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heatpump in heating mode pressure 80/330. changed out reversing

My friend installed a gibson heatpump air to air. He said in morning recently for heating in Northern minnesota here, it would make an offal noise and pipes would raddle. He took system pressure and they were off the wall . Low side 100 and high 450. We recovered the refrigerant and changed out the reversing valve and checked the orifice. Pulled a deep vacuum and weighed a charge in 10lbs as per name plate. Now noise has gone away and system working good but pressures in heating mode still 80/340. This is a r-22 sytem. Any suggestions would help.


  • Eugene Silberstein 3
    Eugene Silberstein 3 Member Posts: 1,380
    For design conditions...

    For design conditions, these pressures would seem to be high. In order to properly evaluate the system, though, additional information is needed. Please provide: outdoor ambient temperature, outdoor coil outlet temperature, indoor air temperature, indoor coil outlet temperature, return air temperature, supply air temperature and the temperature of the suction line at the inlet of the compressor. By the way, what is the nameplate capacity of the system?
  • Eugene Silberstein 3
    Eugene Silberstein 3 Member Posts: 1,380
    Consider this...

    With an outdoor temperature of 50 degrees and indoor temperature of 70 degrees, you would expect the following:

    Low side pressure in the range of 40 psig and a high side pressure in the range of 196 psig for a standard efficiency system. The numbers you provided seem very, very high.

    The temperatures I asked you to provide will enable you to calculate the system subcooling and the evaporator superheat to determine what is happening with your system.

    Using pressures as the sole method of charging and evaluating system performance is a big NO NO.
  • don_163
    don_163 Member Posts: 67

    are you out there? I guess he could think of this way too.
    If you have 320 psi on the highside then that means you got at least 100 degree ambient air at the return.

    Thats remind me of a ac I once had at a service station with
    all glass wall,icemaker and soda machine with inside condenser putting out about 36000 btu of heat on a 95 degree
    day and my highside pressure was riding very close to safety

    5 ton system trying to carry the load.I dont know maybe it from lack of people skill but, it took me 5 trip and 10 bags
    of ice customer supply to finally convience him into adding a bigger unit.

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