Truck/Trailer Refrigeration Unit - Sunbelt Transport Refrigeration

INDICATION/TROUBLEPOSSIBLE CAUSESREFERENCESECTION3.3.10 Expansion Valve MalfunctionLow suction pressure withhigh superheatLow refrigerant chargeExternal equalizer line pluggedIce formation at valve seatWax, oil or dirt plugging valve or orificeBroken capillaryPowerassemblyfailureorpartialLoss of element/bulb chargeSuperheat setting too high4.8/4.10Clean4.94.304.30ReplaceReplace4.30Low superheat and liquidslugging in compressorSuperheat setting too lowExternal equalizer line pluggedIceholdingvalveopenForeign material in valvePin and seat of expansion valve eroded orheld open by foreign material4.30Open4.9Clean4.30Fluctuating suctionpressureImproper bulb location or installationLow superheat setting4.304.30High superheat Broken capillary 4.303.3.11 Solenoid Valve MalfunctionSolenoid valve does notfunction properlySolenoid valve closes butrefrigerant continues to flowNo power to valveImproper wiring or loose connectionsCoil defectiveValve improperly assembledCoil or coil sleeve improperly assembledMovement of plunger restricted due to:a. Corroded or worn partsb. Foreign material lodged in valvec. Bent or dented enclosing tubForeign material lodged under seatDefective seatCheckCheck4.184.184.184.184.184.18CleanReplace3.4 Standby Motor MalfunctionStandby motor fails to startMotor contactor (MC) defectiveMotor Overload (OL) openImproper power supplyOil pressure switch (OPS) openSelector switch (SSW) defectiveReplaceReplace motor1.6CheckReplaceStandby motor starts, then stopsMotor Overload (OL) openHigh amperage draw1.6Check62-028843-6