This may cause the refrigeration compressor to overheat, with a high discharge pressure and normal condensing temperature.
There are possibilities of small air bubbles in the liquid sight glass of the condenser.
Condensing pressure of the refrigerant in the condenser may be high.
If there is excessive air, it may reduce the cooling capacity of the system, making the compressor to run for the extended period of time.
It may cause the gauge pointer of the condenser to jump indefinitely.
Causes air in the refrigeration system :
During charging, air may enter in to the system.
If Freon-12 is used air may leaks in to the suction line because the working pressure of the Freon-12 refrigerant is less than the atmospheric pressure.
Action air in the refrigeration system :
Air in the system can be removed by collecting the system gas in the condenser, leaving the condenser cooling water on and venting out the air from the top of the condenser because air will not be condensed in the condenser but remains on top of the condenser above the liquid refrigerant.
Connect the collecting cylinder to the purging line of the condenser, open the valve, and collect air in the cylinder.
After purging the air from the system don’t forget to shut the purging valve.
Check the level of the refrigerant in the system. If required, charge the system with fresh refrigerant.
Restart the compressor with all safety precautions.