# OBSOLETEC.’



# 1985 TO KEHI TCPCIRM 0 AREA 

# STANDARDfor GROUND WATER-SOURCE NEAT PUMPS



# I Standard 325

AIR-CONDITIONING AND 1501 WILSON BOULEVARD REFRIGERATION INSTITUTE

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### ARLINGTON, VIRGINIA 22209

I I’.j) L..’

# OBSOLETE

TCI

TABLE OF CONTENTS

PART PAGE

Section 1. Purpose 1 Section 2. Scope 1 Section 3. Definitions 1 Section 4. Classification 2 Section 5. Testing and Rating Requirements 2 Section 6. Performance Requirements 4 Section 7. Safety Recominendation 6 Section 8. Conformance 6



# PROPERTY OF U.S. GOVERNE’ TARI STANDARD 325-85 

# GROUND WATER-SOURCE HEAT PUMPS

Section 1. Purpose 1.1 Purpose. The purpose ofthis standard is to estab lish, for ground water-source heat pumps: definitions and classification; requirements for testing and rating; specifications, literature and advertising requirements; performance requirements; safety requirements; and conformance conditions. 1.1.1 This standardis intended forthe guidance of the industry, including manufacturers, distributors, consultants, contractors, and consumers 1.2 ReviewandAmendment. This standardis subjectto review and amendment as the art of the industry ad vances. 

### Section 2. 

### Scope 2.1 Scope. This standard applies to factory-made resi dential, commercial, andindustrialgroundwater-source heat pumps, as defined in 3.1. 2.1.1 Energy Source. This standard applies only to electrically-driven, mechanical compression type systems. 2.2 Exclusions. This standard does not apply to the rating and testing ofindividual assemblies for separate use. 2.2.1 This standard does not applyto water-source heat pumps as defined in ART Standard 320.



### Section 3. Definitions 3.1 Ground Water-Source Heat Pump. A ground water-source heat pump consists of one or more factory-made assemblies which normally include an in doorconditioning coilwith airmoving means, compres sor(s) and refrigerant-to-water heat exchanger(s), in cluding means to provide a heating function and may include a cooling function. When such equipment is provided in more than one assembly, the separated as semblies shall be designed to be used together, and the requirements ofratingoutlinedinthestandardarebased upon the use ofmatched assemblies. 3.1.1 Functions. Groundwater-sourceheatpumps shallprovidethefunction ofheatingwithcontrolled temperature, and may include the functions ofaircooling, air-circulating, air-cleaning, dehumidifying or humidifying. 3.2 Published Rating. A statement of the assigned values of those performance characteristics, under stated rating conditions, by which a Unit may be chosen tofitits application. Thesevalues applyto allunits oflike nominal size and type (identification) produced by the same manufacturer.As usedherein, theterm“published rating” includes the rating of all performance charac teristics shown on the heatpump orpublishedin specifi cations, advertising, orotherliterature controlledby the manufacturer, at stated rating conditions. 3.2.1 StandardRating. Arating based on tests per formed at Standard Rating Conditions. 3.2.2 Application Rating. A rating based on tests performed at application rating conditions (other than Standard Rating Conditions). 3.3 Rating Conditions. Any set ofoperating conditions under which a single level ofperformance results, and which causes only that level ofperformance to occur. 3.3.1 Standard Rating Conditions. Rating condi tions used as the basis of comparison of perfor mance characteristics. 3.4 Energy Efficiency Ratio (EER). A ratio calculated by dividing the cooling capacity in Btuh by the power input in watts at any given set ofrating conditions, ex pressed in Btuh per watt (Btuh/watt). 3.4.1 Standard Energy Efficiency Ratio. A ratio calculatedfromthe capacity andpowerinputvalues obtained at Standard Rating Conditions. 3.5 Coefficient ofPerformance (COP). A ratio calcu lated by dividing the total heating capacity provided by the refrigeration system including circulating fan heat but excluding supplementary resistance heat, (Btuh) by the total electricalinput (watts) x 3.412. [A ratio calcu lated forboth cooling and heating capacities by dividing capacity in watts by power input in watts.] 3.5.1 Standard CoefficientofPerformance. Aratio calculated from the capacity and power input ob tained in accordance with 3.5 at Standard Rating Heating Conditions. 3.6 “Shall”, “Should”, “Recommended”, or “Itis Rec ommended”. “Shall”, “should”,”recommended”, or“it is recommended” shall be interpreted as follows: 3.6.1 Shall. Where “shall” or “shall not” is used for a provision specified, that provision is manda tory ifcompliance with the standard is claimed. 3.6.2 Should, Recommended, or It is Recom mended. “Should”, “recommended”, or “it is rec ommended” isusedtoindicateprovisionswhichare not mandatory but which are desirable as good practice. 1ARI STANDARD 325-85.

Section 4. Classification 4.1 Classification. Normally, ground water-source heat pumpswithinthe scopeofthis standardmaybe classified

as shown in Table 1.

Section 5. Testing and Rating Requirements 5.1 Standard Rating. Standard ratings shall be estab lished at the Standard Rating Conditions specified in 5.1.4. All standardratings shall be verifiedby tests con ducted in accordance with the ASHRAE Standard Methods ofTestingforRating UnitaryAir-Conditioning andHeatPump Equipment (American Society.ofHeat ing, Refrigerating andAir-Conditioning Engineers, Inc. Standard 37-78), and with the test methods and proce dures as described in this standard.
Standard Ratings relating to cooling or heating capacities shall be net values, including the effects of circulating-fan heat, but not including supplementary heat. Power input shall be the total power input to the compressor(s) and fan(s), plus controls and otheritems included as part ofthe model number(s).
Standard Ratings of units which do not have indoor air-circulating fans furnished as part ofthe model, i.e., splitsystemwithindoorcoil alone (seeTable 1), shallbe established by subtracting from the total cooling capac ity 1,250 Btuh/1000 cfm [0.78 watts perils], and by adding the same amount to the heating capacity. Total power input for both heating and cooling shall be in creased by 365 watts/1000 cfm [0.78 watts per Us] of indoor air handled. 5.1.1 Values ofStandard Capacity Ratings. These ratings shall be expressed only in terms ofBtu per hour (Btuh) [watts] in multiples of: Capacities (Btuh) [W] Less than 20,000 [5,9001 20,000-37,800 [5,900-11,000] 38,000-64,500 [11,100-18,900] 65,000 and above [19,000

and above] 5.1.2 Values ofPressure Drop Ratings. Waterflow rate(s) andpressure drop(s) shall be determined at each Standard Rating Condition specified in 5.1.4. Waterpressure drop through the unit for the rated standardflowrate(s) shallbe expressedinmultiples of 0.5 pounds per sq in (psi [3.5 kPa]. Waterfiow rate(s) shallbeexpressedingallonsperminute [L’s] in multiples of0.1 gpm to 10 gpm and 0.5 gpm for
over 10 gpm [0.01 Us tà I Us and 0.05 Us over 1 Us].Units suppliedwithwatercontrolvalveshallbe tested with the valve wide open. 5.1.3 Values ofStandard Energy Efficiency Ratios
or Coefficients ofPerformance. Standard ratios of energy efficiency for cooling, whenever published, shall be expressed in multiples of the nearest 0.1 Btuhlwatt [cooling COP in multiples of0.11; stan dard coefficients of performance for heating, wheneverpublished, shall be expressedin multiples ofthe nearest 0.1. In calculating EER’s or COP’s, a penalty for the water pump effect shall be added to the measured powerinput and determined as follows: PP =WF [(PPB x P) + 65) where PP = total pumping penalty, in watts [‘NJ WF = waterflow rate, in gallons per minute [L/s] PPB = basic pumping penalty (Table 2), in watts/gpmper .P inpsi [watts/(Us) per P in kPa]

= unit waterpressure drop, in psi [kPa] 65 [1030] = constant, in watts per gpm [wattsper L/s] based on 50 ft [15.24 m] external head Example: At rated flow of 10 gpm [0.631 Us], from Table 2 PPB = 2.69 watts/gpm per P in psi [watts/(L/s) perP in kPa] With water coil pressure drop = 10 psi [68.9 kPa] PP 10 [(2.69 x 10) + 65] = 919 watts [919 watts] 5.1.4 Standard Rating Conditions. The conditions oftestforStandard Ratings shall include the follow ing: Multiples (Btuh) [W] 100 [30] 200 [60] 500 [160] 1000 [300]



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Table 1. Classification ofGround Water-Source Heat Pumps Types ofGround Water.Source Heat Pumps

+ARI Type Designation Heating Heating *Arrangement and Cooling Only Single Package HSP.GW HOSP-GW FAN COMP1 EVAP CONDI Split System HRCU- HORCU- FAN COMP

• GW-CB GW-CB IEVAP COND Split System with HRCU- HORCU- COMP No Indoor Fan GW-C GW-C IEVAPI COND
+A suffix of“-O”following any ofthe above classifications indicates equipmentnotintended foruse with field-installed duct systems (See 5.1.4.5).

- Denotes cooling mode function. S

2ARt STANDARD 325-85

Table 2. Basic Pumping Penalty PPB vs. WF WF (Watts/gpm [Watts/(LIs) (gallons per per P per

minute) (Usl in psi) in kPaJ 1

- 4.0 0.063

- 0.252 5.00 11.50 4.1

- 7.9 0.258

- 0.498 3.88 8.92 8.0- 12.9 0.504

- 0.750 2.69 6.19 12.0

- 15.9 0.757

- 1.002 2.32 5.34 16.0- 19.9 1.010- 1.254 2.14 4.92 20.0 and above 1.262 and above 2.02 4.65

5.1.4.1 Standard Rating Temperatures.

a. Cooling (High Temperature) (Not required for heating-only units) Air temperature entering indoor portion of unit 80F[26.7°Cj dry bulb, 67F[19.4°C] wet bulb Air temperature surrounding unit 80F[26.7°CJ dry bulb Water temperature entering refrigerant-towater heat exchanger 70F[21.1°C} Water flow rate as specified by manufacturer b. Cooling (Low Temperature) (Not required for heating-only units) Air temperature entering indoor portion of unit 80F[26.7°CJ dry bulb, 67F[19.4°C] wet bulb Air temperature surrounding unit 80F[26.7°C] dry bulb Water temperature entering refrigerant-towater heat exchanger 50F[10°CJ Water flow rate as specified by manufacturer

c. Heating (High Temperature) Air temperature entering indoor portion of unit 70F[21.1°CJ dry bulb, 60F[15.6°C] wet bulb, max. Air temperature surrounding unit 70F[21.1°Cj dry bulb Water temperature entering refrigerant-towaterheat exchanger 70F[21.1°C} Water.flow rate as specified by manufacturer d. Heating (Low Temperature) Air temperature entering indoor portion of unit 70F[21.1°Cj dry bulb, 60F{15.6°C] wet bulb, max. Air temperature surrounding unit 70F[21.1°Cj dry bulb Water temperature entering refrigerant-towater heat exchanger 50F[10°Cj Water flow rate as specified by manufacturer 5.1.4.2 Electrical Conditions. Recommended nameplate voltages for 60 Hertz systems are one ormore ofthe utilizationvoltages showninTable 1 ofARI Standard 110 forAir-Conditioning and Refrigerating EquipmentNameplate Voltages. Standard Rating tests shall be performed at the nameplate rated voltage(s) and frequency. For heat pumps with dual nameplate voltage ra tings, Standard Rating Tests shall be performed at both voltages, or at the lower of the two vol tages, if only a single Standard Rating is to be published. 5.1.4.3 Indoor-Side Air Quantity. All Standard Ratings shall be determined at an indoor-side air quantity, delivered against at least the minimum external resistance required by 5.1.4.5, as out lined below. All air quantities shall be expressed as cfm [L/sJ of standard air (density 0.075 lb per cu ft [1.2 kg!m 3 1). a. Heat pumps shall be rated at the indoor-side air quantity delivered when operating against the minimum external resistance specified in 5.1.4.5 or at a lower indoor-side air quantity, ifso specified by manufacturer. b. Heat pumps which do not incorporate an in door fan, but are rated in combination with a device employing a fan shall be rated as de scribedundera. above. Forheatpumps ofthis class which are rated for general use to be applied to a variety ofheating plants, the in door-side air quantity shall be as specified by the manufacturer in his standard ratings, or the air quantity obtained through the indoor coil assembly when the pressure drop across the indoor coil assembly and the recom mended enclosures and attachment means is not greater than 0.30 inches of water [74.7 Pa], whichever is less. Indoor-side air quantities as referred to herein apply to the air quantity experienced when the unitis cooling and dehumidifying underthe Stan dard High Temperature Rating Cooling Condi tions specified in this section. Heating-only units shall use the air quantity experienced when the unit is operating under the Standard High Tern perature Heating’ Rating Conditions. This air quantity, except as noted in 6.3, shall be em ployedin all othertestsprescribed herein without regard to resulting external static pressure. 5.1.4.4 Requirementsfor SeparatedAssemblies. All Standard Ratingsforheatpumps in which the outdoor sectionis separated from the indoor sec tion, asinTypeHRCU (shownin Section4), shall be determined with at least 25 feet [7.62 nil of 3ARI STANDARD 325-85.

interconnection tubing on each line, of the size recommended by the manufacturer. Such heat pumps in which the interconnectiontubing is fur nished as an integral part of the machine not recommendedforcuttingto length shall be tested with the complete length oftubing furnished, or with 25 feet [7.62 m] of tubing, whichever is greater. The line sizes, insulation, and details of installation shallbein accordance withthe manu facturer’s published recommendations. 5.1.4.5 Minimum External Resistances. Indoor air-moving equipmentintendedforuse with field installed duct systems shall be designed to oper ate against, and tested at not less than, the minimum external resistance shown in Table 3 when delivering the rated capacity and air quan tity specified in 5.1.4.3. Indoor air-moving equipment not intended for use with field in stalled duct systems shall be tested at 0 in. water [0 Pa] external pressure. In interpreting this requirement, it is understood that the most restrictive filters, supplementary heating coils, and other equipment recom mended as optional parts ofthe heatpump be in place and that the net external resistances specified above are availableforthe external duct system. 5.2 Part-LoadRating. Heatpumps which are capable of capacity control shall be rated at each step of capacity reduction provided by the heat pump, and allowed by the controls. 5.2.1 Part-Load Rating Conditions (Cooling and Heating). The conditions oftest for part-load rat ings are the same as for the Standard Ratings (see 5.1). The capacity reduction means may be ad justed to obtain the specified step of unloading. Automatic adjustment of water flow rate by sys tern function is permissible. 5.3 Application Ratings. Ratings at conditions ofair or water temperature or air or water quantity other than those specified in 5.1.4 and 5.2.1, may be published as application ratings, and shall be based on data deter mined by the methods prescribed in 5.1. 5.4 Publication ofRatings. Wherever application ra tings are published or printed, they shall include, or be accompanied by, the Standard Capacity Ratings and their Standard Energy Efficiency Ratios or Coefficients ofPerformance, clearly designated as such, including a statement ofthe conditions at which the ratings apply. 5.4.1 Capacity Designation. Thecapacitydesigna tion used in published specifications, literature or advertising, controlled by the manufacturer, for heat pumps rated under this standard, are to be Table 3. Minimum External Resistance
Minimum External Standard Cooling Capacity Ratings Resistance (Inches of (Thousands ofBtuh) [kWJ Water) [Pa] Up thru 28.8 Up thru 8.4 0.10 24.9 29 thru 42.5 8.5 thru 12.5 0.15 37.4 43 thru 70 12.6 thru 20.5 0.20 49.8 71 thru 105 20.8 thru 30.8 0.25 62.3 106 thru 134 31.1 thru 39.3 0.30 74.7 135 thru 210 39.6 thru 61.6 0.35 87.2 211 thru 280 61.7 thru 82.1 0.40 99.6 281 thru 350 82.2 thru 102.6 0.45 112.1 351 thru 400 102.7 thru 117.2 0.55 137.0 401 thru 500 1 17.3 thru 146.6 0.65 161.9 501 and over 146.7 and over 0.75 186.8 expressed only in Btuh [watts] at the Standard Ra ting Conditions specified in 5.1.4 and in the terms describedin 5.1.1 through 5.1.3. Horsepower, tons or otherunits shall not be used as capacity designa tions. 5.5 Tolerances. To comply with this standard, pub lished cooling capacity ratings, heating capacity ratings, ratios ofenergy efficiencyforcooling, andcoefficients of performanceforheating, shallbebasedondataobtained in accordance with the provisions of this section, and shall be such that any production unit, when tested, will meet or exceed these ratings except for an allowance to cover testing variations; the amount of allowance to be minus 5 percent.

Section 6. Performance Requirements 6.1 Performance Requirements. To comply with this standard, ground water-source heat pumps shall be de signed and produced in accordance with the provisions ofthis section in such a mannerthat any production unit will meet the requirements detailed herein. 6.2 Maximum Operating Conditions Test. Ground water-source heat pumps shall be designed and pro duced to pass the following maximum operating condi tions test with an indoor side coil air quantity as deter mined under 5.1.4.3: 6.2.1 Temperature Conditions.

6.2.1.1 Cooling (Not required forheating-only units) Air temperature surrounding unit 80 F [26.7°C] dry bulb Air temperature entering indoor portion ofunit 80 F [26.7°C] dry bulb, 67 F [19.4°C] wet bulb Water temperature entering refrigerant

to-water heat exchanger 75 F [23.9°C] 

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I

CARI STANDARD 325-85

Water flow rate

. ... Maintained at 90 percent offlow rate specified in high temperature cooling test of 5.1.4.la 6.2.1.2 Heating. Air temperature entering indoor

portion ofunit 70 F [21.1°C] dry bulb Air temperature surrounding unit 70F[21.1°C]drybulb Water temperature entering refrigerantto-water heat exchanger 75 F [23.9°C] Water flow rate

.. . Maintained at 110 percent offlow rate specified in high temperature heating test of5.1.4.lc 6.2.2 Voltages. Tests shall be run at the Range A minimum utilization voltage from ARI Standard 110, Table 1, based upon the unit’s nameplate rated voltage(s). This voltage shall be supplied at the unit’s service connection and at rated fre quency. 6.2.3 Procedure. Theheatpump shallbeoperated for one hour at the temperature conditions and voltage specified. 6.2.4 Requirements. The heatpump shall operate continuously without interruption for any reason for one hour. 6.3 Voltage Tolerance Test. Ground water-source heat pumps shall be designed and produced to pass the fol lowingvoltagetolerance testwith acoolingcoil airquan thy as determined under 5.1.4.3. 6.3.1 Temperature Conditions. Temperature con ditions shallbemaintainedas shownin 5.1.4. la (or in 5.1.4.lc for heating-only units). 6.3.2 Voltages.

6.3.2.1 Tests shall be run at the Range B minimum and maximum utilization voltages from ART Standard 110, Table 1, based upon theunit’s nameplateratedvoltage(s).Thesevol tages shall be supplied at the unit’s service con nection and at rated frequency. A lower or a higher voltage shall be used, if listed on the nameplate. 6.3.2.2 The power supplied to the heat pump shall be adjusted just prior to the shut down period (See 6.3.3.2) so thattheresultingvoltage at the unit’s service connection is 86 percent of nameplate ratedvoltage when the compressoris on locked rotor. For the purpose of this stan dard, the compressor nameplate locked-rotor amperes may be used to determine this voltage. The proper value ofno-load voltage which will give the specified voltage at locked-rotor condi tions should be determined priorto the test. The locked-rotor current value of any motor shall be measured as follows: a. All hermetic compressor motors shall be tested as a compressor assembly. b. The motorwinding temperature shall not exceed 77 F [25°C] when the voltage is applied. c. The currentreading shall be taken within four seconds after the voltage is applied. Ifthe test is repeated, the motor winding shall be allowed to cool to 77 F [25°C] or lower before the currentis reapplied. d. The voltage at the unit service connec tion, at the time the current reading is taken, shall be the manufacturer’s name plate rated voltage. e. The locked-rotor current shall be mea sured with an ammeter, with the rotor actually locked. 6.3.2.3 Within one minute afterthe heatpump has resumed continuousoperation (see 6.3.4.3), the voltage shall be restored to the values specified in 6.3.2.1. 6.3.3 Procedure.

6.3.3.1 The heat pump shall be operated for one hour atthe temperature conditions andvol tage(s) specified. 6.3.3.2 Allpowerto the heatpump shall be cut offfor a period sufficient to cause the compres sorto stop (notto exceedfive seconds) and then restored. 6.3.4 Requirements.

6.3.4.1 Duringboth entire tests, the heatpump shall operate without failure ofany ofits parts. 6.3.4.2 The heat pump shall operate continu ouslywithoutinterruptionforanyreasonforthe one hour period preceding the powerinterrup tion. 6.3.4.3 The unit shall resume continuous oper ation within two hours ofrestoration ofpower and shall then operate continuouslyfor one half hour. Operation and resetting ofsafety devices priorto establishmentofcontinuous operationis permitted. 6.4 Low-Temperature Operation Test (Heating). Ground water-source heatpumps shall be designed and produced to pass the following low-temperature opera tion test when operating with initial air quantities as determined in 5.1.4.3. 5ARI STANDARD 325-85

6.4.1 Temperature Conditions. Air temperature entering and surrounding in door portion ofunit

.. 60 F [15.6°C) dry bulb Water temperature entering refrigerantto-water heat exchanger 45 F [7.2°C] Water flow rate Maintained at 90 percent offlow rate specified in low temperature heating 

### test of5.1.4.ld 6.4.2 Procedure. Thetest shall be continuous with the unit on the heating mode, fornotless thanfour hours afterestablishmentofthe specifiedtempera ture conditions. 6.4.3 Requirements. During the entire test, the heat pump shall operate without damage to the equipment. 6.5 

### Insulation Efficiency Test (Cooling) (Not required for heating-only units). Ground water-source heat pumps shall be designed and produced to pass the fol lowing insulation efficiency testwhen operating with air quantities as determined in 5.1.4.3 with controls, fans, dampers and grilles set to produce the maximum ten dency to sweat, provided such settings are not contrary to the manufacturer’s instructions to the user. 6.5.1 Temperature Conditions. Air temperature entering and surrounding in door portion ofunit

.. 80 F 

### [26.7°C] dry bulb, 75 F [23.9°C] wet bulb Water temperature entering refrigerantto-water heat exchanger 50 F [10°C] Waterflow rate Maintained same as in flow rate specified in low temperature cooling test of5.1.4.lb
6.5.2 Procedure. After establishment of the specified temperature conditions, the unit shall be operated continuously for a period offour hours. 6.5.3 Requirements. During the test, no con densed water shall drip, run or blow offfrom the unit casing.
6.6 Tolerances. The conditions for the tests outlined in 6.2, 6.3, 6.4 and 6.5 are average values subjectto toler
ances of ± 1.0 F 

### [±0.56°C] for airwet bulb and dry bulb temperatures, ±0.5 F [±0.28°C) forwatertemperatures and ±1.0 percent ofthe reading for voltages.

Section 7. Safety Recommendations 7.1 Refrigerating System. It is strongly recommended that the refrigerating system be designed, constructed, and assembled so as to be in accordance with the ANSI/ASHRAE 15-1978 Safety Code for Mechanical 

### Refrigeration (American Society ofHeating, Refrigera ting and Air-Conditioning Engineers, Inc.) 7.2 Product Safety. It is strongly recommended that ground water-source heat pumps for use with duct sys tems be designed, constructed and assembled so as to meet the safety requirements ofUL Standard for Heat Pumps (Underwriters’ Laboratories, Inc. Standard559, February 1983). It is strongly recommended that freedelivery ground water-source heat pumps be designed, constructed and assembled so as to meet the safety re quirements ofUL StandardforAir Conditioners, Room (Underwriters’ Laboratories, Inc. Standard 484, 1982).

Section 8. Voluntary Conformance 8.1 Conformance. Conformance with this standard shall notbe claimed orimplied forground water-source heat pumps coming within the scope of this standard unless the heat pumps for which such claims are made meet all the performance, safety and rating require ments specified herein. 

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