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Thread: txv iced up...

  1. #1
    Join Date
    Apr 2004
    Posts
    48

    Question

    Any wisdom is appreciated...this is regarding a small under-counter refer./ cooler in a nursing home commercial-type kitchen. (I will provide manufacturer if needed as I don't have that info: SORRY...)

    My MAIN CONCERN is this: can a (partially) iced-up / frosted txv and line into the evaporator cause suction psig to drop to 0 lbs.or more ( into vacuum) ??

    Unit runs on R12 and is not cooling at all...

    Thanks for any info; I will provide more stats/info as needed...

  2. #2
    Join Date
    Dec 2003
    Location
    Location!, Location!
    Posts
    929
    Head pressure?
    air-cooled?

    A restricted or faulty TXV can cause that, as can a low charge. I think your statement is a bit backwarsd. The visual clue as more likely the effect of your problem rather than the cause.

  3. #3
    Join Date
    Apr 2004
    Posts
    48
    Thanks rimek. You are correct my txv quiry is 'backwarsd'- on purpose, to trace to source of problem. I think I jumped the gun and didn't let the txv thaw out completely and then recheck psi, I didn't realize it would run low-side into vacuum-land...Unit runs fine (for now)- it needs a new t-stat. Oh yes, it is air-cooled and head pressure was fine, but any other comments you have re: this are sure welcome...thanks again!

  4. #4
    Join Date
    Aug 2003
    Posts
    30
    evaporators being dirty is a common low pressure problem which causes every thing to freeze.

  5. #5
    Join Date
    Feb 2005
    Posts
    10
    If the evap is Saran Wrapped can cause the same thing.
    Hate those under-conter things. :-(

    Sounds like you have it under control tho.

  6. #6
    Join Date
    Apr 2004
    Posts
    48
    'user99,' thanks; our cooks are great about 'containering' things besides the state of Kansas REQUIRES it...unit's running fine now...

    'dum one,' thank-you, I did check evaps. at the first and they were/are 'clean as a whistle...'

    By the way, how come filters are not installed in these and other food service stuff..?

  7. #7
    Join Date
    Aug 2001
    Posts
    200
    If only the TXV and the distributer lines are frosted, then check your superheat. The TXV is starving the evaporator. Adjust for proper superheat. If the suction pressure does not rise after you adjust the TXV, then you probably have a partially clogged TXV, probably clogged strainer. You may also have a partially clogged suction filter drier. The other thing you want to check is for a under charge, If the unit has a headmaster valve and the charge is low, it will not be able to maintain a proper condensing temperature and this will result in a very low suction temperature, almost 0 psi in some cases but not in a vacuum.

    [Edited by sgosine577 on 02-25-2005 at 11:18 PM]

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