T-365 6–4Low suction pressureIncorrect software and/or controller configuration CheckFailed suction pressure transducer (SPT) or evaporatorpressure transducer (EPT)ReplaceSuction service valve partially closed OpenFilter drier partially plugged Section 7.12Low refrigerant charge Section 7.3No evaporator air flow or restricted air flow Section 7.13Excessive frost on evaporator coil Section 6.6Evaporator fan(s) rotating backwards Section 7.14.3EEV control malfunction ReplaceFailed digital unloader valve (DUV) ReplaceSuction and discharge pressurestend to equalize when unit is oper-atingCompressor operating in reverse Section 6.14Compressor cycling/stopped CheckFailed digital unloader valve (DUV) Replace6.8 ABNORMAL NOISE OR VIBRATIONSCondition Possible Cause Remedy/Refer-ence SectionCompressorCompressor start up after an extended shutdown NormalBrief chattering when manually shut downCompressor operating in reverse Section 6.14Loose mounting bolts or worn resilient mounts Tighten/ReplaceLoose upper mounting Section 7.8.1Liquid slugging Section 7.13Condenser or Evaporator FanBent, loose or striking venturi CheckWorn motor bearings Section 7.11/Section 7.14Bent motor shaft Section 7.11/Section 7.146.9 MICROPROCESSOR MALFUNCTIONCondition Possible Cause Remedy/Refer-ence SectionWill not controlIncorrect software and/or controller configuration CheckDefective sensor Section 7.24Defective wiring CheckLow refrigerant charge Section 7.36.7 ABNORMAL PRESSURESCondition Possible Cause Remedy/Refer-ence Section
