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  1. #1
    Join Date
    May 2008
    Posts
    370

    compressor changeout

    Bryant 5 ton hp - compressor shorted, trips breaker. I installed warranty compressor today. Unit is 4 years old. Pulled deep vac - 13 lbs r22 on nameplate. It sucked up 6 lbs prior to start up. 70 degrees today, so I started up in the cooing mode, closed high side gage and proceeded to finish weighing in charge via suction port. Unit will not take more. Moreover, when I close low gage pressure sits steady at 100+ psi and does not drop - seems to be no suction. Head pressure is about the same, best I remember. Compressor is starting and pulling 11 amps. Compressor is getting very warm. Discharge line is pretty warm. I changed LL filter also. Unit is frosting at the suction valve (may be normal). Both valves are open. I never closed them, by the way. But I checked just the same. I suspected RV. Pulled disconnect and unplugged RV as it was still energized in the cooling mode. I did not hear it shift - no pressure relief - like I usually hear when one is de-energized. If I had bad expansion valve, unit would suck to zero. Any ideas?
    td55

  2. #2
    Join Date
    Feb 2011
    Location
    Southeast America
    Posts
    14
    check ohms on the RVS.....it could easily just be the coil [so you wouldn't have to "open" the system otherwise...a shortcut....troubleshoot

  3. #3
    Join Date
    May 2008
    Posts
    370
    I pulled the connector off the RV solenoid. I can hear it energizing. the coil is good.
    td55

  4. #4
    Join Date
    Feb 2011
    Location
    Southeast America
    Posts
    14
    does sounds like the remaining 22 inside the system is stuck...the elimation troubleshooting tree looks like one is crossed out on the RVS coil....as with other items you noted...seems to me the 22 is held inside the evaporator or perhaps the metering flow has jammed or clogged with tiny bits of stuffs...

  5. #5
    Join Date
    Oct 2011
    Location
    between here and over there
    Posts
    453
    More info please, such as pressure, temps, superheat, subcool, metering device, ect, ect, thank you.

  6. #6
    Join Date
    May 2008
    Posts
    370
    ok. First I can't check SH or SC - system needs 13 lbs r22. I can only get it to "gravity fill" 6 lbs after pulling vac. Nameplate charge 13.4 lbs. That is what I pulled out before I swapped compressors. Problem is I cant get it to pull any suction to get it properly charged. Suction port is frosting meahwhile. Compressor is getting hot meanwhile. Has a txv. I changed this txv twice 4 years ago. I have since installed this condensing unit (4 years ago). When the txv went bad, the suction pulled down very low (0 psi) . When I try to add refrigerant the low gage goes above 100 (normal) - looks like it is taking Freon. But I notice the scales are not dropping, so I checked my scales (got out my hanging scales). Unit is not taking Freon. And when I close the blue gage (low side) pressure does not drop below 100. Sits still actually - no suction. I can hear compressor start. Checked amps - 11 amps. I can hear the RV clicking when energized - but no pressure shift> (when I unplug RV coil). If the txv was shutting down, wouldn't I see a pressure drop in the evaporator? Wouldn't it still be taking Freon?
    td55

  7. #7
    Join Date
    Oct 2011
    Location
    between here and over there
    Posts
    453
    Quote Originally Posted by tonydykes55 View Post
    ok. First I can't check SH or SC - system needs 13 lbs r22. I can only get it to "gravity fill" 6 lbs after pulling vac. Nameplate charge 13.4 lbs. That is what I pulled out before I swapped compressors. Problem is I cant get it to pull any suction to get it properly charged. Suction port is frosting meahwhile. Compressor is getting hot meanwhile. Has a txv. I changed this txv twice 4 years ago. I have since installed this condensing unit (4 years ago). When the txv went bad, the suction pulled down very low (0 psi) . When I try to add refrigerant the low gage goes above 100 (normal) - looks like it is taking Freon. But I notice the scales are not dropping, so I checked my scales (got out my hanging scales). Unit is not taking Freon. And when I close the blue gage (low side) pressure does not drop below 100. Sits still actually - no suction. I can hear compressor start. Checked amps - 11 amps. I can hear the RV clicking when energized - but no pressure shift> (when I unplug RV coil). If the txv was shutting down, wouldn't I see a pressure drop in the evaporator? Wouldn't it still be taking Freon?
    so when you unplugged the RV it did nothing it did switch over to heat from cool or vise versa? what was your temps across the RV?

  8. #8
    Join Date
    Sep 2010
    Location
    miami,fl.
    Posts
    639
    this might be stupid but ive seen it happen plenty of times. im sure you checked it but im throwing this out there anyways. your low side gage is not peircing the low side or very little. what makes me say that is when you add refrigerant your low side stays above 100psig so it looks like the pressure is not going anywhere also you mentioned the suction port is freezing sounds like the refrigerant is misting through the valve core slowly. causeing it to act as a metering device and getting really cold.

  9. #9
    Join Date
    Sep 2012
    Location
    cape coral FL
    Posts
    40
    are you putting liquid in suction???

  10. #10
    Join Date
    Jan 2010
    Posts
    6,380
    Close your liquid line and see if it will pump down.

  11. #11
    Join Date
    Mar 2009
    Location
    Mid-Mo
    Posts
    3,596
    Quote Originally Posted by anthonyac1 View Post
    this might be stupid but ive seen it happen plenty of times. im sure you checked it but im throwing this out there anyways. your low side gage is not peircing the low side or very little. what makes me say that is when you add refrigerant your low side stays above 100psig so it looks like the pressure is not going anywhere also you mentioned the suction port is freezing sounds like the refrigerant is misting through the valve core slowly. causeing it to act as a metering device and getting really cold.
    Been there, done that. Luckily I realized it pretty fast.

  12. #12
    Join Date
    Jan 2013
    Location
    San Gabriel Valley, California
    Posts
    32
    ha ha ha ha ha ha ha, very very good, good idea, yes, good idea

  13. #13
    Join Date
    Dec 2008
    Location
    Buffalo NY
    Posts
    3,127
    Quote Originally Posted by fengshvac View Post
    ha ha ha ha ha ha ha, very very good, good idea, yes, good idea
    Feng's is back! Awesome!


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