Panasonic CS-MA90KE Service Manual

Panasonic CS-MA90KE Service Manual Manual pdf 43 page image

– 42 –CS-MA90KE2. Diagnosis methods of a malfunction of a compressor and a 4-way valveNature of faultInsufficient compressing of acompressorLocked compressorInefficient switches of the 4-way valveSymptom1. Relationship between the condition of the air conditioner and pressure andelectric currentCooling ModeCondition of the airconditionerInsufficient refrigerant(gas leakage)Clogged capillary tubeor StrainerShort circuit in theindoor unitHeat radiation defi-ciency of the outdoorunitInefficientcompressionLow Pressurel Carry out the measurements of pressure, electric current, and temperature fifteen minutes after an operation isstarted.l Electric current during operation becomes approximately 20% lower than thenormal value.l The discharge tube of the compressor becomes abnormally hot (nor-mally 70 to 90°C).l The difference between high pressure and low pressure becomesalmost zero.l Electric current reaches a high level abnormally, and the value exceeds thelimit of an ammeter. In some cases, a breaker turns off.l The compressor is a humming sound.l Electric current during operation becomes approximately 80% lower thanthe normal value.l The temperature difference between from the discharge tube to the 4-way valveand from suction tube to the 4-way valve becomes almost zero.Troubleshooting GuideHeating ModeHigh PressureElectriccurrent duringoperationLow Pressure High PressureElectriccurrent duringoperation