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Thread: Help

  1. #1
    Join Date
    Sep 2006
    Posts
    19

    Help

    I have a problem with the pressure on a unit.
    Suction 45-50 lbs
    Liquid line 210
    super heat 15
    sub cool 20
    return air 72
    supply air 54
    good amount of air flow.
    Can not get suction pressure up. I can't seem to figure out the problem(if i even do have one) Anybody have any ideas

  2. #2
    Join Date
    Dec 2000
    Location
    NW Ohio
    Posts
    516
    Type of unit, brand, model #, refrigerant might be helpful. Also maybe operating conditions.

  3. #3
    Join Date
    Aug 2006
    Location
    Mixing oil and fire with a big spoon.
    Posts
    4,006
    it appears that all is operating ok...even if i dont know exactly what you have. assuming txv and dx cooling coil, you are not getting the heat out of the coil and into the refrigerant...dirty coil on the air side or dirty tubes on the refrigerant side (like from an old burn out or something).

    a little more info would really help...i really hate assuming.
    It's tube brushing season...93% done (39.35 miles of tubing)...only 1,242 tubes to go!

    Original member of the Raccoon Brotherhood.

    EVERYTHING IS AWESOME!!!

  4. #4
    Join Date
    Mar 2005
    Location
    Pacific Time Zone
    Posts
    4,151
    What is your outdoor temperature? You subcool seems a bit high but if you have a low OAT then your subcool will be a bit high. I also really don't see anything wrong especially with the low high side pressure.
    "How it can be considered "Open" is beyond me. Calling it "voyeur-ed" would be more accurate." pka LeroyMac, SkyIsBlue, fka Freddy-B, Mongo, IndyBlue
    BIG Government = More Dependents
    "Any 'standard' would be great if it didn't get bastardised by corporate self interest." MatrixTransform
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  5. #5
    Join Date
    Dec 2006
    Location
    Oz
    Posts
    150
    sounds like a dirty evaporator (indoor) on a heat-pump.

  6. #6
    Join Date
    Mar 2005
    Location
    Pacific Time Zone
    Posts
    4,151
    Quote Originally Posted by tex~n~oz View Post
    sounds like a dirty evaporator (indoor) on a heat-pump.
    Granted we need more info. but why? A TD on the indoor coil of 18 deg and a superheat of 15 deg sounds great to me.
    "How it can be considered "Open" is beyond me. Calling it "voyeur-ed" would be more accurate." pka LeroyMac, SkyIsBlue, fka Freddy-B, Mongo, IndyBlue
    BIG Government = More Dependents
    "Any 'standard' would be great if it didn't get bastardised by corporate self interest." MatrixTransform
    http://threedevilskennel.com/ - not my website.
    Versatile Hunting Dog Federation - www.vhdf.org/


  7. #7
    Join Date
    Aug 2006
    Location
    Mixing oil and fire with a big spoon.
    Posts
    4,006
    Quote Originally Posted by crab master View Post
    Granted we need more info. but why? A TD on the indoor coil of 18 deg and a superheat of 15 deg sounds great to me.
    while the td's sound ok, it takes an evaporator saturation temp of 22F to 26F to get 54F leaving air. an evaporator saturation pressure of about 68 psig, gives you about 40F saturation temp, which would be closer to normal. it could be the very beginning of a leak/loss of charge but the high subcooling gives it away. probably not a leak. since there is very little heat transfer, the txv does not let much refrigerant into the low side. the refrigerant has to go somewhere, so it sits in the condensor and gives up all of it's heat so you get a lot of subcooling.
    It's tube brushing season...93% done (39.35 miles of tubing)...only 1,242 tubes to go!

    Original member of the Raccoon Brotherhood.

    EVERYTHING IS AWESOME!!!

  8. #8
    Join Date
    Dec 2006
    Location
    Oz
    Posts
    150
    Jayguy...

    I like the way you think. Spot on.

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