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HA-8 < SYMPTOM DIAGNOSIS > REFRIGERATION SYSTEM SYMPTOMS SYMPTOM DIAGNOSIS REFRIGERATION SYSTEM SYMPTOMS Trouble Diagnosis For Unusual Pressure INFOID:0000000009718613 Diagnose using a manifold gauge whenever the system’s high and/or low side pressure(s) is/are unusual. The Symptom Table INFOID:0000000009718614 Gauge indication Refrigerant cycle Probable cause Corrective action Both high and low-pressure sides The pressure returns to nor- Excessive refrigerant charge in Reduce refrigerant until speci- Air suction by cooling fan is in- Insufficient condenser cooling ↓ 1. Condenser fins are 2. Improper fan rotation of • Clean condenser. if necessary. • Low-pressure pipe is not cold. • When the compressor is stopped the high-pressure kg/cm 2 , 28 psi). It then de- creases gradually thereaf- Poor heat exchange in con- ↓ Air in refrigeration cycle. Evacuate repeatedly and re- Engine tends to overheat. Engine cooling systems mal- Check and repair each engine • An area of the low-pressure pipe is colder than areas • Low-pressure pipe is some- times covered with frost. • Excessive liquid refrigerant on low-pressure side. • Excessive refrigerant dis- charge flow. • Expansion valve is slightly open compared with the ↓ Improper expansion valve ad- Replace expansion valve. High-pressure side is too high and Upper side of condenser and High-pressure tube or parts lo- • Check and repair or replace malfunctioning parts. • Check lubricant for contami- nation. AC359A AC360A |