Non-Condensables In Refrigeration System

AI Thread Summary
The discussion centers on the impact of non-condensables in refrigeration systems, particularly regarding their ability to disrupt the liquid seal at the condenser outlet. One HVAC technician argues that a sufficient quantity of non-condensables can circulate and compromise system performance, especially under high subcooling conditions. The challenge lies in understanding how these non-condensables can exit the condenser without affecting the liquid seal created by excess refrigerant. The conversation highlights the difficulties in diagnosing issues caused by non-condensables, which can behave unpredictably and hinder system operation. Proper maintenance practices, such as pulling vacuums and using filter driers, are emphasized as essential for preventing these complications.
Saturatedpsi
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Got a debate going on with some HVAC supertechs...One contends a sufficient quantity of non-condensables in a refrigeration system (vapor compression & med/hi temp application) will circulate "around" the system. He's saying with the "sufficient quantity", the liquid seal will be lost at the condenser outlet. He's also qualified the operating conditions of the system as having high subcooling, which I'll translate as more than 10°.

So, if you start out with a system that would normally run 10° subcooling, then add some non-condensables (sufficient or otherwise), that eventually find their way to the condenser, how can they exit the condenser or affect the "liquid seal" created by the excess refrigerant, that provides the liquid seal in the first place? And assume the refrigerant hasn't reached "critical point" which I believe is a safe assumption for a beer cooler or residential A/C. :biggrin:

Thanks in advance for your time and thoughts. :smile:
 
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I have found large amounts of non-condensables in two different systems in my career. It is the worst of all variables because it is out of the norm and difficult to catch in the act. It works sometimes is the electrical equivalent of a short circuit. The air or nitrogen will stop all progress at the metering device and then start working properly again at an undetermined time. An old timer taught me to blow the charge at the high point until liquid comes out similar to burping a radiator. That worked very well with a minimal loss of refrigerant. In the other case, I recovered the refrigerant and burped the air from the reclaim cylinder. Both systems worked for many years afterwards. This is why we pull vacuums and install filter driers. Both practices are part of standard procedure for good reason.
 
I think it's easist first to watch a short vidio clip I find these videos very relaxing to watch .. I got to thinking is this being done in the most efficient way? The sand has to be suspended in the water to move it to the outlet ... The faster the water , the more turbulance and the sand stays suspended, so it seems to me the rule of thumb is the hose be aimed towards the outlet at all times .. Many times the workers hit the sand directly which will greatly reduce the water...
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