Truck/Trailer Refrigeration Unit - Sunbelt Transport Refrigeration

With the unit running, frontseat the suction servicevalve and pull a vacuum in the compressor crankcase.SLOWLY crack the suction gauge manifold valve and oilwill flow through the suction service valve into thecompressor. Add oil as necessary.c. Adding Oil to Service ReplacementCompressorService replacement compressors may or may not beshipped with oil.If compressor is without oil:Add correct oil charge (Refer to section 1.3) byremoving the oil fill plug (See Figure 4-14)d. To remove oil from the compressor:1. Close suction service valve (frontseat) and pumpunit down to 0.1 to 0.3 kg/cm@ (2 to 4 psig). Frontseatdischarge service valve and slowly bleed remainingrefrigerant.2. Remove the oil drain plug from compressor anddrain the proper amount of oil from the compressor.Replace the plug securely back into the compressor.3. Open service valves and run unit to check oillevel. Repeat as required to ensure proper oil level.811107961 21. High Pressure Switch Connection2. Suction Pressure Transducer Connection3. Suction Service Valve4.OilFillPlug5. Bottom Plate6. Oil Drain Plug7. Oil Level Sight Glass8. Oil Pump9. Unloader Solenoid10. Discharge Thermistor Connection11. Discharge Service ValveFigure 4-13. Compressor -- Model 05G345522CYLINDER1. Suction Service Valve2. Discharge Service Valve3. Oil Level Sight Glass4. Oil Drain Plug5. OilFillPlugFigure 4-14. Compressor -- Model 05K4.14 COMPRESSOR UNLOADER VALVEThe compressor unloaders (located on thecompressor cylinder heads) are controlled by relaysUFR,URR and the temperature controller. (refer toSection 1.12)a. Checkout Procedure1. Connect manifold gauges to the compressorsuction and discharge service valves and start unit incooling mode with the trailer temperature at least 5_F(2.8_C) above set point. The compressor will be fullyloaded (both unloader coils are de-energized). Notesuction pressure.2. Remove wiring from the front unloader coil.Placeelectricaltapeoverwireterminals.3. Set controller upscale (cooler to warmer). Thismechanically simulates falling temperature.Approximately 2_F (1.1_C) below box temperature, theunloader coils will energize, but only the rear unloadervalve will unload. Note suction pressure. A rise ofapproximately 3 psig (0.2 kg/cm@) should be noted on thesuction pressure gauge.4. Reconnect wiring on the front unloader. Thefront unloader will retract and an additional 3 psig (0.2kg/cm@) rise on the suction gauge will be noted.Compressor is now fully unloaded and only the top bankis loaded (two cylinders).5. Reverse the above procedure to checkcompressor loading. Suction pressure will drop with thistest.NOTEIf either unloader coil energizes and the suctionpressure does not change, the unloader assemblymust be checked.1344-15 62-02884