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  1. #1
    Join Date
    May 2004
    Location
    Austin, TX
    Posts
    1,733

    Question

    I have an old Singer refigeration unit 10ton, with
    a coupland hermetic compressor, that is testing
    me. It is a 1976 unit, but compressor was replaced
    with a remanufactured unit in 1999.

    This unit runs on freon 409a, and is a high temp
    unit 38 degrees.

    The problem I am having is low high side pressure
    160psi, and very low low side 18" vacuum.

    The unit has no leaks, and is properly charged.

    I evacuated unit, and leak checked, all ok.
    Filter dryers are ok also, and valves all
    checked good. At these pressures, unit is only
    producing about 20%. At this building there are
    3 other Singer units 2 20 ton units, and another
    10 ton unit. I have replaced compressors in 2
    of the other 3 in the last 2 years, and no
    problems.

    The only item I have not checked is the expansion
    valve, because it is 25' up on a ceiling in a large
    cold vault surrounded by merchandise. But at
    these preasures I do not feel valve is stuck.

    Any ideas???

    Edward

  2. #2
    Originally posted by edward301
    But at
    these preasures I do not feel valve is stuck.
    Why not? L.L.S good?

  3. #3
    Join Date
    Jul 2000
    Location
    Guayaquil EC
    Posts
    10,374
    Is this sytem actually allowed to run at these conditions???? I should hope not or you'll be replacing another compressor real soon.

    No refrigerant is moving here. You have a major restriction of refrigerant flow. Trace it out......filter-drier, liquid line solenoid, TXV screen, TXV powerhead, stuck TXV.......

    Your going to have to get to the evap and the TXV one way or the other to fix this. Get the customer (or whoever) to break you a path and clear the area so you can work.

  4. #4
    Join Date
    Jan 2002
    Posts
    1,895
    You could try some animal sacrifice or a witch docter but if the coil hasn't been looked at common sence says there is where the problem probably is.

  5. #5
    Join Date
    Mar 2004
    Location
    Windsor, ON Canada
    Posts
    168
    If there is no lls, try adding a little refrigerant, if head goes up a little and suction continues in a vacuum, txv is stuck...guaranteed.

  6. #6
    Join Date
    May 2004
    Location
    Austin, TX
    Posts
    1,733

    Cool Singer refigeration unit fixed.

    Gained access to the evaporator unit 25' up, and found the
    problem. Whoever replaced the evaporator 5 years ago
    did not wire the unit in properly. An electric valve was
    intermittant, shutting off the flow of freon at random
    times. Rewired unit, now everything perfect. Cold as
    can be.

    Edward.

  7. #7

    Re: Singer refigeration unit fixed.

    Originally posted by edward301
    Whoever replaced the evaporator 5 years ago
    did not wire the unit in properly......Rewired unit, now everything perfect.
    Hmmmm, for 5 years ran great and now this shows up? Smoething's fishy in Gotham, Batman.

  8. #8
    WAY TA GO Edward!!!


    And welcome to the forum community.

    (watch out for DiceMan ... he attempts to intimidate newcomers)

    Seriously ....

  9. #9
    Join Date
    Apr 2005
    Location
    dallas texas
    Posts
    21

    AN Electric Valve?

    DO you mean the Pump Down Solenoid? Also if you Low pressure Cut out is set right it would not run In an 18 inch vacuum

  10. #10
    Join Date
    May 2004
    Location
    Austin, TX
    Posts
    1,733
    Wow, this post is so old I barely remember it. Those units are still running,
    doing quite well. One 20 ton unit did give me problems last fall, turned out
    the head pressure control valve had gone bad.

    New valve, doing good.

    I am adding a new 30 ton refigeration unit, except the freight company
    damaged the evaporator. They hit and badly bent the suction line
    exiting the evap cabinet, which in turn bent the copper line all the way
    up the evap coil.

    New evap on order, freight company bought the old one.

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