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  1. #1
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    clogged cap or low on gas?

    whats the easiest way to determine if residential frig has filter or cap clogged or low on gas from leak?

  2. #2
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    Start with Pull the charge and weigh it, move on from there.

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  4. #3
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    System should equalise pressure when switched off. If stays in a vacuum cap is plugged.
    The primary function of the design engineer is to make things difficult for the fabricator and impossible for the serviceman.

  5. #4
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    Sep 2003
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    Residential? Just buy a new one.
    Local 449?

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  7. #5
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    If a residentail frig has electrical problem, fix it, but when its got refrig problem, dont waste your time

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  9. #6
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    Aug 2013
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    I have a similar question with a Sub Zero under counter refrigerator. Going to dig deeper into it tomorrow but I did notice on visual inspection today the cap tube had frost starting about 6 inches from the evap coil. I'm a residential tech and I'm tinkering so any info on cap tube restrictions would be great. Would ice before the evap coil be a guaranteed restriction or could other issues cause that?

  10. #7
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    A restriction will be accompanied with a temperature drop at the point of restriction.
    If a drier for example feels normal on one end but cold or frosting on the other it's restricted.
    Usually a cap tube restriction will be on just one tube. If they all are plugged look at the distributor before the tubes. Some have a strainer there.
    Frost=pressure drop.
    Ice usually indicates the evap is too cold because it can't transfer to the load. Dirty coil, fan problem if there is one etc.
    Frosting back to the compressor, look at the charge. A restriction usually won't have the refrigerant capacity to frost much beyond the restriction.
    I know this is fairly general but frost is one thing and ice is another.
    I should have played the g'tar on the MTV. MK

    You can be anything you want......As long as you don't suck at it.

    SMW Lu49

  11. #8
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    Quote Originally Posted by targetman View Post
    Residential? Just buy a new one.
    Quote Originally Posted by Snapperhead View Post
    If a residentail frig has electrical problem, fix it, but when its got refrig problem, dont waste your time
    One caveat. If it's your own frig, you got the time, and have that burning desire to figure things out, then you play to your hearts content.

  12. #9
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    We're talking residential frig.

    Most of those things you mentioned don't apply.

    Like when they run the cap tube inside the suction line.

    Or solder the cap tube to the suction line.

    Or you can't even see half of the cap tube due to the construction of the box.



    Quote Originally Posted by hvacker View Post
    A restriction will be accompanied with a temperature drop at the point of restriction.
    If a drier for example feels normal on one end but cold or frosting on the other it's restricted.
    Usually a cap tube restriction will be on just one tube. If they all are plugged look at the distributor before the tubes. Some have a strainer there.
    Frost=pressure drop.
    Ice usually indicates the evap is too cold because it can't transfer to the load. Dirty coil, fan problem if there is one etc.
    Frosting back to the compressor, look at the charge. A restriction usually won't have the refrigerant capacity to frost much beyond the restriction.
    I know this is fairly general but frost is one thing and ice is another.

  13. #10
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    I'm going with Pecmsg on this one.

    But I would be curious what the suction pressure and subcooling is if after weighing it in. Especially if that doesn't get it to cool.


    Quote Originally Posted by pecmsg View Post
    Start with Pull the charge and weigh it, move on from there.

  14. #11
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    Quote Originally Posted by BBeerme View Post
    We're talking residential frig.

    Most of those things you mentioned don't apply.

    Like when they run the cap tube inside the suction line.




    Or solder the cap tube to the suction line.

    Or you can't even see half of the cap tube due to the construction of the box.

    That's why I said "Fairly general" All this applies when it can apply.
    I believe the difference between ice and frost needs to be understood because the ?? comes up a lot.
    I should have played the g'tar on the MTV. MK

    You can be anything you want......As long as you don't suck at it.

    SMW Lu49

  15. #12
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    A unit low on charge will usually frost up the cap tube a few inches before the evaporator JUST LIKE a restriction. Anybody thinking they can tell the difference visually will be as luck as flipping a coin. Might be right might not.

    How quickly pressures equalize is also an incredibly poorly unreliable way to diagnose a unit. A small block of ice on first row of evaporator will cause a unit that's low on charge to not equalize until the ice melts. Also how cold the evaporator is will determine how quickly pressures equalize, and to what pressure the equalize to. It's easy to mess up and leads guys down wrong path all the time.

    That being said, I don't service residential refrigerators other than a handful of SubZeros at commercial office buildings.

    Sent from my SAMSUNG-SM-G890A using Tapatalk

  16. #13
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    Jun 2012
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    If you have a critically charged refrigeration system, one with no access fittings and you install access fittings, you just unbalanced the system and will never get the same performance and economy as original. This is why you get the advice to fix electrical and replace if refrigeration side.

    That being said, I remember having a hydraulic tool that would chase a "pig" through the cap tube to remove obstructions. It did work most of the times. That was back when domestic refrigeration was more service friendly.

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