Compressor HVAC: Testing and Inspection

Compressor malfunction will generally appear in one of four ways: noise, seizure, refrigerant leakage or low discharge pressure. Resonant compressor noises are not cause for alarm; however, irregular noise or rattles may indicate broken parts or excessive wear. To check for seizure, de-energize the magnetic clutch and check to see if the drive plate can be rotated. If rotation is impossible, the compressor is seized. Compressor gas leaks are very often caused by a defective or worn-out shaft seal. A small amount of compressor oil leakage from the shaft seal is normal. Only when a large leak is detected should the shaft seal be replaced. Oil leakage can at times be detected visually, while gas leak checking will require a gas leak detector. Low discharge pressure may be due to a faulty internal seal or a restriction in the compressor; or leakage of refrigerant somewhere else in the system.