Testing Compressor Discharge Valves
- Close the liquid valve in the receiver outlet and collect the refrigerant.
- The compressor will stop on LP trip.
- Shut the suction and discharge valves quickly.
- Observe the suction and discharge pressure gauges. If the discharge pressure falls roughly by 1 bar and above in five minutes and simultaneously if suction pressure rises, then the discharge valve is leaking.
Testing of Compressor Suction Valve
- Run the compressor under manual control.
- Close the suction valve slowly to prevent foaming of lubricating oil in the crankcase.
- With the suction valves shut, the compressor should develop a vacuum of 0.4 bar or more.
- This indicates the suction valves are ‘holding’ and functioning correctly.