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Thread: poor cooling

  1. #1
    Join Date
    Jul 2005
    Posts
    27
    Does anyone know how you can diagnose a restricted distributer to the evap? Anyway, was called out for a lack of cooling call. evap was filthy and so was outdoor unit. supply air around 60 after 15 min of run time. hooked up and it definitely looked short. Ambient 95 suction 64 discharge 225. I charged a little in and the pressures came down, what's up with that. Anyone knows anything i would appreciate the help. Thanks

  2. #2
    Join Date
    Aug 2004
    Location
    Tyler TX
    Posts
    676
    You have to clean the unit in order for it to perform properly. What was your superheat reading before putting in some gas?
    HVAC Contractor, Tyler Texas.

  3. #3
    Join Date
    Mar 2005
    Location
    Suppy NC
    Posts
    4,513
    what was the super heat and sub cool. what was the td aceoss the coil,suction line temp liquid line temp
    was there enough airflo across the coil. need info the give answer. presure alone does not tell anyone if it is low on charge.

  4. #4
    Join Date
    Feb 2004
    Location
    mesa Az
    Posts
    15
    Need more info. Get the Super heat, sub cool, wet bulb temp
    Is there a serv. facts in the unit. It will tell if charge is ok. Check the blower wheel is it clean. Is this a pack or a split. With out this info you will not be able to properly diagnose this unit or any other unit.

  5. #5
    Join Date
    Feb 2005
    Location
    Central Alabama
    Posts
    466
    My thoughts on checking for restriction is take temperature reading where each refrigerant cicuit ends and if there is a rather large difference in readings then you will have your answer.

  6. #6
    Join Date
    Jul 2005
    Posts
    27

    poor cooling

    I admit I was in a hurry. Anyway, its a split coleman 3 ton. ambient 78
    return 74 degrees
    supply 56 degrees
    suct 60psi
    disch 187 psi
    liq line 94 degrees
    gauge high side 97 degrees
    suct line temp 35 degrees
    gauge low 33 degrees
    inlet evap 48 degrees
    outlet evap 38

    I took the td of evap last as I had to shut unit off to attach temp probes. Now I am not an expert so be easy on me if it seems I didn't get a correct reading. Also suction line is frosting up at service port. It seems to me that the evap is passing straight liq through, but thought I would ask the smart guys.
    Thanks for your help

  7. #7
    Join Date
    Feb 2005
    Location
    Central Alabama
    Posts
    466
    looking at the info given have you cleaned evaporator and checked filters? sounds like evap may be dirty or stoped up.

  8. #8
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,778
    As bama said you got an air flow problem

    Also may be be slightly over charged with your subcool being that low.

    But can't tell till you corrct air flow problem.

    Did you add gas to system trying to get vapor pressure up?

    If you want to check for a restriction at the indoor unit. Disable the blower and watch the distributors for frosting, they should all frost at the same time and rate.
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  9. #9
    Join Date
    Aug 2004
    Location
    Tyler TX
    Posts
    676
    When you clean the coil be sure not to forget to pull and clean the blower, i bet it will be as nasty as the coil
    HVAC Contractor, Tyler Texas.

  10. #10
    Join Date
    Jul 2005
    Posts
    27
    I did add some gas , not much because I didn't see pressures rise but instead fell. The air flow seems to really be blowing good out of registers but do not have a cfm meter. I cleaned the coil in place the best I could and made a hell of a mess but don't know if that is good enough as it was caked with crud. Also thanks for the tip on restricted header I will check that out.

  11. #11
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,778
    You might have to pull the coil and clean it, if the blower isn't all hogged up also.

    If the distributors aren't restricted.

    You might want to do a pressure drop test across the coil, that will tell you if the coil is still cruded up.

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  12. #12
    Join Date
    Jul 2005
    Posts
    27
    Just wanted to say thanks for all your help. As soon as I pulled the blower and cleaned it ,everything came back to normal. I also found a collapsed supply duct under the house which affected the entire right side of the house, that one hurt my brain. Anyways thanks again for your help.

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