Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations. Catalog No. 02-38QR0001-SI Printed in U.S.A. Form 38QR-3SI Pg 1 1-06 Replaces: 38QRC-1SI Book 1 4 Tab 3e 2f Installation, Start-Up and Service Instructions CONTENTS Page SAFETY CONSIDERATIONS ...................... 1 INSTALLATION ................................ 1-10 Step 1 — Complete Pre-Installation Checks ...... 1 • UNPACK UNIT • INSPECT SHIPMENT • CONSIDER SYSTEM REQUIREMENTS • MATCHING THE HEATPUMP UNIT TO AN INDOOR UNIT • CHECK ACCURATER METERING DEVICE Step 2 — Rig and Mount Unit ..................... 4 • MOUNTING ON GROUND • MOUNTING ON ROOF • RIGGING Step 3 — Complete Refrigerant Piping Connections ................................... 5 • FILTER DRIER • MAKE PIPING SWEAT CONNECTORS • PROVIDE SAFETY RELIEF Step 4 — Make Electrical Connections ........... 5 • POWER WIRING • CONTROL CIRCUIT WIRING START-UP ....................................... 10 SERVICE ..................................... 11-14 MAINTENANCE ................................. 14 TROUBLESHOOTING......................... 14-16 SAFETY CONSIDERATIONS Installing and servicing air conditioning equipment can be hazardous due to system pressure and electrical components. Only trained and qualified service personnel should install or service air conditioning equipment. Untrained personnel can perform basic maintenance, such as cleaning and replacing filters. All other operations should be performed by trained service personnel. When working on air conditioning equipment, observe safety precautions in litera- ture, tags, and labels attached to unit. Follow all safety codes. Wear safety glasses and work gloves. Use quenching cloth for brazing operations. Have fire extinguisher available. Read these instructions thoroughly . Consult local building codes and the National Electrical Code (NEC) for special installation requirements. INSTALLATION Step 1 — Complete Pre-Installation Checks UNPACK UNIT (See Fig. 1) — Move the unit to final loca- tion. Remove carton from unit, being careful not to damage service valves and grilles. INSPECT SHIPMENT — File a claim with the shipping company if shipment is damaged or incomplete. CONSIDER SYSTEM REQUIREMENTS — Consult local building codes and the NEC for special installation requirements. Allow sufficient space for airflow clearance, wiring, refrig- erant piping, and servicing unit. See Fig. 2 and Tables 1-4. Locate unit so that condenser airflow is unrestricted on both sides. Refer to Fig. 2 and Tables 1-4. Unit may be mounted on a level pad directly on base legs or mounted on raised pads at support points. See Fig. 2 for center of gravity. MATCHING THE HEAT PUMP UNIT TO AN INDOOR UNIT — The 38QRF,QRR units can be matched to a corre- sponding indoor unit. The 38QRF018-030 units can be matched with an in-ceiling cassette or high wall indoor unit. The 38QRF035 unit can only be matched with in-ceiling cassette indoor units. The 38QRF036 unit can only be matched with high wall indoor units. Refer to separate indoor unit literature for more information. Before installing or servicing system, always turn off main power to system. There may be more than one disconnect switch. Turn off accessory heater power if applicable. Elec- trical shock can cause serious personal injury or death. Puron® (R-410A) refrigerant systems operate at higher pressures than standard R-22 systems. Do not use R-22 ser- vice equipment or components on Puron refrigerant equip- ment. If service equipment is not rated for Puron refrigerant, equipment damage or personal injury may result. 38QRF018-036 Duct Free Heat Pumps 38QRR018-060 Ducted Heat Pumps Fig. 1 — 38QRF,QRR Units
16
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Transcript
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.Catalog No. 02-38QR0001-SI Printed in U.S.A. Form 38QR-3SI Pg 1 1-06 Replaces: 38QRC-1SIBook 1 4
Installing and servicing air conditioning equipment can behazardous due to system pressure and electrical components.Only trained and qualified service personnel should install orservice air conditioning equipment.
Untrained personnel can perform basic maintenance, suchas cleaning and replacing filters. All other operations should beperformed by trained service personnel. When working on airconditioning equipment, observe safety precautions in litera-ture, tags, and labels attached to unit.
Follow all safety codes. Wear safety glasses and workgloves. Use quenching cloth for brazing operations. Have fireextinguisher available. Read these instructions thoroughly.Consult local building codes and the National Electrical Code(NEC) for special installation requirements.
INSTALLATION
Step 1 — Complete Pre-Installation ChecksUNPACK UNIT (See Fig. 1) — Move the unit to final loca-tion. Remove carton from unit, being careful not to damageservice valves and grilles.
INSPECT SHIPMENT — File a claim with the shippingcompany if shipment is damaged or incomplete.CONSIDER SYSTEM REQUIREMENTS — Consult localbuilding codes and the NEC for special installationrequirements.
Allow sufficient space for airflow clearance, wiring, refrig-erant piping, and servicing unit. See Fig. 2 and Tables 1-4.
Locate unit so that condenser airflow is unrestricted on bothsides. Refer to Fig. 2 and Tables 1-4.
Unit may be mounted on a level pad directly on base legs ormounted on raised pads at support points. See Fig. 2 for centerof gravity.MATCHING THE HEAT PUMP UNIT TO AN INDOORUNIT — The 38QRF,QRR units can be matched to a corre-sponding indoor unit. The 38QRF018-030 units can bematched with an in-ceiling cassette or high wall indoor unit.The 38QRF035 unit can only be matched with in-ceilingcassette indoor units. The 38QRF036 unit can only be matchedwith high wall indoor units. Refer to separate indoor unitliterature for more information.
Before installing or servicing system, always turn off mainpower to system. There may be more than one disconnectswitch. Turn off accessory heater power if applicable. Elec-trical shock can cause serious personal injury or death.
Puron® (R-410A) refrigerant systems operate at higherpressures than standard R-22 systems. Do not use R-22 ser-vice equipment or components on Puron refrigerant equip-ment. If service equipment is not rated for Puron refrigerant,equipment damage or personal injury may result.
CHECK ACCURATER METERING DEVICE — The cor-rect AccuRater (bypass type) refrigerant control is required forsystem capacity optimization. An AccuRater device withfield-replaceable piston (see Fig. 3) is supplied with theoutdoor unit. Refer to the AccuRater metering device table inseparate indoor unit installation instructions to determine thecorrect AccuRater piston size required for the condenser/evaporator system being installed.
Piston style as shown in Fig. 3 is shipped with the unit. Donot interchange components between the AccuRater devicetypes. Matching of outdoor unit with indoor unit may requirefield replacement of piston. Replace piston, if required, beforeconnecting refrigerant lines. See Fig. 3. Piston replacementinstructions are included in the indoor unit installation instruc-tions. After system installation is complete, see the RefrigerantCharging section on page 13 to check and/or adjust refrigerantcharge.
Step 2 — Rig and Mount UnitMOUNTING ON GROUND — Mount unit on a solid, levelconcrete pad. Position unit so water or ice from roof does notfall directly onto unit. Use field-provided snow stand or icerack where prolonged subfreezing temperatures or heavy snowoccurs. If conditions or local codes require unit be fastened to apad, 6 field-supplied tiedown bolts should be used and fastenedthrough slots provided in unit mounting feet.MOUNTING ON ROOF — Mount unit on a level platformor frame at least 6 in. above roof surface. Isolate unit and tub-ing from structure.
38QRR UNIT SIZE 018 024 030 036 048 060OPERATING WEIGHT (lb) 167 176 187 232 278 306REFRIGERANT R-410ACOMPRESSOR TYPE Scroll
Keep the unit upright and lift unit using a sling. Use card-board or padding under the sling, and spreader bars to preventsling damage to the unit. See Fig. 4. See Fig. 2 for center ofgravity reference. Install the unit so that the coil does not faceinto prevailing winds. If this is not possible and constant windsabove 25 mph are expected, use accessory wind baffle. Seeinstallation instructions provided with the accessory kit.NOTE: Accessory wind baffles should be used on all unitswith accessory low ambient temperature control.
Field-fabricated snow or ice stands may be used to raise unitwhen operation will be required during winter months. Unitsmay also be wall mounted using the accessory wall-mountingkit.
Step 3 — Complete Refrigerant Piping Con-nections — Outdoor units may be connected to indoorunits using field-supplied tubing of refrigerant grade and condi-tion. See Tables 3 and 4 for correct line sizes. Do not use lessthan 10 ft of interconnecting tubing.
When more than 50 ft of interconnecting tubing and morethan 30 ft of vertical lift is used, consult the residential long lineapplication instruction guide.
If either refrigerant tubing or indoor coil is exposed tothe atmosphere, the system must be evacuated following goodrefrigeration practices.
Run refrigerant tubes as directly as possible, avoidingunnecessary turns and bends. Suspend refrigerant tubes so theydo not damage insulation on vapor tube and do not transmit
vibration to structure. Also, when passing refrigerant tubesthrough a wall, seal the opening so that vibration is not trans-mitted to structure. Leave some slack in refrigerant tubes be-tween structure and outdoor unit to absorb vibration. Refer toseparate indoor unit installation instructions for additionalinformation.FILTER DRIER — The filter drier must be replaced whenev-er the refrigeration system is exposed to the atmosphere. SeeFig. 3 for filter drier installation.
Only use factory specified liquid-line filter driers with ratedworking pressures less than 600 psig.NOTE: Do not install a suction-line filter drier in liquid line.MAKE PIPING SWEAT CONNECTIONS — Remove plas-tic caps from liquid and suction service valves. Use refrigerantgrade tubing. Service valves are closed from the factory and areready for brazing. After wrapping the service valve with a wetcloth, the tubing set can be brazed to the service valve usingeither silver bearing or non-silver bearing brazing material.Consult local code requirements. Refrigerant tubing and theindoor coil are now ready for leak testing.NOTE: Unit is shipped with R-410A factory charge indicatedon nameplate.
Pass nitrogen or other inert gas through piping while braz-ing to prevent formation of copper oxide.
PROVIDE SAFETY RELIEF — A fusible plug is located inunit suction line; do not cap this plug. If local code requiresadditional safety devices, install as directed.
Step 4 — Make Electrical Connections
Be sure unit panels are securely in place prior to rigging.Loose unit panels could result in equipment damage or per-sonal injury.
DO NOT BURY MORE THAN 36 IN. OF REFRIGER-ANT PIPE IN THE GROUND. If any section of pipe isburied, there must be a 6-in. vertical rise to the valveconnections on the outdoor unit. If more than therecommended length is buried refrigerant may migrate tocooler, buried section during extended periods of systemshutdown. This causes refrigerant slugging and couldpossibly damage the compressor at start-up.
To avoid damage while brazing, service valves should bewrapped with a heat-sinking material such as a wet cloth.
When brazing tubing sets to the service valves, a brazingshield MUST be used to prevent damage to the painted unitsurface.
Unit cabinet must have an uninterrupted, unbroken electri-cal ground to minimize the possibility of personal injury ifan electrical fault should occur. This ground may consist ofelectrical wire connected to unit ground lug in control com-partment, or conduit approved for electrical ground wheninstalled in accordance with NEC and local electricalcodes. Failure to follow this warning could result in theinstaller being liable for the personal injury of others.
Unit failure as a result of operation on improper linevoltage or excessive phase imbalance constitutes abuse andmay cause damage to electrical components. Such opera-tion would invalidate any applicable Carrier warranty.
Before performing service or maintenance, be sure indoorunit main power switch is turned OFF and indoor blowerhas stopped. Failure to do so may result in electrical shockor injury from rotating fan blades.
Fig. 4 — Lifting Unit With Sling
6
POWER WIRING — Unit is factory wired for voltage shownon nameplate. Provide adequate, fused disconnect switchwithin sight from unit, readily accessible, but out of reach ofchildren. Provision for locking the switch open (off) is advis-able to prevent power from being turned on while unit is beingserviced. Disconnect switch, fuses, and field wiring mustcomply with the NEC and local code requirements. Use copperwire only between the disconnect switch and unit. Useminimum 60 C wire for the field power connection.
Route power wires through the opening in unit side paneland connect in the unit control box as shown on the unit labeldiagram and Fig. 5. Unit must be grounded.CONTROL CIRCUIT WIRING — Control voltage is 24 v(40 va minimum). See Fig. 6-8 for field-supplied wiringdetails. Route control wire through opening in unit side panelto connection in unit control box.NOTE: For wire runs up to 50 ft, use no. 18 AWG (AmericanWire Gage) insulated wire. For 50 to 75 ft, use no. 16 AWGinsulated wire. For over 75 ft, use 14 AWG insulated wire.NOTE: All wiring must conform to NEC and local codes.NOTE: Operating unit on improper line voltage constitutesabuse and could affect Carrier warranty. See Tables 5A and5B. Do not install unit in a system where voltage may fluctuateabove or below permissible limits.
See Tables 5A and 5B for recommended fuse sizes. Whenmaking electrical connections, provide clearance at the unit forrefrigerant piping connections.NOTE: The 38QRF units are supplied with a 24-v controltransformer. The 38QRR units use the control transformer sup-plied with the matched indoor unit.
LEGEND
Fig. 5 — Line Power Connections
NEC — National Electrical CodeTB — Terminal Board
TB ConnectionsField WiringFactory Wiring
— —
38QRF UNITS 38QRR UNITS
NOTE: For more information see schematic inside unit. For additional unit combinations, see installation guide.
Fig. 6 — Typical Control Circuit Connections
7
38Q
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MAT
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9
Table 5A — 38QRF Electrical Data
LEGEND
*Permissible limits of the voltage range at which unit will operatesatisfactorily.
NOTES:1. Control circuit is 24 v on all units and requires an external power
source.2. All motors and compressors contain internal overload protection.3. In compliance with NEC (U.S.A. Standard) requirements for mul-
timotor and combination load equipment (refer to NEC Articles430 and 440), the overcurrent protective device for the unit shallbe fuse or HACR breaker.
4. Motor RLA values are established in accordance with UL (Under-writers’ Laboratories) Standard 465 (U.S.A. Standard).
5. Unbalanced 3-Phase Supply VoltageNever operate a motor where a phase imbalance in supply volt-age is greater than 2%. Use the following formula to determinethe percentage of voltage imbalance:
EXAMPLE: Supply voltage is 460-3-60.AB = 452 vBC = 464 vAC = 455 v
Determine maximum deviation from average voltage:(AB) 457 – 452 = 5 v(BC) 464 – 457 = 7 v(AC) 457 – 455 = 2 v
Maximum deviation is 7 v.
Determine percentage of voltage imbalance:
This amount of phase imbalance is satisfactory as it is below themaximum allowable of 2%.
38QRFUNIT SIZE V-PH-Hz
VOLTAGERANGE*
COMPRESSOR OUTDOOR FAN MOTORMIN CKT
AMPSFUSE/HACRBKR AMPSRLA LRA FLA NEC Hp kW OutMin Max
CSA — Canadian Standards AssociationFLA — Full Load AmpsHACR — Heating, Air Conditioning, RefrigerationLRA — Locked Rotor AmpsMCA — Minimum Circuit Amps per NEC Section 430-24NEC — National Electrical CodeRLA — Rated Load Amps (Compressor)
= 100 xmax voltage deviation from average voltage
average voltage
Average Voltage =452 + 464 + 455
3
=1371
3= 457
% Voltage Imbalance = 100 x7
457= 1.53%
IMPORTANT: Contact your local electric utility company imme-diately if the supply voltage phase imbalance is more than 2%.
10
Table 5B — 38QRR Electrical Data
LEGEND
*Permissible limits of the voltage range at which unit will operatesatisfactorily.
NOTES:1. Control circuit is 24 v on all units and requires an external power
source.2. All motors and compressors contain internal overload protection.3. In compliance with NEC (U.S.A. Standard) requirements for mul-
timotor and combination load equipment (refer to NEC Articles430 and 440), the overcurrent protective device for the unit shallbe fuse or HACR breaker.
4. Motor RLA values are established in accordance with UL (Under-writers’ Laboratories) Standard 465 (U.S.A. Standard).
5. Unbalanced 3-Phase Supply VoltageNever operate a motor where a phase imbalance in supply volt-age is greater than 2%. Use the following formula to determinethe percentage of voltage imbalance:
EXAMPLE: Supply voltage is 460-3-60.AB = 452 vBC = 464 vAC = 455 v
Determine maximum deviation from average voltage:(AB) 457 – 452 = 5 v(BC) 464 – 457 = 7 v(AC) 457 – 455 = 2 v
Maximum deviation is 7 v.
Determine percentage of voltage imbalance:
This amount of phase imbalance is satisfactory as it is below themaximum allowable of 2%.
START-UPPreliminary Checks
1. Check that all internal wiring connections are tight andthat all barriers, covers, and panels are in place.
2. Field electrical power source must agree with unit name-plate rating.
3. All service valves must be open.4. Belly-band crankcase heater must be tight on compressor
crankcase for those units with belly-band heaters.
Leak Test — Field piping and fan coil must be leak testedby pressure method. Use R-410A at approximately 25 psigbacked up with an inert gas to a total pressure not to exceed245 psig.NOTE: Leak detectors should be designed to detect HFC(hydrofluorocarbon) refrigerant.
Evacuate and Dehydrate — Field piping and fan coilmust be evacuated and dehydrated.
Charge System — Release factory charge into systemby opening (backseating) liquid and suction line service valves.Add charge amount as required for the total system. Refer toseparate indoor unit installation instructions for the requiredtotal system charge when connected by 25 ft of tubing.
To Start Unit — Be sure that the field disconnect isclosed. Set room thermostat below ambient temperature. Oper-ate unit for 15 minutes, then check system refrigerant charge.See the Refrigerant Charging section on page 13.
When ambient temperature will fall below 55 F, accessorylow-ambient controller (part no. 53DS900086) is required.
38QRRUNIT SIZE V-PH-Hz
VOLTAGERANGE*
COMPRESSOR OUTDOOR FAN MOTORMIN CKT
AMPSFUSE/HACRBKR AMPSRLA LRA FLA NEC Hp kw OutMin Max
CSA — Canadian Standards AssociationFLA — Full Load AmpsHACR — Heating, Air Conditioning, RefrigerationLRA — Locked Rotor AmpsMCA — Minimum Circuit Amps per NEC Section 430-24NEC — National Electrical CodeRLA — Rated Load Amps (Compressor)
= 100 xmax voltage deviation from average voltage
average voltage
Average Voltage =452 + 464 + 455
3
=1371
3= 457
% Voltage Imbalance = 100 x7
457= 1.53%
IMPORTANT: Contact your local electric utility company imme-diately if the supply voltage phase imbalance is more than 2%.
11
SERVICE
Outdoor Fan — A reinforced wire mount holds the out-door fan assembly in position. See Fig. 9 for proper mountingposition.
High-Pressure Relief Valve — The high-pressure re-lief valve is located in the compressor. The relief valve opens ata pressure differential of approximately 550 to 625 ± 50 psidbetween suction (low side) and discharge (high side) to allowpressure equalization.
Internal Current and Temperature SensitiveOverload — The control resets automatically wheninternal compressor motor temperature drops to a safe level(overloads may require up to 45 minutes to reset). When aninternal overload is suspected of being open, check by using anohmmeter or continuity tester.
Pumpdown Procedure — The system may be pumpeddown in order to make repairs on the low side without losingcomplete refrigerant charge.
NOTE: When system must be opened for service, recoverrefrigerant, break vacuum with dry nitrogen before openingsystem.
1. Attach pressure gage to suction service valve gage port.2. Frontseat the liquid line valve.
3. Start unit and run until suction pressure reaches 20 psig.4. Shut unit off and frontseat suction valve.
5. Depressurize low side of unit and recover refrigerantfollowing accepted practices.
High-Pressure Switch — The high-pressure switch,located on discharge line, protects against high dischargepressures caused by such events as overcharge, condenser-fanmotor failure, system restriction, etc. It opens on pressure rise atabout 650 ± 10 psig. If system pressures go above this settingduring abnormal conditions, the switch opens.
The high-pressure switch is checked with an ohmmeter. Ifsystem pressure is below 650 psig switch shows continuity.
Crankcase Heater — The crankcase heater preventsrefrigerant migration and compressor oil dilution duringshutdown when compressor is not operating. If the crankcaseheater is deenergized for more than 6 hours, both compressorservice valves must be closed.
The crankcase heater is powered by the high-voltage powerof the unit. It is connected across the line side of the contactorand operates continuously.
To troubleshoot:1. Apply voltmeter across crankcase heater leads to see if
heater voltage is on. Do not touch heater. Carefully feelarea around crankcase heater; if warm, crankcase heateris functioning.
2. With power off and heater leads disconnected, checkacross leads with ohmmeter. Do not look for a specificresistance reading. Check for resistance or an open cir-cuit, and change heater if an open circuit is detected.
Service Valves — The service valves in the outdoor unitcome from the factory frontseated. This means the refrigerantcharge is isolated from the line-set connection ports. To preventdamage to the valve, use a wet cloth or other accepted heat sinkmaterial on the valve before brazing.
The service valve cannot be field repaired, therefore, only acomplete valve or valve stem seal and service port caps areavailable for replacement.
Defrost Control38QRR UNITS — The control, which consists of defrost con-trol board and defrost thermostat, interrupts the normal systemheating operation to defrost the outdoor coil, if the coil saturat-ed suction temperature indicates freezing temperatures. Defrostcontrol board can be field set to check need for defrost every30, 50, or 90 minutes of operating time, by connecting thejumper (labeled W1, on the circuit board) to the spade terminalfor the defrost time desired. The board is factory set for90 minutes. The defrost period is field selectable, dependingupon geographic areas and defrost demands. Control board hasadditional feature that allows unit to restart in defrost cycle ifroom thermostat is satisfied during defrost. Defrost controlsimultaneously tops outdoor fan, energizes reversing valvesolenoid to return system to cooling cycle (outdoor unit ascondenser, indoor unit as evaporator), and activates accessoryelectric heater. The defrost timer limits defrosting period to10 minutes. Normally, the frost is removed and the defrostthermostat contacts open to terminate defrosting before10 minutes have elapsed.
Before performing recommended maintenance, be sureunit main power switch is turned off. Failure to do so mayresult in electrical shock or injury form rotating fan blade.
Never open system to atmosphere while it is under avacuum. Equipment damage may result.
The unit coils hold only the factory-designated amount ofrefrigerant. Additional refrigerant may cause units torelieve pressure through the compressor internal pressurerelief valve (indicated by a sudden rise of suction pressure)before suction pressure reaches 20 psig. If this occurs, shutoff unit immediately then frontseat the suction valve andremove and recover excess refrigerant following acceptedpractices. Equipment damage may result.
DO NOT attempt to simulate these system abnormalities— high pressures pose a serious safety hazard.
Use extreme caution when troubleshooting this device, asline voltage is continually present. Serious personal injurycould result.
Fig. 9 — Outdoor Fan Mounting Positions
UNIT SIZE in. (mm)38QRF,QRR018,024 38QRF,QRR030-036 38QRR048,060
0.433 (11) 0 0
12
When defrosting is terminated, the outdoor-fan motor is en-ergized, and reversing valve solenoid is deenergized, returningunit to heating cycle.38QRF UNITS — The 38QRF defrost function is controlledby the matched indoor unit. The defrost cycle time is controlledby the system control circuitry and cannot be field modified.The defrost cycle is initiated by the defrost thermostat switchlocated on the outdoor coil. At the start of the Defrost cycle theelectric heaters (if installed), compressor and outdoor fan willturn off. After 40 seconds the reversing valve will set to thecooling state. After another 6 seconds the compressor willrestart.
When the Defrost cycle ends, the compressor and indoorfan will remain off for the first 40 seconds. The reversing valvewill set to the heating state. After another 6 seconds the systemwill return to normal operation.
Reversing Valve — In heat pumps, changeover betweenheating and cooling modes is accomplished with a valve thatreverses flow of refrigerant in the system. The reversing valvesolenoid can be checked with the power off using an ohmme-ter. Check for continuity and shorting to ground. With controlcircuit (24 v) power on, check for correct voltage at solenoidcoil, and for burned or overheated solenoid.
With unit operating, other items can be checked, such asfrost or condensate on refrigerant lines.
Using a remote measuring device, check inlet and outlet linetemperatures. Do not touch lines. If reversing valve is operat-ing normally, inlet and outlet temperatures on appropriate linesshould be similar. Any temperature difference would be due toheat loss or gain across valve body. Temperatures are bestchecked with a remote reading electronic-type thermometerwith multiple probes.
Figures 10 and 11 show test points on reversing valve forrecording temperatures. Insulate points for more accuratereading. If valve is defective:
1. Shut off all power to unit.2. Remove all charge from system.3. Remove valve using a tubing cutter.4. Install new valve (wrap valve with a wet rag to prevent
overheating while brazing).5. After valve is brazed in, check for leaks.6. Evacuate and charge system. Operate system in both
modes several times to be sure valve functions properly.
Subcooling Method — For 38QRR units only, the sub-cooling method is used to check and adjust charge during thecooling season. Refer to Table 6 and the following procedure:NOTE: For use with residential fan coils and the 40QA060under ceiling unit only.
1. Operate unit a minimum of 15 minutes before checkingcharge.
2. Measure liquid line temperature near liquid line servicevalve, and measure the liquid pressure at the liquid lineservice valve. Use a digital thermometer for all tempera-ture measurements. DO NOT use mercury or dial-typethermometers.
3. Refer to Table 6. Find the temperature point at which therequired subcooling temperature intersects the measuredliquid line pressure.
4. If the measured liquid line temperature does not agreewith the required liquid line temperature, ADD refriger-ant to lower the temperature, or REMOVE refrigerant toraise the temperature (allow a tolerance of ± 3° F).
Compressor Lockout Switch — The 38QRR unitsare provided with a compressor lockout protective device. Ifthe compressor shuts down due to any safety device, a currentloop monitoring the compressor current senses no current flow.The unit will lock out until the control power is interrupted toreset the lockout. Determine the reason for the safety trip. Torestart, turn the thermostat to the OFF position and then set thethermostat to an operating position.
All units are shipped with the refrigerant charge listed onnameplate. See indoor unit Installation Instructions for addi-tional charge requirements.NOTE: Do not vent or depressurize unit refrigerant to atmo-sphere. Remove and recover refrigerant following acceptedpractices.NOTE: For 38QRF units only, charge to the nameplate. Seethe indoor unit owner’s manual for any additional chargerequirements.
Consider the following when working with Puron® refrig-erant (see Table 7):• Puron refrigerant cylinders are rose colored.• Recovery cylinder service pressure rating must be
400 psig, DOT (Department of Transportation) 4BA400or DOT BW400.
• Puron systems should be charged with liquid refrigerant.Use a commercial type metering device in the manifoldhose when charging into suction line with compressoroperating.
• Manifold sets should be 700 psig high side and 180 psiglow side with 550 psig low-side retard.
• Use hoses with 700 psig service pressure rating.• Puron refrigerant, as with other HFCs, is only compatible
with POE oils.• Vacuum pumps will not remove moisture from oil.• Polyol Ester oils absorb moisture rapidly. Do not expose
oil to atmosphere.• Polyol Ester oils may cause damage to certain plastics
and roofing materials.• Wrap all filter driers and service valves with wet cloth
when brazing.• A factory approved, liquid-line filter drier is required on
every unit.• Do not use a TXV (thermostatic expansion valve)
designed for use with R-22 refrigerant. Refer to separateindoor installation instructions for more details.
• If using a suction line drier, do not leave in place formore than 72 hours.
To prevent personal injury, wear safety glasses and gloveswhen handling refrigerant. Do not overcharge system —this can cause compressor flooding.
14
Table 7 — Pressure vs. Temperature Chart — Puron® Refrigerant (R-410A)
MAINTENANCE
LubricationCOMPRESSOR — Compressor contains factory oil charge;replace oil when lost. See Tables 3 and 4 for oil recharge. UseMobile 3MA-POE oil.
Cleaning Coils — Coil should be washed out with wateror blown out with compressor air. Note that the blow-thrudesign causes dirt and debris to build up on the inside of thecoils.
Clean coil annually or as required by location and outdoorair conditions. Inspect coil monthly and clean as required. Finsare not continuous through coil sections. Dirt and debris maypass through first section, become trapped between the row offins and restrict condenser airflow. Use a flashlight to deter-mine if dirt or debris has collected between coil sections. Cleancoil as follows:
1. Turn off unit power.2. Using a garden hose or other suitable equipment, flush
coil from the outside to remove dirt. Be sure to flush alldirt and debris from drain holes in base of unit. Fanmotors are waterproof.
TROUBLESHOOTING
See Fig. 12 and 13 for troubleshooting information.
Before performing recommended maintenance, be sureunit main power switch is turned off. Failure to do so mayresult in electric shock or injury from rotating fan blade.
15
LEGEND
NOTE: For systems with indoor units equipped with microprocessorcontrol, see separate controls, service, and troubleshooting manual.
Fig. 12 — Troubleshooting — Heating Cycle
NC — Normally ClosedODT — Outdoor Thermostat
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.Catalog No. 02-38QR0001-SI Printed in U.S.A. Form 38QR-3SI Pg 16 2-06A 1-06 Replaces: 38QRC-1SIBook 1 4
Tab 3e 2f
Copyright 2006 Carrier Corporation
LEGEND
NOTE: For systems with indoor units equipped with microprocessorcontrol, see separate controls, service, and troubleshooting manual.