stakeholders in response to the May 2021 RFI. (HI, No. 9 at p. 1) HI stated that this will reduce testing burden by eliminating confusion between DOE's test procedure and HI's standard and will significantly simplify and shorten the regulatory text language in appendix D. HI stated that many of DOE's requests for comment in the December 2021 NOPR were fully covered by HI 41.5, and slight changes by DOE could cause confusion in the market while not being beneficial to energy efficiency. (HI, No. 9 at pp. 1-2). HI did not recommend that DOE incorporate by reference HI 41.5 in full, but rather that DOE incorporate a table summarizing the appropriate Section of HI 41.5-2021 for each control method, and by referencing the appropriate Section of HI 41.5-2021 in each applicable section of the regulatory text. (HI, No. 9 at pp. 2-3).

Grundfos stated that DOE should incorporate HI 41.5-2021, Table 41.5.3 into appendix D, similar to Table 1 in appendix A, to clarify what testing is required based on the control method(s) of a circulator pump and to directly reference HI 41.5-2021 for testing

procedures instead of recreating the language within the test procedure itself. (Grundfos, No .7 at p. 7)

NEEA also disagreed that DOE is not able to adopt HI 41.5-2021 directly. NEEA stated that while HI 41.5-2021 is a rating guide for HI's Energy Rating program for circulators, it also contains the necessary test provisions for circulators and is identical to the test procedure DOE proposed. As such, NEEA found this proposal in the December 2021 NOPR to be confusing and burdensome for manufacturers and the market, as manufacturers have invested in testing and rating circulators according to HI 41.5-2021 and labeling equipment accordingly. NEEA noted that if there are minor difference between DOE's proposal and HI 41.5-2021, retesting might be required to ensure compliance without substantively affecting the efficiency of the equipment or the overall test result. NEEA stated that it would be more simple and less confusing to have just one test procedure for CEI. NEEA recommended that DOE reference the appropriate sections in HI 41.5-2021, rather than writing each section out in full. (NEEA, No. 11 at pp. 2-3) NEEA's suggestions for references are consistent with those provided by HI.

Following publication of the December 2021 NOPR, HI released a new version of HI 41.5, HI 41.5-2022 “Hydraulic Institute Program Guideline for Circulator Pump Energy Rating Program”. In this version of the industry guideline, HI corrected errors in certain test methods, provided additional specificity regarding certain provisions, and removed provisions specific to the HI Energy Rating program. These changes are discussed in the following subsections. Having considered comments suggesting that adding additional regulatory text would be confusing and burdensome, and due to the changes made in HI 41.5-2022, DOE is incorporating by reference HI 41.5-2022, adopting only sections specific to the test methods for control modes as requested by stakeholders. This limitation of the reference addresses DOE's concerns about the inclusion of provisions not relevant to DOE.

In the December 2021 NOPR, DOE proposed that manufacturers could select the control variety used for testing if the circulator pump model is distributed in commerce with multiple control varieties, which DOE expected would typically be the least consumptive control mode. However, DOE proposed that manufacturers may select multiple control varieties with which to test their circulator pumps and noted that DOE would address certification requirements in any future energy conservation standard rulemaking.

DOE requested comment on this proposal. 86 FR 72096, 72108.

For more information on any energy conservation standard rulemaking for circulator pumps, see Docket No. EERE-2016-BT-STD-0004.

Joint Advocates stated that when given the option to choose a control variety for rating, it is expected that most manufacturers would choose the least consumptive control curve, so in practicality there would be little difference between the “manufacturer-selected” and the “least-consumptive” control methods. Joint Advocates stated that requiring additional reporting of ratings representing the “most-consumptive” control method may encourage adoption of energy efficient options and would better inform purchases. (Joint Advocates, No. 8 at p. 3)

Joint Advocates and CA IOUs noted that the HI labeling program requires testing of the most and least consumptive control modes. (Joint Advocates, No. 8 at p. 3; CA IOUs, No. 10 at p. 1) CA IOUs added that manufacturers are intended to compete primarily on the least consumptive control mode, that most manufacturers are participating, and that therefore manufacturers will have test data in hand for both most and least consumptive control modes. (CA IOUs, No. 10 at pp. 1-2)

CA IOUs agreed with DOE's reasoning that the least consumptive control mode is where the products are most easily differentiated from each other and is representative of the circulator product performance in the field under a variety of scenarios. CA IOUs noted that there would be no need for DOE to specify least consumptive prescriptively and supported the proposal that manufacturers select the control mode to be tested. (CA IOUs, No. 10 at p. 2)

CA IOUs recommend that DOE require reporting of the most consumptive product performance values and reporting of the control type used for certification rating (

i.e.,

least consumptive). CA IOUs noted that the most consumptive control mode data is a direct indication of product mechanical performance at the CEI rating load points, unlike the least consumptive mode which also assesses the control system's performance. (

Id.

) CA IOUs also noted that the control scheme used can have a considerable influence on the results of the CEI rating at the least consumptive control method, so the CA IOUS recommended that control scheme used as part of rating should be reported in a supplemental information field. CA IOUs recommended that adaptive pressure controls have a unique control classification as part of the rating. (

Id.

)

NEEA recommended that DOE require testing in the most consumptive control strategy, likely full speed, and set the performance standard at efficiency level (“EL”) 1.5 (

i.e.,

a nominally lower efficiency level than the EL2 recommended by the CPWG). NEEA stated that the intent of a DOE standard and the CPWG recommendation is to raise the performance of all circulators in commerce to a minimum threshold, which should be one to be powered by electrically commutated (“EC”) motors. NEEA stated that the proposed test procedure requires circulators to be capable of reaching the required efficiency level but allows equipment to operate below the rated efficiency when installed. NEEA stated that this approach is not an appropriate regulatory mechanism nor is it representative of how circulators are operated in the market. Therefore, NEEA recommended testing in the most consumptive control strategy. (NEEA, No. 11 at p. 2) NEEA added that non-guaranteed performance would discourage utility circulator energy conservation programs. (NEEA, No. 11 at p. 7) NEEA stated that a DOE standard based on the most consumptive control setting creates a baseline above which utilities can incentivize increased performance, such as using the least consumptive control setting. (NEEA, No. 11 at p. 9)

NEEA stated that it believed the CPWG intent was for all circulator pumps sold in commerce to be equipped with either an EC motor or advanced controls. NEEA stated that by using least consumptive as the standard, installers would have the option to choose between controls that meet DOE's standard and controls that do not. NEEA stated that it did not believe that the least consumptive setting available is representative of how circulators with multiple control strategies will be installed, and that at this time information on what is representative is not available (NEEA, No. 11 at p. 6)

NEEA commented that not all EC motors meet EL 2 (the level recommended by the CPWG), and as such EL 1.5 might be appropriate when paired with a most consumptive requirement (which would tend to produce lower ratings for a given circulator pump model). NEEA stated that if DOE allows manufacturers to choose the control setting, then EL2 is appropriate. (NEEA, No. 11 at p. 7) NEEA stated that testing in the most consumptive setting and using EL 1.5 as

the standard allows DOE to increase the standard in future circulator rulemakings, which would be difficult based on least consumptive settings. (NEEA, No .11 at p. 9)

NEEA also recommended that DOE allow manufacturers to test in another control setting of their choosing to represent the range of efficiency available in a product to the market, and that the CEI of the most consumptive control strategy and any other CEI be reported to DOE and included on the circulator nameplate. (NEEA, No. 11 at p. 6) NEEA stated that multiple ratings would support the market in adopting energy efficient options and technologies beyond the minimum threshold set by the standard. NEEA noted that manufacturers already support testing in most consumptive control setting through the HI Energy Rating program. (NEEA, No. 11 at p. 8)

HI stated that, for DOE compliance, the manufacturer should be able to select any control mode that results in a compliant rating. (HI, No. 9 at p. 4) Grundfos agreed that the manufacturer should be allowed to select the control method tested. However, Grundfos stated that reporting of the control method used, and the actual parameters of the testing need to be addressed in detail in the circulator efficiency standard. Grundfos gave as an example, where a user can adjust setpoints for maximizing their system, this should be detailed in reporting to DOE, so repeatability of testing is possible. (Grundfos, No. 7 at p. 2)

DOE is adopting provisions in section 2.2 of appendix D to allow manufacturers to use the DOE test procedure to test any control variety available on a given circulator pump model, as proposed in the December 2021 NOPR. In response to NEEA's recommendation that DOE require testing in the most consumptive control strategy, DOE notes that circulator pumps may be sold with multiple control varieties, and DOE has determined that consumers may benefit from having access to CEI ratings at full speed and with various control options. Whether compliance with any standard established, should energy conservation standards be established, would be based on a specific control mode (or no controls), or whether certain information related to the control mode used for testing would be required as part of certification, would be addressed in an energy conservation standard rulemaking.

1. Definitions Related to Circulator Pump Control Varieties

In the December 2021 NOPR, DOE proposed to define external input signal control, manual speed control, pressure control, and temperature control as recommended by the CPWG and consistent with HI 41.5-2021:

•

Manual speed control

means a control (variable speed drive and user interface) that adjusts the speed of a driver based on manual user input.

•

Pressure control

means a control (variable speed drive and integrated logic) that automatically adjusts the speed of the driver in response to pressure.

•

Temperature control

means a control (variable speed drive and integrated logic) that automatically adjusts the speed of the driver continuously over the driver operating speed range in response to temperature.

•

External input signal control

means a variable speed drive that adjusts the speed of the driver in response to an input signal from an external logic and/or user interface.

86 FR 72096, 72108-72109.

DOE also proposed to define adaptive pressure control as follows:

Adaptive pressure control

means a pressure control that continuously senses the head requirements in the system in which it is installed and adjusts the control curve of the pump accordingly.

DOE requested comment on this definition. 86 FR 72096, 72109.

In response, HI suggested modifications to the proposed definition and stated that adaptive pressure control pumps do not always operate continuously. HI proposed the following definition:

Adaptive pressure control

means a pressure control that senses the head requirements in the system in which it is installed and adjusts the pump control curve accordingly.

(HI, No. 9 at p. 4)

Grundfos agreed with the suggested modification detailed by HI. (Grundfos, No. 7 at p. 2)

In this final rule, for the reasons discussed in the December 2021 NOPR, DOE adopts the definitions for external input signal control, manual speed control, pressure control, and temperature control as proposed in the December 2021 NOPR. For the reasons discussed in the NOPR, and in order to capture controls that do not always operate continuously, as identified by HI and Grundfos, DOE is adopting the definition for adaptive pressure control as recommended by HI and Grundfos.

2. Reference System Curve

In the December 2021 NOPR, DOE stated that all recommended test methods for circulator pump control varieties, which involve variable speed control of the circulator pump, specify test points with respect to a representative system curve. 86 FR 72096, 72109. That is, for circulator pumps with manual speed controls, pressure controls, temperature controls, or external input signal controls, a reference system curve is implemented to be representative of the speed reduction that is possible in a typical system to provide representative results.

Id.

For circulator pumps with no controls, no reference system is required as measurements are taken at various test points along a pump curve at maximum speed only.

Id.

Such a reference system curve describes the relationship between the head and the flow at each test point in a typical system. Additionally, a reference system curve that is representative of a typical system in which circulator pumps are installed may also allow for the differentiation of control varieties to be reflected in the resulting ratings. DOE proposed to incorporate a quadratic reference system curve as recommended by the CPWG and consistent with HI 41.5-2021, which includes this reference curve in each of the individual control test methods (sections 41.5.3.4.2 #3d, 41.5.3.4.3 #2, 41.5.3.4.4.1 #2, 41.5.3.4.4.2 #2, and 41.5.3.4.5 #2d).

Id.

The proposed reference system curve intersects the BEP and has a static offset of 20 percent of BEP head, as shown in equation (2).

ER19SE22.018

Where:

H = the pump total head (ft),

Q = the flow rate (gpm),

100

= flow rate at 100 percent of BEP flow (gpm), and

100

= pump total head at 100 percent of BEP flow (ft).

86 FR 72096, 72109-72110.

DOE received no comments on the proposed reference system curve. As noted in section II, DOE is incorporating by reference sections of HI 41.5-2022 for each control mode test method, which include the reference curve equation, and is the same as HI-41.5-2021. As such, DOE is adopting the proposed reference curve through reference to HI 41.5-2022 and is not establishing an additional section in its test procedure specifying the reference curve as applicable to all test methods.

As such, DOE adopts the curve as described in Equation 2 and proposed in the December 2021 NOPR. Pressure Control.

In the December 2021 NOPR, DOE proposed a test method for circulator pumps with pressure controls consistent with the method included in HI 41.5-2021 and deviating from that proposed by the CPWG. 86 FR 72096, 72111-72112. Specifically, DOE proposed that circulator pumps with pressure controls be tested at test points of 25, 50, 75, and 100 percent of BEP flow based on a manufacturer-selected control curve that is available to the end user, must produce a head equal to or greater than 25 percent of BEP head at a minimum of one test point, and must achieve 100 percent BEP flow of the reference curve.

Id.

at 86 FR 72112. DOE proposed that such the test points may be obtained based on automatic speed adjustment, manual speed adjustment, or simulated pressure signal, or a combination of these adjustments, including throttling.

Id.

Additionally, DOE proposed that the CEI for circulator pumps with pressure controls be calculated with the unique weights and test points as shown in equation (3):

ER19SE22.019

Where:

CER = circulator pump energy rating (hp);

= weight of 0.05, 0.40, 0.40, and 0.15 at test points of 25, 50, 75, and 100 percent of BEP flow, respectively;

in,i

= power input to the driver at each test point i (hp); and

i = test point(s), defined as 25, 50, 75, and 100 percent of the flow at BEP.

Id.

at 86 FR 72110.

Additionally, in a deviation from CPWG recommendations and based on stakeholder comments on the May 2021 RFI and the contents of HI 41.5-2021, DOE stated that it agreed with commenters that it is important for the test method to capture the variety of pressure controls on the market, and that correction back to the reference curve would prevent any unfair advantage among the variety of controls on the market.

Id.

at 86 FR 72112. DOE requested comment on the proposed test method for circulator pumps with pressure controls.

Id.

Joint Advocates supported the proposed update, consistent with HI 41.5-2021, relating to pressure control system test points, stating that they understand that many programmed control curves were not testable under the older methodology because the control systems of some circulator pumps may operate at head pressures below the reference curve provided in HI 41.5-2018. Referring to the proposed update and the contents of HI 41.5-2021, Joint Advocates added that they understand that the power correction back to the reference curve assumes a constant pump efficiency, is valid, and does not give an arbitrary advantage to products using this assumption. (Joint Advocates, No. 8 at p. 2) Grundfos stated that DOE should not recreate language from HI 41.5 and instead point to HI 41.5.3.4.2 for testing circulator pumps with pressure controls. (Grundfos, No. 7 at p. 2)

In the December 2021 NOPR, DOE stated that it was aware of some circulator pumps that are equipped with user-adjustable pressure controls such that the maximum and minimum head values on the control curve can be set to specifically match the system into which the pump is being installed. 86 FR 72096, 72112. DOE's interpretation of HI 41.5-2021 was that these types of controls are not addressed in the industry standard. To test such controls, DOE proposed that the maximum and minimum head values on user-adjustable pressure controls may be adjusted, if possible, to coincide with a maximum head value at the pump's BEP and a minimum head value equivalent to 20 percent of the BEP head value (consistent with the static offset of the proposed reference system curve).

Id.

If only the maximum or minimum head value can be adjusted, DOE proposed that only the adjustable setting would be adjusted. In either case, DOE also proposed that the settings can be adjusted for testing only if they are adjustable by the user.

Id.

DOE stated that this proposed methodology would result in the most representative performance of such adjustable controls by preventing the testing of specifically tuned control options that would not be representative of likely field performance.

Id.

DOE noted that further adjustment to attain 100 percent of BEP head would be required.

Id.

In summary, for adjustable pressure controls with user-adjustable maximum and/or minimum head values, DOE proposed to allow one-time manual adjustment of the maximum and/or minimum control curve head values, as applicable, to coincide with a maximum head value at the pump's BEP and a minimum head value equivalent to 20 percent of the BEP head value with all subsequent test points taken along the adjusted control curve. DOE requested comment on whether specific test provisions for circulator pumps equipped with user-adjustable pressure controls are needed, and if so, on the proposed provisions for such pumps.

Id.

Joint Advocates supported DOE's approach to testing user-adjustable controls, noting that DOE's interpretation of HI 41.5-2021 is that these controls are not addressed in the industry standard. Joint Advocates stated that, importantly, DOE's proposal states that settings can only be adjusted for testing if they are adjustable by the user, which would prevent testing of specifically tuned control options that are not representative. (Joint Advocates, No. 8 at pp. 2-3)

HI and Grundfos stated that circulator pumps with user-adjustable pressure controls are addressed in HI 41.5-2021 in section 41.5.3.4.2 and should be tested accordingly. (HI, No. 9 at pp. 4-5; Grundfos, No. 7 at p. 2) HI noted that no special provisions or alternative test

methods are needed. (HI, No. 9 at p. 5) Grundfos added that DOE should properly collect this adjustment data through reporting for repeatable testing. (Grundfos, No. 7 at p. 2)

Upon review of HI 41.5-2021, DOE finds that its proposals in the December 2021 NOPR related to adjustable pressure controls are a more specific implementation of the requirements for pressure controls in section 41.5.3.4.2 #3. Specifically, user-adjustable controls allow the user to create a control curve, and the control curve created by adjusting the maximum and/or minimum head values must be available to the end user, produce a head equal to or greater than 25 percent of BEP head at a minimum of one test point, and achieve 100 percent BEP flow of the reference curve. While DOE's proposal has more specificity that could increase repeatability, DOE notes that all of DOE's proposed test methods for the various speed control varieties, as well as the methods in HI 41.5-2022, allow some discretion by the manufacturer with regard to exactly which settings to use. As such, DOE is not adopting its proposal specific to user-adjustable controls, and, in response to Grundfos, DOE will address certification reporting requirements related to control curve settings in a separate rulemaking.

In the December 2021 NOPR, DOE stated that adaptive pressure controls are installed in similar applications as pressure controls but can also be effective at reducing the head and flow provided in single-zone systems to adjust for typical pump oversizing. Also, due to the ability of adaptive pressure controls to measure and automatically adjust to the system requirements over time, adaptive pressure controls can result in optimized performance and energy use as compared to pressure-based controls. 86 FR 72096, 72112.

Consistent with HI 41.5-2021, for adaptive pressure controls, DOE proposed to test at each test point at the minimum thresholds for head noted in the manufacturer literature or the head values specified along the reference system curve, whichever is greater. In addition, although not included in HI 41.5-2021, DOE also proposed that if the pump does not have a manual control mode available, the speed would be adjusted based on the pressure control mode with the lowest head at each load point, and if the selected pressure control results in a head value below the reference system curve, the pump would be throttled to achieve a head value at or above the reference system curve. 86 FR 72096, 72114.

DOE requested comment on the proposed test methods for circulator pumps with adaptive pressure controls, and, in particular, on the proposed provisions not included in HI 41.5-2021, including for pumps without a manual control mode, whether throttling should be allowed to achieve head above the reference system curve, or instead head should be allowed below the reference system curve and adjusted back to the curve, as with other non-adaptive pressure controls. DOE also requested comment on the HI 41.5-2021 provision for manual adjustment to achieve 100 percent BEP flow and head point at max speed, which is not included for other pressure controls.

Id.

Joint Advocates supported the proposed test methodology for adaptive pressure controls as a reasonable approach, while encouraging DOE in the future to gather field data related to real-world operating points. (Joint Advocates, No. 8 at p. 2)

HI and Grundfos stated that HI 41.5-2021 treats adaptive pressure controls with the same methodology as all pressure controls, and that section 41.5.3.4.2 #4 is a subset of the pressure testing methodology and not a standalone test methodology. (HI, No. 9 at p. 5; Grundfos, No. 7 at p. 2) HI added that it would be rare that the circulator BEP would be outside of the adaptive controls operating area, so the difference between throttling and adjusting back to the curve would not be an issue, unless the BEP is outside the control area. HI stated that a pump without manual speed adjustment would still allow use of a throttling equivalent (as noted in section 41.5.3.4.2 #2b) to get back to the BEP flow, which can then be corrected back to BEP on the reference curve. (HI, No. 9 at p. 5)

In response to HI and Grundfos, DOE notes that HI 41.5-2021 contained discrepancies with regard to the methodology in section 41.5.3.4.2 #4 (adaptive pressure controls) compared to #2 and #3 (all pressure controls). Specifically, #4 only allows manual speed adjustment, while #2 also allows throttling and simulated pressure signal. In addition, #4 requires head values to be above the reference curve, while #3 does not require this. In the recent publication of HI 41.5-2022, HI included several updated to section 41.5.3.4.2 that address DOE's proposals related to adaptive pressure controls, specifically removing the identified discrepancies, so that #4 now provides additional testing provisions for adaptive pressure controls, but not conflicting provisions. This update indicates that the provision requiring adaptive pressure controls to achieve head values at or above the reference curve was erroneous.

In addition, HI 41.5-2022 has moved the contents of section 41.5.3.4.2 #5, which discussed the choice and reporting of factory control curves specific to the HI Energy Rating Program, but not necessary for conduct of the test method, to a separate section of the guideline. As such, DOE will reference the entire section.

For these reasons, DOE is adopting the test method for pressure speed controls by referencing HI 41.5-2022 section 41.5.3.4.2. As noted, this test method contains some differences from the test method proposed by DOE in that it does not include specific provisions for user-adjustable controls, which DOE has determined are not necessary, and that it has revised the test method for adaptive pressure controls to be more consistent with the test method for pressure controls in general, while providing necessary additional specifications. The overall test method for pressure controls in HI 41.5-2022 section 41.5.3.4.2 in general is consistent with that proposed in the December 2021 NOPR. DOE has determined that the revised test method for adaptive pressure controls will produce representative results for such equipment and would not be unduly burdensome to conduct.

3. Temperature Control

Temperature controls are controls that automatically adjust the speed of the variable speed drive in the pump continuously over the operating speed range to respond to a change in temperature of the operating fluid in the system. Typically, temperature controls are designed to achieve a fixed temperature differential between the supply and return lines and adjust the flow rate through the system by adjusting the speed to achieve the specified temperature differential. Similar to pressure controls, temperature controls are also designed primarily for hydronic heating applications. However, temperature controls may be installed in single- or multi-zone systems and will optimize the circulator pump's operating speed to provide the necessary flow rate based on the heat load in each zone. Unlike pressure controls, there are no minimum head requirements inherent to the temperature control, so temperature controls have the potential to use the least amount energy to serve a given load. 86 FR 72096, 72114.

The CPWG recommended that for circulator pumps distributed in commerce with temperature controls, PER

CIRC

should be calculated in the

same way and with the same weights as for pressure controls, as shown in equation (4). (Docket No. EERE-2016- BT-STD-0004, No. 58 Recommendation #6A at pp. 4-5)

In the December 2021 NOPR, DOE tentatively determined that the CPWG recommendation for temperature controls would allow for temperature controls to be tested in a way that captures the potential energy savings from this control variety without being overly burdensome for manufacturers to conduct. Therefore, DOE proposed to adopt the recommendations of the CPWG to test temperature controls based on manual speed adjustment or with simulated temperature signal to activate the temperature-based control to achieve the test point flow rates with a head at or above the reference system curve. Additionally, DOE proposed to use the weights and test points shown in equation (4) of the December 2021 NOPR (equation (3) in this final rule) for circulator pumps distributed in commerce with temperature controls. DOE requested comment on the proposed test methods, test points, and weights for circulator pumps with temperature controls. 86 FR 72096, 72115.

Joint Advocates supported testing of temperature controls as recommended by the CPWG. (Joint Advocates, No. 8 at p. 1) HI agreed with the proposed testing of temperature controls but noted that the terminology in the equations should be updated to reflect CEI and CER. (HI, No. 9 at p. 6) Grundfos agreed with the temperature control testing but stated that DOE should directly reference HI 41.5.3.4.3 instead of recreating this language within the test procedure. (Grundfos, No. 7 at p. 3)

In response to HI, DOE notes that the regulatory text proposed in section V.C of appendix D reflected CER terminology. 86 FR 72096, 72144. This proposed regulatory text, which DOE based on the test procedure from HI 41.5-2021, is consistent with the content of HI 41.5-2022. DOE adopts the test method for temperature controls as proposed, but instead of including regulatory text, DOE is referencing HI 41.5-2022 section 41.5.3.4.3, as requested by stakeholders. This section is consistent with the regulatory text proposed in the NOPR, and as such does not representative a substantive change.

4. Manual Speed Control

In the December 2021 NOPR, DOE proposed to test circulator pumps with manual speed controls consistent with the provisions in Section 41.5.3.4.5 of HI 41.5-2021, as follows: (1) the tested control must produce head equal to or greater than 25 percent of BEP head at a minimum of one test point (HI 41.5-2021 section 41.5.3.4.5 #2a), and (2) the control curve setting being evaluated must achieve 100 percent BEP flow of the reference curve (HI 41.5-2021 section 41.5.3.4.5 #2b). DOE also proposed that the CER be calculated as the weighted average of P

in,max

and P

in,reduced

, as shown in equations (5), (6), and (7):

ER19SE22.020

Where:

CER = circulator pump energy rating (hp);

max

= speed factor weight of 0.75;

in_max

= weighted average input power at maximum rotating speed of the circulator (hp), as specified in equation (6);

reduced

= speed factor weight of 0.25; and

in_reduced

= weighted average input power at reduced rotating speed of the circulator (hp), as specified in equation (7).

ER19SE22.021

Where:

in_max

= weighted average input power at maximum speed of the circulator (hp);

i_max

= 0.25;

in,i_max

= power input to the driver at maximum rotating speed of the circulator pump at each test point i (hp); and

i = test point(s), defined as 25, 50, 75, and 100 percent of the flow at BEP.

ER19SE22.022

Where:

in_reduced

= weighted average input power at reduced speeds of the circulator (hp);

i_reduced

= 0.3333;

in,i_reduced

= power input to the driver at reduced rotating speed of the circulator pump at each test point i (hp); and

i = test point(s), defined as 25, 50, and 75 percent of the flow at BEP of max speed.

86 FR 72096, 72115-72116.

Additionally, in a deviation from CPWG recommendations and based on stakeholder comments on the May 2021 RFI and the contents of HI 41.5-2021, DOE did not propose that all test points

on a control curve must exist above the reference curve. DOE noted that HI 41.5-2021 section 41.5.3.4.5 #3 still retained that provision, which DOE assumed to be an error based on HI's comments and recommendations in response to the May 2021 RFI. 86 FR 72096, 72116.

DOE tentatively determined that the proposed test methods for manual speed control circulator pumps are appropriate and representative, as they account for the likelihood that a circulator pump with manual speed controls will be installed and operated at maximum speed, but also accounts for the potential energy savings associated with reduced speed operation. 86 FR 72096, 72116. DOE requested comment on the proposed test method and the unique test points, weights, and speed factors for circulator pumps distributed in commerce with manual speed controls.

Id.

at 86 FR 72117.

Grundfos continued to state, as it did in response to the May 2021 RFI, that manual speed control should not be a separate test method, as the devices are typically operated 75 percent of the time at full speed, and a manufacturer could benefit by adding alternate speeds that are never used. Grundfos suggested that if manual speed testing is maintained, a CEI value should be required for each setting available to consumers so that consumers can understand the true efficiency. (Grundfos, No. 7 at p. 3)

As discussed in the December 2021 NOPR, the CPWG addressed the issues raised by Grundfos in discussing how the test points at maximum speed were designed to represent the performance at maximum speed and account for operation at maximum speed the majority of the time, while the test points at reduced speed allowed some “credit” for being able to reduce speed. 86 FR 72096, 72116; (Docket No. EERE-2016-BT-STD-0004, No. 70 at p. 201-202) The CPWG concluded that about 75 percent of the time, circulator pumps with manual speed controls are operated at maximum speed, as reflected in its recommended procedure. (Docket No. EERE-2016-BT-STD-0004, No. 71 at p. 377) For these reasons, DOE proposed to include manual speed control as a test method in the circulator pump test procedure. 86 FR 72096, 72116. Grundfos did not add additional information in their comment in response to the December 2021 NOPR, and as such DOE is adopting a test method for circulator pumps with manual speed control in this final rule. DOE will address Grundfos' suggestion for CEI ratings for multiple settings in a separate certification rulemaking.

Joint Advocates supported testing manual controls with test point weightings as recommended by the CPWG and using updated testing methodology consistent with HI 41.5-2021, for the same reasons discussed for pressure controls. (Joint Advocates, No. 8 at p. 1-2) HI supported the proposed testing for manual controls but noted that the terminology in the equations should be updated to reflect CEI and CER. (HI, No. 9 at p. 6) Grundfos stated that DOE should directly reference HI 41.5.3.4.5, instead of recreating this language within the test procedure. (Grundfos, No. 7 at p. 3)

In the December 2021 NOPR, DOE noted that HI 41.5-2021 section 41.5.3.4.5 #3 includes a provision for head to be at or above the reference curve, as originally recommended by the CPWG, which DOE assumed to be an error based on HI's comments and recommendations in response to the May 2020 RFI. DOE also noted that the introductory text of HI 41.5-2021 section 41.5.3.4.5 specifies that the test method applies to manual speed control, which can be operated without an external input signal, but DOE stated it believed this provision is superfluous as manual speed controls by definition do not require an external input signal. 86 FR 72096, 72116-72117. DOE did not include these provisions in its proposed test method for manual speed control. DOE did not receive comments specifically related to these issues, but in the recent publication of HI 41.5-2022, the provisions that DOE assumed to be erroneous have been removed. In response to HI's comments, the proposed regulatory text regarding the manual speed control test method did reflect CEI and CER; HI 41.5-2022 also reflects this terminology.

DOE also notes that in the proposed regulatory text for manual speed controls, DOE proposed that the control curve must be available to the end user. 86 FR 72096, 72142. This provision was not specified in HI 41.5-2021 but has been added to HI 41.5-2022. DOE has determined that this requirement will improve the representativeness of CEI ratings for circulator pumps with manual speed controls as it will prevent manufacturers from rating with speeds that cannot be used in the field. The remainder of the provisions in HI 41.5-2022 section 41.5.3.4.5 are consistent with DOE's proposals and with HI 41.5-2021.

For these reasons, DOE adopts the test method for manual speed control as proposed in the NOPR but is referencing HI 41.5-2022 section 41.5.3.4.5 instead of including regulatory text. This section is consistent with the regulatory text proposed in the NOPR, and as such does not representative a substantive change.

5. External Input Signal Control

In the December 2021 NOPR, DOE proposed to specify a test method for circulator pumps sold only with external input signal control and that cannot operate without an external input signal. 86 FR 72096, 72118. Specifically, DOE proposed to test along the reference system curve to achieve the test point flow rates with a head at or above the reference curve, and that CEI would be calculated as shown in equation (2) of the December 2021 NOPR (equation (1) in this final rule).

Id.

DOE also proposed that the speed of the pump could be adjusted using either manual speed adjustment or with a simulated external signal to achieve the specified flow rates.

Id.

at 86 FR 72141.

DOE also proposed to test circulator pumps sold with external input signal controls along with other controls, or which can be operated without an external input signal control, both: (1) along the maximum speed circulator pump curve to achieve the test point flow rates for the max speed input power values and (2) with speed adjustment that will achieve a head at or above the reference system curve at the test point flow rates for the reduced speed input power values. DOE proposed that in either case, either manual speed adjustment or simulated external input signal can be used to achieve the relevant flow rates. DOE did not propose that the speed adjustment include the “lowest speed setting” that results in a head value at or above the reference system curve, as recommended by the CPWG; however, DOE addressed this issue in its enforcement provision proposals. Finally, DOE proposed that the CEI should be calculated as the weighted average of P

in,max

and P

in,reduced

, as shown in equations (8), (9), and (10).

ER19SE22.023

Where:

CER = circulator pump energy rating (hp);

max

= speed factor weight of 0.30;

in_max

= weighted average input power at maximum rotating speed of the circulator pump (hp);

reduced

= speed factor weight of 0.70; and

in_reduced

= weighted average input power at reduced rotating speed of the circulator (hp).

ER19SE22.024

Where:

in_max

= weighted average input power at maximum speed of the circulator (hp);

i_max

= 0.25;

in,i_max

= power input to the driver at maximum rotating speed of the circulator pump at each test point i (hp); and

i = test point(s), defined as 25, 50, 75, and 100 percent of the flow at BEP.

ER19SE22.025

Where:

in_reduced

= weighted average input power at reduced speeds of the circulator pump (hp);

i_reduced

= 0.3333;

in,i_reduced

= power input to the driver at reduced rotating speed of the circulator pump at each test point i (hp); and

i = test point(s), defined as 25, 50, and 75 percent of the flow at BEP of max speed and head values at or above the reference curve.

86 FR 72096, 72117-72118.

DOE requested comment on the proposed test method and the unique test points, weights, and speed factors for circulator pumps distributed in commerce with external input signal controls. 86 FR 72096, 72118. In particular, DOE requested comment on whether manual speed adjustment and/or simulated external input signal are appropriate for testing circulator pumps with external input signal only, as well as circulator pumps with external input signal in addition to other control varieties.

Id.

DOE also sought comment on whether it is necessary to reference the “lowest speed setting” when determining the appropriate test points.

Id.

Finally, DOE sought comment on whether the test points and weights for circulator pumps distributed in commerce with external input signal control in addition to other control varieties are appropriately reflective of their energy consumption in the field relative to other control varieties.

Id.

In response, Grundfos stated that delta T and temperature control test methods should be combined.

Grundfos noted that the speed of the pump is the primary function determining efficiency, that both test methods control the pumps speed, as in both cases they simulate inputs to conduct testing and attempt to model the reference curve with those inputs, and therefore separate test requirements are not necessary. (Grundfos, No. 7 at p. 3).

Delta T and temperature controls refer to the same type of control. As discussed in the next paragraph, DOE believes this is an error.

DOE assumes that Grundfos is recommending that the test methods for temperature controls and external input signal controls be combined, as they suggested in response to the May 2021 RFI. (Grundfos, No. 113 at p. 4) As discussed in the December 2021 NOPR, the CPWG considered the category of external input signal controls as separate from temperature controls. Specifically, the CPWG noted that unlike pressure and temperature controls, for external input signal controls, the logic that defines how the circulator pump operating speed is selected in response to some measured variable (

e.g.,

temperature, pressure, or boiler fire rate) is not integral to the circulator as distributed in commerce. Instead, it is part of another control system, such as a building management system or a boiler control system. (Docket No. EERE-2016-BT-STD-0004, No. 72 at p. 83-84); 86 FR 72096, 72115.

DOE also noted that the test method recommended by the CPWG and in HI 41.5-2021 for circulator pumps with external input signal controls only and that cannot operate without an external signal control is the same as the test method for circulator pumps with temperature control. 86 FR 72096, 72115. However, the CPWG recommended, and HI 41.5-2021 included, a different test method for external input signal controls with other control varieties or that can be operated without external input signal control.

Id.

The CPWG asserted that if external input signal control is one of multiple options available on a circulator pump, or the pump is able to operate without an external input signal, it is less likely that the external input signal control option is going to be utilized since it requires external logic and equipment in order to operate properly. (Docket No. EERE-2016-BT-STD-0004, No. 72 at pp. 216-218, 229); 86 FR 72096, 72117. The CPWG recommended testing

circulator pumps with external input signal controls similar to manual speed controls. (Docket No. EERE-2016-BT-STD-0004, No. 47 at p. 480); 86 FR 72096, 72117.

For these reasons, DOE proposed separate test methods for temperature controls, external input signal controls only (identical to the test method for temperature controls), and external input signal controls with other control varieties. 86 FR 72096, 72115.

In its response to the December 2021 NOPR, Grundfos has not introduced additional information beyond that provided in its May 2021 RFI comments that would contribute to DOE amending the test methods as proposed. (See Grundfos, No. 7 at p. 3)

HI agreed with the proposal in the NOPR, which they stated is incorporated within the appropriate testing sections of HI 41.5-2021. (HI, No. 9 at p. 6) Grundfos stated that DOE should directly reference HI 41.5-2021 sections 41.5.3.4.4.1 for external control only and 41.5.3.4.4.2 for external control with other control methods, instead of recreating the language within the test procedure. (Grundfos, No. 7 at p. 3)

HI stated that additional clarification for “lowest speed setting” is not necessary. (HI, No. 9 at p. 6) Grundfos also stated that adding “lowest speed setting” to the testing requirements is not required for repeatability and would put test points at or near the minus 5 percent region of flow. Grundfos stated that DOE testing should attempt to achieve a head/flow as close to the reference curve/test point as possible. (Grundfos, No. 7 at p. 3)

In the December 2021 NOPR, DOE noted that HI 41.5-2021 contained some discrepancies between the two external input signal control methods regarding testing with manual speed adjustment and/or simulated external input signal. 86 FR 72096, 72118. DOE proposed to allow both manual speed adjustment and simulated external input signal for both test methods.

at 86 FR 72141.

No commenters responded to DOE's request regarding whether manual speed adjustment and/or simulated external input signal are appropriate for testing circulator pumps with external input signal only, as well as circulator pumps with external input signal in addition to other control varieties. However, in the recent publication of HI 41.5-2022, HI amended the test method to both allow manual speed adjustment and simulated external input signal, regardless of whether external input signal control is the only control mode, as proposed by DOE. The remainder of the provisions regarding external input signal controls are the same in HI 41.5-2022 as in HI 41.5-2021, and also consistent with DOE's proposals.

In response to the comments from HI and Grundfos, DOE is not adopting a reference to the “lowest speed” setting in the test method for external input control, consistent with the December 2021 NOPR proposal and HI 41.5-2022. DOE addresses enforcement testing in section III.F.2 of this document.

In this final rule, DOE is adopting the test methods for external input signal controls by referencing HI 41.5-2022 sections 41.5.3.4.4.1 and 41.5.3.4.4.2, rather than including regulatory text. The test methods in those sections of HI 41.5-2022 are consistent with that proposed by DOE and as such this does not represent a substantive change.

6. No Controls or Full Speed Test

In the December 2021 NOPR, consistent with the recommendations of the CPWG, DOE proposed to test circulator pumps without external input signal, manual, pressure, or temperature controls along the maximum speed circulator pump curve to achieve the test point flow rates. DOE agreed that since these circulator pumps with no controls are single-speed controls and only have a single speed, testing at maximum speed is representative of the typical operation of circulator pumps with no controls. Additionally, DOE proposed to use equation (11):

ER19SE22.026

Where:

CER = circulator pump energy rating (hp);

= 0.25;

in,i

= power input to the driver at each test point i (hp); and

i = test point(s), defined as 25, 50, 75, and 100 percent of the flow at BEP.

86 FR 72096, 72119.

To provide regulatory clarity about which pumps must be rated using the “no controls” test method, but also accommodate the option for any pump to be rated using the “no controls” test method, DOE proposed to refer to this test method in the regulatory text as the test method for circulator pumps without external signal, manual, pressure, or temperature controls (

i.e.,

full speed test). DOE also proposed additional language in the scope section regarding this clarification.

Id.

DOE requested comment on the proposed test method for circulator pumps distributed in commerce with no controls.

Id.

HI agreed with the proposal for pumps with no controls and stated that DOE should incorporate by reference section 41.5.3.4.1 for “Full speed or without pressure, temperature, external input signal or manual speed control.” (HI, No. 9 at p. 6) Grundfos also agreed with the proposed test method and stated that DOE should reference HI 41.5-2021 section 41.5.3.4.1, use language consistent with HI 41.5, and name this test method “Full speed.” (Grundfos, No. 7 at p. 3)

For the reasons discussed in the December 2021 NOPR and in the preceding paragraphs, DOE is adopting the proposed test method for circulator pumps without external input signal, manual, pressure, or temperature controls (full speed test) in this final rule. In response to HI and Grundfos, DOE is re-ordering the title of this test method to: “Testing and Calculation of CER for Full Speed Test and for Circulator Pumps without External Input Signal, Manual, Pressure, or Temperature Controls.” In addition, instead of including regulatory text, DOE is referencing HI 41.5-2022 section 41.5.3.4.1, which is identical to HI 41.5-2021 section 41.5.3.4.1, as requested by stakeholders. This section contains the same content as the NOPR proposal and does not represent a substantive change.

E. Determination of Circulator Pump Performance

In the December 2021 NOPR, DOE stated that as part of the September 2016 CPWG Recommendations, the CPWG recommended that all test points be tested on a wire-to-water basis, in accordance with HI 40.6-2014, with minor modifications. The CPWG also

recommended that if an updated version of HI 40.6 is published prior to publication of the test procedure final rule, DOE should review and incorporate the updated version. (Docket No. EERE-2016-BT-STD-0004, No. 58, Recommendation #10 at p. 8-9); 86 FR 24516, 24526. The CPWG also recommended several modifications related to frequency of data collection, BEP speed, electrical measurement equipment, relevant parameters at specific load points, power supply characteristics, and rounding of values for calculating and reporting purposes. (Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendation #10 at pp. 8-9). 86 FR 72096, 72119.

DOE noted that two updated versions of HI 40.6—HI 40.6-2016 and HI 40.6-2021—had been published since the CPWG meetings concluded. DOE proposed to incorporate by reference HI 40.6-2021, for measuring the performance of circulator pumps, noting the changes made from the previous version of HI 40.6-2014. DOE also stated that it was necessary to make several exceptions, modifications, and additions to this test procedure to ensure accuracy and repeatability of test measurements and that the test method produces results that reflect energy efficiency or energy use during a representative average use cycle without being unduly burdensome to conduct Additionally, DOE proposed specific procedures for calculating the CEI and rounding of values to ensure that the resultant ratings are determined in a consistent manner. 86 FR 72096, 72119. DOE discusses these proposals and their resulting requirements in the following subsections.

Section III.E.1 discusses HI 40.6-2021, the industry standard, which DOE is incorporating by reference, for measuring the performance of circulator pumps. DOE has determined that it is necessary to make several exceptions, modifications, and additions to this test procedure to ensure accuracy and repeatability of test measurements (sections III.E.2.a through III.E.2.c of this document) and that the test method produces results that reflect energy efficiency or energy use during a representative average use cycle without being unduly burdensome to conduct. Additionally, DOE adopts specific procedures for calculating the CEI and rounding of values to ensure that the resultant ratings are determined in a consistent manner (section III.E.2.d of this document).

1. Incorporation by Reference of HI 40.6-2021

In the December 2021 NOPR, DOE stated that it had reviewed HI 40.6-2021 and determined that the test methods contained within HI 40.6-2021 are generally consistent with HI 40.6-2014 and are sufficiently specific and reasonably designed to produce test results to determine a CEI that is representative of an average use cycle of applicable circulator pumps. Specifically, Table 40.6.2 of HI 40.6-2021, like HI 40.6-2014, defines and explains how to calculate driver power input,

volume per unit time,

pump total head,

and other relevant quantities, which are essential to determining the metric. 86 FR 72096, 72120.

The term “driver or control power input” in HI 40.6-2021 is defined as “the power input to the driver or control;” in the NOPR, DOE refers to “driver power input” as the power to either the motor or the controls, if present.

The term “volume per unit time” in HI 40.6-2021 is defined as “. . . the volume rate of flow in any given section . . . Also referred to as

flow, flow rate,

and

rate of flow.

”

The term “pump total head” is defined in HI 40.6-2021 as “the algebraic difference between the outlet total head and the inlet total head” and is used synonymously with the term “head” in this document.

HI 40.6-2021 also contains appropriate specifications regarding the scope of pumps covered by the test method, standard rating conditions, equipment specifications, uncertainty calculations, and tolerances. The electrical measurement specification and associated equipment specifications in Section C.4.3 of HI 40.6-2021 contain the relevant measurement specifications for certain non-energy metrics (

i.e.,

true root mean square “RMS” current, true RMS voltage, and real power) that manufacturers may choose to make representations about for each rated circulator pump. These specifications also describe the relevant measurements used in the calculation of true power factor (“PF”) at each applicable load point for each circulator pump control variety, a non-energy metric manufacturers may wish to use to make representations. In addition, HI 40.6-2021 contains a new appendix E with specific test instructions for circulator pumps. DOE noted that Section 41.5.3.1 of HI 41.5-2021 references Appendix E of HI 40.6-2021 as the test standard that governs measurements of all test points in the standard. DOE reviewed HI 40.6-2021 with respect to the minor modifications listed by the CPWG in Recommendation #10. DOE found that recommendations regarding frequency of data collection are included in section 40.6.5.5.1, and recommendations regarding electrical measurement equipment and power supply characteristics are included in section C.3.4.1 and Table 40.6.3.2.3. The recommendation regarding BEP speed—specifically, to test at max speed with no adjustment to nominal—is addressed in Appendix E of HI 40.6-2021, which excludes sections 40.6.5.5.2, 40.6.6.1, and 40.6.6.1.1, dealing with the specified speed of rotation and translation to that specified speed. The recommendations for relevant parameters at specific load points have been addressed in Appendix E of HI 40.6-2021 as well as HI 41.5-2021, with some modifications.

Id.

After considering stakeholder comments on the May 2021 RFI, DOE proposed to incorporate HI 40.6-2021, inclusive of Appendix E, into the proposed appendix D to subpart Y, with the exceptions, modifications, and additions described elsewhere in the December 2021 NOPR. DOE requested comment on its proposal. 86 FR 72096, 72121.

HI agreed with incorporating HI 40.6-2021 by reference. In Appendix E of HI 40.6-2021, HI noted exception and modifications for testing of circulator pumps. (HI, No. 9 at p. 6) Grundfos agreed with incorporating HI 40.6-2021 as stated in the December 2021 NOPR. (Grundfos, No. 7 at p. 4)

For the reasons discussed in the December 2021 NOPR and in the preceding paragraphs, DOE is incorporating by referencing HI 40.6-2021, inclusive of Appendix E, into appendix D to subpart Y, with the exceptions, modifications, and additions described elsewhere in the document.

2. Exceptions, Modifications and Additions to HI 40.6-2021

In the December 2021 NOPR, DOE stated that, in general, DOE finds the test methods contained within HI 40.6-2021 are sufficiently specific and reasonably designed to produce test results to determine a CEI that is representative of average use cycle of applicable circulator pumps. However, only certain sections of HI 40.6-2021 are applicable to the proposed circulator pump test procedure. 86 FR 72096, 72121. In addition, DOE proposed certain exceptions, modifications, and additions to ensure test results are sufficiently repeatable and reproducible, addressed in the subsequent sections III.E.2.a through III.E.2.d of this document.

a. Applicability and Clarification of Certain Sections of HI 40.6-2021

In the December 2021 NOPR, DOE stated that although it is proposing to incorporate by reference HI 40.6-2021 as the basis for its test procedure, some sections of the standard are not applicable to the circulator pump test procedure, while other sections require additional specification regarding their applicability when conducting the circulator pump test procedure.

Id.

DOE did not propose to adopt through reference section 40.6.4.1, “Vertically suspended pumps,” and section 40.6.4.2, “Submersible pumps,” of HI 40.6-2021 in the circulator pump test procedure because circulator pumps are IL pumps and are not vertical turbine or submersible pumps. As such, the test provisions applicable to vertical turbine and submersible pumps described in Section 40.6.4.1 and section 40.6.4.2 of HI 40.6-2021 would not apply to the circulator pump test procedure.

Id.

Additionally, Section 40.6.5.5.2 of HI 40.6-2021, “Speed of rotation during test,” requires that the speed of rotation to establish flow rate, pump total head, and power input be within the range of 80 percent to 120 percent of the rated speed. However, in the proposed circulator pump test procedure, rated or nominal speeds are not relevant, as DOE did not propose that speed be measured as part of the test procedure. Similarly, section 40.6.6.1, “Translation of test results to the specified speed of rotation,” describes the method by which tested data can be translated to the rated speed of rotation for subsequent calculations and reporting purposes. As DOE did not propose that speed be measured as part of this circulator pump test procedure, translation of tested results based on speed is not necessary. As a result, DOE did not propose to adopt Sections 40.6.5.5.2 and 40.6.6.1 (including 40.6.6.1.1) of HI 40.6-2021. This is consistent with the exclusions for circulator pump testing in Appendix E of HI 40.6-2021.

Id.

DOE also did not propose to adopt Section 40.6.5.3, “Test report,” which provides requirements regarding reporting of test results and Appendix B, “Reporting of test results,” that refers to DOE's existing reporting requirements at 10 CFR 429.59 for general pumps, both of which are not required for testing and rating circulator pumps in accordance with DOE's procedure. Specifically, the updated Appendix B references specific reporting requirements established in the general pumps test procedure, of which not all specifications are applicable to circulator pumps. DOE noted that it would propose specific certification and reporting requirements for circulator pumps as part of a separate rulemaking, should such standards be proposed.

Id.

For more information on any energy conservation standard rulemaking for circulator pumps see Docket No. EERE-2016-BT-STD-0004.

Finally, DOE did not propose to adopt Appendix G, “DOE compared to HI 40.6 nomenclature,” which refers to nomenclature used by DOE in the general pumps test procedure (appendix A to subpart Y of 10 CFR part 431) and is not in all cases consistent with the terminology used in the proposed circulator pump test procedure.

Id.

In summary, for the reasons stated previously, DOE did not propose to adopt Sections 40.6.4.1, 40.6.4.2, 40.6.5.3, 40.6.5.5.2, 40.6.6.1, 40.6.6.1.1, Appendix B, and Appendix G of HI 40.6-2021 as part of the DOE test procedure for circulator pumps.

Id.

In addition, DOE noted that Appendix E of HI 40.6-2021 includes modifications to testing in sections 40.6.5.5.1 and 40.6.6.3. DOE proposed to reference HI 40.6-2021 inclusive of Appendix E and the modifications therein.

Id.

DOE requested comments on these proposals.

Id.

Grundfos stated that excluding sections 40.6.4.1, 40.6.4.2, 40.6.5.3, 40.6.5.5.2, 40.6.6.1, 40.6.6.1.1, Appendix B, and Appendix G of HI 40.6-2021is warranted. (Grundfos, No. 7 at p. 4) HI stated that circulator pump definitions are separate from submersible or vertically suspended; therefore, a specific exclusion of Sections 40.6.4.1 and 40.6.4.2 is not needed. HI stated that Appendix E already excludes Section 40.6.5.5.2, 40.6.6.1, and 40.6.6.1.1, so DOE does not need to exclude them. HI agreed that Section 40.6.5.3, Appendix B, and Appendix G of HI 40.6-2021 can be excluded. (HI, No. 9 at p. 7)

In response to HI, DOE understands that within HI 40.6-2021 section 40.6.4, there are separate subsections for vertically suspended pumps (40.6.4.1), submersible pumps (40.6.4.2), and all other pump types (40.6.4.3), the latter of which references all other pump types identified by ANSI/HI 14.1-14.2, “Rotodynamic Pumps for Nomenclature and Definitions,” which is the successor to the previously discussed ANSI/HI 1.1-1.2-2014. DOE expects this is why HI stated that specific exclusion of sections 40.6.4.1 and 40.6.4.2 is not required. However, to provide clarity without having to reference additional industry standards, DOE is adopting only those specific sections of HI 40.6-2021 applicable to the test procedure for circulator pumps in scope of the DOE test procedure (see section A.0.1 in appendix D as established in this final rule), as proposed in the December 2021 NOPR. DOE is also excluding sections 40.6.5.5.2, 40.6.6.1, and 40.6.6.1.1, to improve the clarity of the DOE test procedure even though Appendix E of HI 40.6-2021 already excludes them. DOE is also adopting exclusions of section 40.6.5.3, Appendix B, and Appendix G as proposed in the December 2021 NOPR and supported by HI and Grundfos.

b. Testing Twin Head Circulator Pumps and Circulators-Less-Volute

In the December 2021 NOPR, DOE stated that a twin head circulator pump is a type of circulator pump that contains two impeller assemblies, mounted in two volutes that share a single inlet and discharge in a common casing. DOE proposed to test twin head circulator pumps as recommended by the CPWG and consistent with Section 41.5.3 of HI 41.5-2021. Specifically, DOE proposed that to test twin head circulator pumps, one of the two impeller assemblies should be incorporated into an adequate, single impeller volute and casing. An adequate, single impeller volute and casing means a volute and casing for which any physical and functional characteristics that affect energy consumption and energy efficiency are essentially identical to their corresponding characteristics for a single impeller in the twin head circulator pump volute and casing. DOE requested comments on its proposal. 86 FR 72096, 72121-72122.

HI agreed with the proposed test procedure for twin head pumps, which is consistent with the test procedure outlined in HI 41.5.3 (paragraph 5). (HI, No. 9 at p. 7) Grundfos agreed with the test method, stating that it is the same method applied to general pumps and using that test method ensures consistency in the regulation. (Grundfos, No. 7 at p. 4)

As discussed in the December 2021 NOPR and consistent with comment, in this final rule, DOE is adopting the test procedure for twin head circulator pump as proposed in the December 2021 NOPR.

In the December 2021 NOPR, DOE stated that a circulator-less-volute is a circulator pump with a complete motor that is sold without a volute, but for which a paired volute is available in commerce from a manufacturer. DOE proposed that the circulator-less-volute would be paired with specific volute(s)

with which the circulator-less-volute is offered for sale or advertised to be paired with, and that the combination would be subject to the proposed applicable DOE test procedure for that circulator-less-volute model. DOE proposed that the CEI for each volute and circulator-less-volute pairing be determined separately. Additionally, DOE proposed to allow manufacturers of circulator pumps to group similar volute and circulator-less-volute pairings within a given basic model rating to minimize testing burden, while still ensuring that the CEI rating is representative of minimum efficiency or maximum energy consumption of the group. DOE stated that circulator-less-volute manufacturers could opt to make representations of the CEI of each individual circulator-less-volute and volute combination or could elect to make CEI representations regarding a circulator-less-volute combined with several individual volutes and rate the group with the same representative CEI value, which would be representative of the least efficient model. DOE requested comment on its proposals. 86 FR 72096, 72122.

HI agreed with DOE's proposed test procedure for circulators-less-volute. (HI, No. 9 at p. 7) Grundfos agreed with the test procedure for circulator-less-volute but stated that header pumps should be included in this test procedure. (Grundfos, No. 7 at p. 4) As discussed in section III.B.4, Grundfos stated that DOE should require that header pumps be tested like circulators-less-volute, except that the manufacturer determines the volute to be used and make this volute available for testing on the open market so that all interested parties can purchase and test the pump in the same manner it was certified. (

Id.

)

As discussed in section III.B.4 and III.B.6 of this document, DOE is not including header pumps within the scope of the test procedure as it has determined that the recommended test method would increase burden and would not produce representative results. Therefore, for the reasons discussed in the December 2021 NOPR, DOE is adopting the test procedure for circulators-less-volute as proposed in the December 2021 NOPR.

c. Determination of Circulator Pump Driver Power Input at Specified Flow Rates

In the December 2021 NOPR, DOE proposed to adopt the provisions in appendix E of HI 40.6-2021 for determining circulator pump driver power input at specified flow rates, noting that these differ from the CPWG recommendations, but are more appropriate because having test points lower than the lowest point of required driver power allows a linear regression to be constructed that includes all the driver power input points. The provisions include:

• Section 40.6.5.5.1 Test procedure—A minimum of nine test points shall be taken for all performance tests. Points are to be selected at approximately 10 percent, 25 percent, 40 percent, 60 percent, 75 percent, 90 percent, 100 percent, 110 percent, and 120 percent of the flow rate at the expected BEP of the circulator pump.

• Section 40.6.6.3 Performance curve—Determine the pump total head versus flow rate curve only based on a polynomial of the 6th order.

• Section 40.6.6.3 Performance curve—Determine the driver power input at 25 percent, 50 percent, 75 percent, and 100 percent of BEP based on a 3rd order polynomial curve of best fit of the tested values (as specified in section 40.6.5.5.1) at 10 percent, 25 percent, 40 percent, 60 percent, 75 percent, 90 percent, 100 percent, 110 percent, and 120 percent of expected BEP flow rate.

DOE requested comments on this proposal. 86 FR 72096, 72122-72123.

HI and Grundfos agreed with DOE's proposal to incorporate Appendix E of HI 40.6-2021 for determining the circulator pump driver power input at flow rates. (HI, No. 9 at p. 7; Grundfos, No. 7 at p. 4) For the reasons discussed in the December 2021 NOPR and in the preceding paragraphs, in this final rule, DOE is incorporating Appendix E of HI 40.6-2021 into the test procedure for circulator pumps as proposed.

In the December 2021 NOPR, DOE also noted that the procedure specified in section 40.6.6.3 and Appendix E of HI 40.6-2021 is applicable for test points gathered at maximum speed, but the other test points proposed for circulator pumps with pressure controls, temperature controls, manual speed controls, and external input signal controls are not specified in HI 40.6-2016. For circulator pumps with pressure controls, temperature controls, manual speed controls, and external input signal controls, the general test procedure consists of “sweeping” the maximum speed curve (

i.e.,

taking measurements at flow intervals along the head/flow curve associated with maximum pump speed) to determine BEP, adjusting the pump to the determined BEP at maximum speed, and then adjusting the speed of the pump according to the applicable control or reference system curve to achieve the specified load points at 25, 50, 75 percent of BEP flow at reduced speed. As such, for these test points, unlike the test points at maximum speed derived from the data collected to determine BEP, manufacturers would adjust the operation of the pump to specifically achieve the load points at 25, 50, 75, and 100 percent of BEP flow, as applicable. Due to experimental uncertainty, the specific test points measured in the test protocol may not be exactly at 25, 50, 75, or 100 percent of the BEP flow load points specified in the test procedure and, thus, the relevant power input measurements must be adjusted to reflect the power input at the specific load points specified in the test procedure. DOE noted that HI 40.6-2021 does not specify the tolerances around which the specified flow values must be achieved or how to adjust the test points to the specified load points, accounting for such experimental tolerance. 86 FR 72096, 72123.

In the December 2021 NOPR, DOE stated that HI 41.5-2021 includes provisions different from those recommended by the CPWG. Specifically, all tested flow values must be within ±5 percent of the target flow load points as specified by the reference system curve in HI 41.5-2021. (HI 41.5-2021 section 41.5.3.4.2 #3c, 41.5.3.4.3, 41.5.3.4.4.1-2, 41.5.3.45) HI stated that this target range limits the pump efficiency ranges allowed for a given test point and minimizes variation in CEI values for a given test. In addition, any head values that are above the reference system curve (including within 10 percent) are not adjusted. HI stated that this eliminates a discontinuity in CEI values when transitioning between corrected and uncorrected values and allows for better representation of pump CEI. Finally, for pressure control and manual speed control, tested head is allowed to be below the reference curve and corrected back to the reference curve. HI stated that this eliminates the need for all control curves to exist above the reference curve allowing for a better representation of control curves used in the market and for the circulator pump CEI values to better represent a pump's capabilities. (HI, No. 112 at p. 2) These provisions are found throughout each of the individual control variety test methods in HI 41.5; a summary is available in 41.5.1. DOE proposed to incorporate the provisions in HI 41.5-2021. 86 FR 72096, 72123.

DOE noted also that the proposed load points are specified with a discrete flow value (

i.e.,

25, 50, 75, and/or 100 percent of BEP flow) and, for temperature control and external input signal controls, a minimum head value

(

i.e.,

at or above the reference system curve). Therefore, as proposed the flow values must be achieved within ±5 percent and, for temperature controls and external input signal controls, the tested head values must not be more than 10 percent below the reference system curve. Any test point with a flow value that is more than ±5 percent away from the specified value or, for temperature controls and external input signal controls, a head value is more than 10 percent below the reference system curve would be invalid and, therefore, must be retested. 86 FR 72096, 72124.

DOE proposed to adjust the tested driver input power values for all relevant test points for circulator pumps with temperature and external input signal controls using the methods adopted in the January 2016 TP final rule and discussed by the CPWG. Specifically, DOE proposed that if the tested flow values are within ±5 percent of the flow load point specified by the reference system curve and the head values are within ±10 percent of the head load points specified by the reference system curve, the tested driver input power values would be proportionally adjusted to the specified flow and head points, as shown in equation (12):

ER19SE22.027

Where:

R,i

= the driver power input (hp);

R,i

= the specified head at load point i based on the reference system curve (ft);

T,j

= the tested head at load point j (ft);

R,i

= the specified flow rate at load point i based on the reference system curve (gpm);

T,j

= the tested flow rate at load point j (gpm); and

T,j

= the tested driver power input at load point j (hp).

86 FR 72096, 72124.

DOE also proposed that for pressure controls and manual speed controls, if the tested flow values are within ±5 percent of the flow load point specified by the reference system curve and the tested head values are below the head load points specified by the reference system curve, the tested driver power input values would be proportionally adjusted to the specified flow and heat points as shown in equation (12).

Id.

Finally, DOE proposed, consistent with the recommendations of the CPWG and the modifications in HI 41.5-2021, that for temperature controls and external input signal controls, if the tested head values are above the reference system curve by more than 10 percent, or for pressure controls and manual speed controls, if the tested head values are above the reference system curve at all, only the flow values would be proportionally adjusted to the specified value, as shown in equation (13):

ER19SE22.028

Where:

R,i

= the driver power input (hp);

R,i

= the specified flow rate at load point i based on the reference system curve (gpm);

T,j

= the tested flow rate at load point j (gpm); and

T,j

= the tested driver power input at load point j (hp).

DOE requested comment on these proposals. 86 FR 72096, 72124.

HI stated that the power corrections in HI 41.5 are as HI intends, specifically for pressure and manual speed controls, the power corrections noted in HI 41.5-2021 section 41.5.3.4.2.3.d and Equation 41.5.3.4.2b for pressure speed control and section 41.5.3.4.5.2.d and Equation 41.5.3.4.5b for manual speed control. HI recommended that DOE should incorporate these sections by reference. (HI, No. 9 at p. 7) Grundfos also stated that only the head term is ignored when correcting power above the reference curve, and that it agreed with the ±5 flow tolerance. (Grundfos, No. 7 at p. 5)

HI stated that, with regard to temperature and external input signal controls, the power corrections noted in HI 41.5-2021 in section 41.4.3.4.3.2 and Equation 41.5.3.4.3b for temperature controls and sections 41.5.3.4.4.1.2 and 41.5.3.4.4.2.2 and Equations 41.5.3.4.4.1b and 41.5.3.4.4.2b for external input signal controls are as intended. HI recommended that DOE should incorporate these sections by reference. (HI, No. 9 at p. 8) Grundfos reiterated that only the head term is ignored when correcting power above the reference curve, and that it agreed with the ±5 flow tolerance. (Grundfos, No. 7 at p. 5)

For the reasons discuss above and in the December 2021 NOPR, DOE is adopting the flow and head tolerances and proportional adjustments as proposed in the December 2021 NOPR. However, as discussed in section II, DOE is adopting through reference specific sections of HI 41.5-2022, each of which includes provisions for these adjustments. The language in HI 41.5-2022 differs from that in the regulatory text in the December 2021 NOPR, by using only one equation and clarifying the applicable use of the equation in different scenarios in text rather than including two separate equations applicable to the different scenarios as DOE did. However, the substance of the language in HI 41.5-2022 is consistent with that of the regulatory text in the December 2021 NOPR; as such this does not represent a substantive change. In addition, HI specifically requested DOE reference the relevant sections of HI 41.5-2021 (to which HI 41.5-2022 is identical), and no stakeholders expressed that the relevant language in HI 41.5 was unclear.

With regards to the test points to which the tolerance and adjustment methods are applicable, DOE noted in the December 2021 NOPR that the CPWG recommended that “all” test points for circulator pumps with pressure controls, temperature controls, manual speed controls, or external input signal controls apply the specified tolerances and adjustment methods. (Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendation #10 at pp. 8-9) However, DOE stated that it believed that the curve fitting method for determining driver power input at the specified load points at maximum speed is more applicable and less burdensome for many of the maximum speed test points than requiring retesting along the maximum speed curve to achieve those test points within ±10 percent. Specifically, for manual speed controls and external input signal controls in addition to other control varieties, the proposed test methods and CEI calculation methods require load points be determined at 25, 50, 75, and 100 percent of BEP flow along the maximum speed curve, as well as at 25, 50, and 75 percent of BEP flow at reduced speeds. For the test points at reduced speed, DOE stated that it believed, as recommended by the CPWG, that the proposed tolerances and proportional adjustment would be applicable. However, for the test points at 25, 50, and 75 percent of maximum speed, DOE stated that it believed that it would be less burdensome and more consistent with the proposed testing of circulator pumps with no controls to determine such test points via curve fitting of the BEP test data at maximum speed. DOE stated that this is consistent with Sections 41.5.3.4.4.2 and 41.5.3.4.5 of HI 41.5-2021. With regard to the test point at 100 percent of BEP flow and maximum speed, DOE noted that, in order to test such circulator pump models, the circulator pump must be adjusted to a test point at 100 percent of BEP flow and maximum speed before reducing the speed in accordance with the control logic to achieve the reduced speed values. As such, DOE stated that using the tested value at 100 percent of BEP flow and maximum speed as opposed to the value determined via curve fitting would be more accurate and would not increase the burden of the testing. DOE noted that this proposal is inconsistent with HI 41.5-2021, which includes the 100 percent point as part of the points determined by curve fitting, rather than as a measured test point. DOE requested comment on this deviation. 86 FR 72096, 72124-72125. Table III.2 summarizes the proposed applicability of the different adjustment methods to the various test points for each circulator pump variety.

Table III.2—Summary of Applicable Adjustment Method for Different Test Points for All Control Varieties

Control variety

Test points that would be determined via curve fitting

Test points that must be achieved within any

specified tolerance and would be determined via

proportional adjustment

Pressure Controls

None

All (25, 50 ,75, and 100 percent of BEP flow).

Temperature Controls

None

All (25, 50 ,75, and 100 percent of BEP flow).

Manual Speed Controls

25, 50, and 75 percent of BEP flow at maximum speed

25, 50, and 75 percent of BEP flow at reduced speed and 100 percent of BEP flow at maximum speed.

External Input Signal Controls

25, 50, and 75 percent of BEP flow at maximum speed

25, 50, and 75 percent of BEP flow at reduced speed and 100 percent of BEP flow at maximum speed.

DOE requested comment on the proposed applicability of the tolerance and proportional adjustment method to the various test points, as compared to the curve fitting method, based on circulator pump control variety. DOE particularly requested comment on which category is most appropriate for the 100 percent of BEP flow point.

Id.

at 86 FR 72125.

HI stated that it understood that DOE proposed to test the 100 percent BEP for manual speed controls and external input signal controls the same way as for pressure and temperature controls to determine the input power term at maximum speed in the CER equation, which requires adjusting the tested power proportional to the BEP originally determined from the curve fit. HI commented that the curve fitted 100 percent BEP point is the anchor point for the reduced speed load points and should be used without requiring retesting for manual and external input speed control. HI stated that DOE's proposal would not increase accuracy but would require retesting a point already measured. HI stated that DOE should incorporate by reference the language in sections HI 41.5.3.4.5 for manual speed control and 41.5.3.4.4 for external input signal control to maintain consistency with what industry has already implemented. (HI, No. 9 at p. 8)

Grundfos stated that maintaining the curve fitting method is preferable to minimize testing burden even if minor deviations are present using this method. Grundfos added that if DOE decides that curve fitting error needs to be addressed, allowing a piece-wise curve fitting would solve this issue. Grundfos added that this curve fitting error happens at all test points, not just at 100 percent BEP. (Grundfos, No. 7 at p. 5)

DOE agrees with HI and Grundfos that deviating from HI 41.5-2021 to require the 100 percent BEP flow point be obtained by achieving the test point within tolerance rather than by curve-fitting would introduce burden not warranted for the expected gain. These provisions appear in the updated version of the industry guideline, in HI 41.5-2022 sections 41.5.3.4.5 and 41.5.3.4.4, which DOE is adopting through reference. As such, DOE is adopting provisions for manual speed controls and external input signal controls that determine the 100 percent BEP flow point through curve fitting.

3. Calculation and Rounding Modifications and Additions

In the December 2021 NOPR, DOE noted that HI 40.6-2014 did not specify how to round values for calculation and reporting purposes. DOE recognized that the manner in which values are rounded can affect the resulting CEI and that CEI values should be reported with the same number of significant digits. Therefore, to improve the consistency of calculations and to ensure accuracy, the CPWG recommended that that all calculations be performed with the raw measured data, and that the resultant CER (then called PER

CIRC

)and CEI (then called PEI

CIRC

) be rounded to 3 significant figures. (Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendation #10 at p. 8) DOE noted that neither HI 40.6-2021 nor HI 41.5-2021 include any rounding provisions. 86 FR 72096, 72125.

DOE stated that it agreed with the CPWG regarding its recommendation to perform all calculations with the raw measured data and to round the resultant CER, CEI, and other relevant measurements and calculations in a standardized manner. In the established provisions for general pumps, the CEI analog (“PEI”) is rounded to the nearest hundredths place (

i.e.,

0.01). See section I.D.3 of appendix A to subpart Y of part 431. To be consistent with the general pumps provisions, DOE proposed to round CER to three significant figures and to round CEI to the nearest hundredths place. Additionally, DOE proposed to calculate relevant non-energy metrics using the raw measured data and to round to the following: BEP flow at maximum speed and BEP head at maximum speed values to three significant figures; real power, true RMS current, and true RMS voltage values to the tenths place (

i.e.,

0.1); and rated hydraulic horsepower and true power factor values to the hundredths place unless otherwise specified. DOE requested comment on these proposals.

Id.

at 86 FR 72125-72126.

HI agreed with using raw data for all calculations. HI stated that it is common practice for manufacturers to use power analyzers to measure the real power input and that individual values of RMS voltage, RMS current, and true power factor are not always available. HI added that collection of test data to 3 significant digits could be a problem depending on instrumentation display, its resolution, and the measured value. (HI, No. 9 at p. 9)

HI agreed with the CPWG recommendation that any non-energy metrics, like RMS current, RMS voltage, real power, and power factor, should be voluntary to report. (HI, No. 9 at p. 9) HI stated that, for voluntary purposes to DOE, sufficient rounding guidelines are as follows:

• Flow at maximum speed (Three significant digits, but limited to the tenths place for decimal values.

e.g.,

101, 10.1, 1.1)

• BEP head at maximum speed (Three significant digits, but limited to the tenths place for decimal values.

e.g.,

101, 10.1, 1.1)

• Real power (Three significant digits, but limited to four decimal places.

e.g.,

0.0111)

• True RMS current (Three significant digits, but limited to the tenths place for decimal values.

e.g.,

101, 10.1, 1.1)

• True RMS voltage (Tenths)

• Hydraulic horsepower (Three significant digits, but limited to four decimal places.

e.g.,

0.0111)

• True power factor (Hundredths place)

(

Id.

)

HI added that the rounding guidelines should not apply to manufacturer representations of this data in commerce (

e.g.,

websites, literature). (

Id.

)

Grundfos agreed that the calculations should be done using raw measured data and agreed with the recommendations from HI on rounding. (Grundfos, No. 7 at p. 5)

In response to HI's and Grundfos' comments in support of the CPWG's recommendation to use unrounded values in intermediate test procedure calculations, DOE is adopting in the December 2021 NOPR proposal to use the raw measured data in this final rule. Specifically, DOE is requiring use of raw measured data to perform test procedure calculations.

In response to HI's support of rounding provisions only as related to voluntary reporting to DOE and not to manufacturer representations, DOE has determined that as it has not yet proposed or finalized certification reporting requirements for circulator pumps, it is only appropriate to finalize rounding proposals related to parameters necessary for determination of scope (

i.e.,

rated hydraulic horsepower) and calculation of CEI (

i.e.,

CER, BEP flow, and BEP head). As DOE has not yet determined whether it is necessary to report real power, RMS voltage, RMS current, and true power factor, and given HI's statement regarding potential limitations in instrumentation for these values, DOE finds that it would be premature to finalize rounding proposals related to these provisions at this time. DOE may consider certification reporting requirements in a separate rulemaking.

Specifically to CEI and CER, DOE received no comments or data contrary to adoption of the December 2021 NOPR proposal. Therefore, DOE is adopting in this final rule the December 2021 NOPR's proposal to require rounding of (1) CEI to the hundredths decimal place; and (2) CER to three significant figures. Rounding CER to three significant figures is consistent with the CPWG's recommendation and rounding CEI to the hundredths place is consistent with the requirements for general pumps.

See

section I.D.3 of appendix A to subpart Y of part 431.

Regarding rated hydraulic horsepower, HI and Grundfos suggested more precision than DOE proposed requiring in December 2021 NOPR's proposal. Whereas the December 2021 NOPR proposed to require rounding of rated hydraulic horsepower to the hundredths decimal place,

as stated previously HI (and Grundfos in support of HI's comment) commented in support of rounding to three significant figures, not to exceed four decimal places. (HI, No. 9 at p. 9; Grundfos, No. 7 at p. 5)

For this discussion of rated hydraulic horsepower, decimal places are as expressed in units of horsepower.

Review of publicly available marketing literature indicates availability of units of power draw at least as small as 14W.

Depending on the relative efficiencies of both the motor and wet end, DOE estimates the rated hydraulic horsepower of such a motor may round to zero if expressed to two decimal places.

Xylem Inc.

Autocirc Instant Hot Water System Product Brochure.

Accessed: June 07, 2022.

https://www.xylem.com/siteassets/brand/bell-amp-gossett/resources/brochure/a-134.pdf.

Further, because circulator pump motor output power is often marketed using fractions, identifying the correct value when converted to decimal notation would require at least the same number of significant figures. As the denominators of circulator pump motor output power reach at least three digits, at least three significant figures are required to identify rated hydraulic power with sufficient precision. However, in review of the market, DOE did not observe circulator pump models, which would require more precision than the fourth decimal place to characterize.

Accordingly, in this final rule, DOE is adopting the rounding requirements suggested by HI and supported by Grundfos to round rated hydraulic power to less precise of the following two values: three significant figures; the fourth decimal place when expressed in units of horsepower.

4. Rated Hydraulic Horsepower

In the December 2021 NOPR, DOE noted that the proposed definitions of dry rotor, two-piece circulator pumps and dry rotor, three-piece circulator pumps each contain a clause that the pump must have a rated hydraulic power less than or equal to 5 hp at BEP at full impeller diameter. Accordingly, DOE proposed nomenclature to consistently refer to and categorize dry rotor circulator pumps based on the hydraulic horsepower they can produce at BEP and full impeller diameter, as measured in accordance with the proposed circulator pump test procedure. DOE noted that hydraulic horsepower (termed pump power output

) is defined in HI 40.6-2021

and which DOE proposed to adopt through reference (

see

section III.E.1 of this document). HI 40.6-2021 also contains a test method for determining pump power output. However, HI 40.6-2021 includes methods for determining pump power output at any load point. To specify the pump power characteristic that DOE proposed to use to describe the size of dry rotor circulator pumps, DOE proposed to introduce a new term, the “rated hydraulic horsepower,” that is identified as the measured hydraulic horsepower at BEP and full impeller diameter for the rated pump. DOE requested comment on this proposal. 86 FR 72096, 72126.

The term “pump power output” in HI 40.6 is defined as “the mechanical power transferred to the

liquid as it passes through the pump, also known as pump hydraulic power.” It is used synonymously with “hydraulic horsepower” in this document. However, where hydraulic horsepower is used to reference the size of a dry rotor circulator pump, it refers to the rated hydraulic horsepower.

HI agreed with the proposal to use rated hydraulic horsepower. (HI, No. 9 at p. 9) Grundfos agreed with the proposal but stated that DOE needs to consider that using rated hydraulic horsepower could modify the scope of products covered by the CPWG recommendations. Grundfos also noted that consideration should be made to ensure that setting this limit does not modify the scope such that wet runner

and dry runners

have different sizes covered by the regulation. (Grundfos, No. 7 at pp. 5-6)

Also known as wet rotor circulator pumps.

Also known as dry rotor circulator pumps.

In response to Grundfos, the definitions for the two varieties of dry rotor circulator pumps, as recommended by CPWG, as proposed in the NOPR, and as found in HI 41.5-2021, specify that such pumps must have hydraulic power less than or equal to five horsepower at best efficiency point at full impeller diameter. DOE's proposed test procedure in section 7 of appendix D requires determination of the rated hydraulic horsepower as the pump power output measured at BEP and full impeller diameter for the rated pump. This provision does not differ materially from the language in the dry rotor circulator pump definitions. As such, DOE has determined that the definition will not modify the scope of products covered by the CPWG recommendations. In addition, the proposed definition of wet rotor circulator pump does not have such a horsepower limitation provision because, unlike dry rotor circulator pumps, wet rotor circulator pumps are not found in larger horsepower that would otherwise be regulated as a commercial and industrial pump. For these reasons, DOE is adopting the provision for rated hydraulic horsepower as proposed in the December 2021 NOPR.

F. Samp

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