Carrier GR-45 Operation And Service

Contents

Carrier GR-45 Operation And Service Manual pdf 42 page image

T-2954-94.16.2 Inspection And Cleaninga. At regular maintenance periods, remove brush cov-ers, examine and clean motor interior.b. Place main battery disconnect switch in OFF positionand lock.c. Remove all foreign material. such as dirt and carbondust with dry moderately compressed air. Clean bysuction if possible to avoid blowing foreign matterinto the motor.d. Confirm free movement of brushes to prevent bind-ing.e. Examine brush wear and general condition. If bro-ken, cracked chipped or worn to 1/3 the originallength, replace. Refer to paragraph 4.16.3.f. Examine the condition of the brush springs. A discol-ored spring is a sign of overheating which may weak-en the spring. If discolored, replace.g. Observe condition of communtator and armaturecoils4.16.3 Brush Replacementa. Place main battery disconnect switch in OFF positionand lock.b. Remove condenser motor, refer to paragraph 4.16.1.c. Remove brush covers, remove and inspect brush as-semblies. Replace if required.d. Replace brush covers and reinstall condenser motor.e. To reassemble, reverse the above procedure. Ensuremotor is properly seated in support.f. Verify the proper operation of motor.MOUNTINGCLIPFigure 4-12. Evaporator Fan Removal4.17 REPLACING EVAPORATOR FANa. Place main battery disconnect switch in OFF positionand lock.b. Disconnect wire leads to the motor. Mark leads forproper reassembly.c. Remove motor by lifting the mounting clip (seeFigure 4-12) up and out. Slide motor from unit.d. To reassemble, reverse procedure.4.18 REPLACING RETURN AIR FILTERSThe return air filters are located behind the return airgrill, inside the vehicle.The filters should be checked for cleanlinessperiodically depending on operating conditions. A dirtyfilter will restrict air flow over the evaporator coil whichmay cause insufficient cooling or heating and possiblefrost buildup on the coil. To remove the filters, do thefollowing.a. Place main battery disconnect switch in OFF positionand lock.b. Remove the return air grille.c. Loosen filter retaining clips and remove the filterfrom the grille.d. Reverse procedure to install new filters.4.19 THERMOSTATIC EXPANSION VALVEThe thermostat expansion valve (Figure 4-13) is anautomatic device which maintains constant superheat ofthe refrigerant gas leaving the evaporator regardless ofsuction pressure. The valve functions are: (a) automaticcontrol of refrigerant flow to match the evaporator loadand (b) prevention of liquid refrigerant entering thecompressor. Unless the valve is defective, it seldomrequires any maintenance.71 2345641. Power HeadAssembly2. Equalizer Connection3. Bulb4. Gasket5. Cage Assembly6. Body Flange7. Cap screwFigure 4-13. Thermostatic Expansion Valve4.19.1 Valve Replacementa. Pump down low side of the unit. (Refer to paragraph4.5.1)b. Remove insulation from expansion valve bulb. (SeeFigure 4-13 and Figure 4-14.)c. Loosen retaining straps holding bulb to suction lineand detach bulb from the suction line.d. Loosen flare nuts on equalizer line and disconnectequalizer line from the expansion valve.