Indication:
• 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:
• 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 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.
How to ensure air is removed
• Pumping down, close condenser inlet valve, cooling water at full flow, when cw
inlet and outlet temp become equal,
see what is the condensing pressure and from compressor suction gauge find out
saturation temp at that
corresponding condensing pressure, if it is equal to cw temp then it means air
has been removed.Restart the
compressor with all safety precautions.
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