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I have Mcquay AC unit with R- 22 that only has a LL service valve. No suction or discharge do I top off while running?

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  • jmckeever446 Mar 28, 2011

    I just started working in this building. When I went to check out these units I discovered this. I never seen this before, no way to see suction psi. there is a sh.port on discharge. Do you have another suggestion on how to charge ?



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The only way to do that would be to heat the tank up with very hot water to the piont where the pressure in the tank is higher then the head pressure of the system while running.
Do it at the coolest time of the day so the head pressure is at it's lowest point...
Then also feed it in as a liquid so that you can get it in faster...

Just curious as to why there are no access points or service valves in the suction side of the you have no access to even check the low side pressure???
Does the unit run 24/7 ???

You may even have to set the tank up so that it is in a water bath and then you keep heat under it as in a burner of some type to keep it hot enough to overcome the high side pressures...seems like it could be kinda tricky to do, but possible...


Posted on Mar 28, 2011

  • D. Floyd Kolb
    D. Floyd Kolb Mar 28, 2011

    What type of compressor are they?? Sometimes you can actually charge through the oil port...what is the size of the units ??? Seems as though they sould be semi-hermetic type compressors that should have a crankcase and an oil port...the oil port is actually the suction side and it is possible to bleed refrigerant slowly into there...

    I was home for lunch and am headed back out, so I will not be getting back to you for a few hours now...



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