Carrier 38HDA Service Manual

Air Conditioners andHeat Pumps UsingR-22 RefrigerantApplication Guideand Service ManualNOTE: Read the entire instruction manual before starting theins

Example:3—230 or 208–230 or 208/230, 1 Phase, 60 Hertz5—230 or 208–230 or 208/230, 3 Phase, 60 Hertz6—460, 3 Phase, 60 Hertz7—220/240, 1 Phase, 50 Her

Step 3—Information Plate—WeatherMaker™The information plate is secured to the front of the control box andprovides a cover for it. (See Fig. 9.) This

ELECTRICALExercise extreme caution when working on any electricalcomponents. Shut off all power to system prior to trouble-shooting. Some troubleshoot

connection will be exposed to moisture, it is very important tocover the entire connection completely to prevent an electrochemi-cal action that will

Step 3—CapacitorsCapacitors can store electrical energy when power is off.Electrical shock can result if you touch the capacitor termi-nals and discha

5. Try restarting compressor without boost capacitor. If after 2attempts compressor does not start, remove thermistor. Add anaccessory start-capacitor

across them. Both PTC device and capacitor-relay start system arestandard equipment on some of these units. They are also availableas accessories and

heater. Carefully feel area around crankcase heater. If warm,crankcase heater is probably functioning. Do not rely on thismethod as absolute evidence

Step 7—Pressure SwitchesPressure switches are protective devices wired into control circuit(low voltage). They shut off compressor if abnormally high

have closed, energizing supplemental heat (W2) and reversingvalve solenoid (O).11. Unit should remain in defrost no longer than 10 minutes.Actual time

SAFETY CONSIDERATIONSService and repair of these units should be attempted only bytrained service technicians familiar with Carrier standard servicein

across defrost thermostat leads using ohmmeter. Resistance ofzero indicates defrost thermostat is closed and operatingproperly.9. Short between the sp

12. After a few minutes in defrost (cooling) operation, liquid lineshould be warm enough to have caused defrost-thermostatcontacts to open. Check resi

This control has the option of shutting down the compressor for 30seconds while going into and out of defrost modes. This isaccomplished by turning DI

For suspected electrical failures, check for loose or faulty electricalconnections or defective fan-motor capacitor. Fan motor isequipped with thermal

If service alarm needs replacing, shut off all power to unitbefore attempting removal. Electrical shock can cause per-sonal injury or death.Troublesho

Y—Energizes contactor for first-stage cooling or first-stage heat-ing for heat pumps (yel).O—Energizes reversing valve on heat pumps (orn).C—Common si

NOISY COMPRESSORNoise may be caused by a variety of internal problems such asloosened hardware, broken mounting springs, etc. System prob-lems such as

To determine if any winding has a break in the internal wires andcurrent is unable to pass through:1. Be sure all power is off.2. Discharge all capaci

acids, contaminate system. If burnout is severe enough, systemmust be cleaned before replacement compressor is installed. The 2types of motor burnout

Step 4—Discharge Solenoid ValveSome larger units equipped with scroll compressors contain asolenoid valve that is piped between the discharge tube and

Step 9—Wind BaffleA field-fabricated sheet-metal cover used to stop prevailing windsor where outdoor ambient temperature is less than 55°F during unit

Fig. 31—CES0130075 3–Phase Monitor BoardA00010Fig. 32—CESO130075 3–Phase Monitor Wiring DiagramA00011EQUIPGNDCONTL1COMP1121T1T2T3*CHL2L31323OFMCAPCONT

with an isolated compressor compartment, greatly reduces theoverall sound level of the unit. The unit utilizes front and backseating valves. The heat-

occur. When high-speed, heat-pump heating is required, thecontrol provides a Y2 (24vac) signal back to the thermostat toenergize high-speed-indicator

DEFROSTThe 2-speed control logic for the defrost function is the standardtime and temperature initiated, time or temperature terminated.Defrost occurs

balance-point POT. (See Fig. 36.) Temperatures that may beselected are 10°,15°,20°,25°,30°,35°,40°, and 45°F. The POTis factory-set at 45°F.LOW-SPEED

The 2-speed compressor contains motor windings that providelow-speed, 4–pole (1750 rpm) and high-speed, 2–pole (3500 rpm)operation. Refer to Fig. 40 t

then off, the signal will remain off for 4 sec before turning on againto start the next cycle. The PWM is called a 20–percent duty-cyclesignal. If the

Fig. 42—Low-Speed WindingsA91446EQUIPGNDSC17 27EXTMAIN11 21C1L1BRCAPHLOWSTARTMAINT2T7COMPT1HIGHSTARTT3T8251HSSR2515C22616C22212C12313C1CFC21424C2L2LSS

CONTROL-BOARD POWER INPUTS AND OUTPUTSSee Fig. 35 and 39 for inputs and outputs.BLEED RESISTORThe bleed resistor is a 150k, 2–watt resistor across the

This discussion assumes that system is pressurized with either allrefrigerant or a mixture of nitrogen and refrigerant.If system has been operating fo

Calculate the linear length of vapor tube required, adding anylosses for the total number of elbows for application. (See Table6.) Using this equivale

pressurized. To pressurize the service port, this valve must bemoved off the back-seating position. This valve does not contain aSchrader fitting. Bot

WEATHERMAKER™ PRODUCTS EXCEPT 1992 PRODUC-TION1. Shut off power to unit.2. Pump unit down using pumpdown procedure described in thisservice manual.3.

4. Braze new valve onto used stubs. Keep stubs oriented cor-rectly. Scratch corresponding matching marks on old valveand stubs and on new valve body t

Step 8—Thermostatic-Expansion Valve (Bi-Flow TXV)The standard TXV is a metering device that is used in condensingand heat-pump systems to adjust to ch

Fig. 51—TXV in Cooling ModeA88406OUTLETINLETPUSHRODSBYPASS TXVDIAPHRAGMNEEDLE VALVESPRINGCHECK VALVE(CLOSED)BYPASS TUBEDISTRIBUTORFEEDER TUBESCAPILLAR

NOTE: Coil may be removed for access to accumulator. Refer toappropriate sections of service manual for instructions.Wear safety glasses and gloves wh

7. Locate superheat temperature located in previous step andvapor pressure in Table 23. At this intersection note vapor-linetemperature.8. If unit has

Table 23—Required Vapor Temperature (°F)SUPERHEAT TEMP(°F)VAPOR PRESSURE AT SERVICE PORT (PSIG)61.5 64.2 67.1 70.0 73.0 76.0 79.2 82.4 85.70 35 37 39

5. Restore power to unit.CLEANING OUTDOOR FAN MOTOR AND BLADE1. Remove fan motor and blade. Refer to Remove Fan-MotorAssembly section of this manual.

2. Check to be sure caps are installed on service valves and thatthey are tight.3. Check to be sure tools, loose parts, and debris are removedfrom the

Step 3—Metering Device SizingThe metering device for a long-line application must be flexibleenough to compensate for frictional losses due to long re

Fig. 54—Air-Conditioner Troubleshooting ChartA90208AIR CONDITIONERTROUBLESHOOTING CHARTNO COOLING ORINSUFFICIENTCOOLINGCOMPRESSORWILL NOT RUNCONTACTOR

Fig. 55—Heat-Pump Troubleshooting Chart — Cooling CycleA90207HEAT PUMPTROUBLESHOOTING–COOLING CYCLENO COOLING ORINSUFFICIENTCOOLINGCOMPRESSORWILL NOT

Fig. 56—Heat-Pump Troubleshooting Chart — Heating CycleA90206HEAT PUMPTROUBLESHOOTING–HEATING CYCLENO HEATING ORINSUFFICIENTHEATINGCOMPRESSORWILL NOT

Each type of solenoid has an indicator flow arrow stamped on thevalve body. When solenoid is closed (not energized) and pressureis applied in directio

Step 6—2–Speed ApplicationsOutdoor units may be connected to indoor section using accessorytubing package or field-supplied refrigerant grade tubing o

Fig. 3—Tube Bend LossesTable 6—Fitting Losses in Equivalent FtTUBE SIZE OD(IN.)REFERENCE DIAGRAM IN FIG. 1ABC5/8 1.6 1.0 0.83/4 1.8 1.2 0.97/8 2.0 1.4

UNIT IDENTIFICATIONStep 1—Product Number Stamped on Unit-Rating PlateThe unit product number has 16 positions containing groups ofnumbers and letters