Re: non-condensable gas
Originally Posted by mallmk13
If there is non-condensables present OR there is excess refrigerant in the system then you will get the same symptoms. So you have to do a test called "non-condensable test".
The symptoms are :
High discharge pressure , High sub-cooling.
Now I explain the test.
Pump down the system and make sure that the low pressure setting is low enough to evacuate all the refrigerant from the evaporator. Now when the compressor stops, turn on the condenser fans for at least 30minutes. If there is water cooled condenser then turn on the pump and let the water flow.
Now measure air (water) inlet temperature into the condenser and record it. With this temperature go to the refrigerant pressure-temp table and find the corresponding pressure in Gauge pressure (not absolute).
Now compare this pressure with your gauge pressure connected to the system.
If P(discharge-system) >> P(from table) then you have non-condensables.
If P(discharge-system) = P(from table) then there is excess refrigerant in the system.
Remember : this test will not work if the receiver and condenser are in different places with different temperatures.
I hope this helps
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