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  1. #1
    Join Date
    Aug 2007
    Location
    Winter Haven, FL
    Posts
    4,380

    Here is a fun one (puzzler)

    I get a call for a WIF only holding 20 degrees. I get to the site and look at the condensor. Older Techumseh condensing unit, bristol compressor (3hp) mated to bohn evap. The first thing I notice is the rusted 405 drier, but protecting this is a 053 drier. The output of the 053 is just about to sweat, dew point was about 73, ambient of 96. The compressor is marked "409" on top. I was almost out so I went to the shop and picked up a fresh can. I get back and compressor was off on thermal. I cooled it off and still wouldnt start. Found bad run and start cap. I put on a new start relay for good measure. I pump down the system (what already wasnt sitting in the condensor). It ran about 30 seconds and hit the bypass. I get the yellow dog and pull out 3 lbs. Cut the driers out, the 053 had come apart and most of the innards fell out on the concrete. At least the other drier was there. I put a 163 in and vacuum the system. Lots of moisture came out, as it took 1:15 to bring the low side of the system to 500 micons. I fire the system up and watch the pressures. After 10 mins I had 195/45. 105* on liquid line, 50* on suction. I decide to check and see if the fans kicked on early or what else was going on.
    No fan action, no frost on anything. I hear the refrigerant hissing through the txv. I opened up the valve untill the hissing stopped. Go back and check pressures. 180/35, 37* suction temp. Upon the discovery of the negative superheat numbers, I go and talk to the maintenance man,(this is a hotel). He tells me that he doesnt mess with it much, he did find a leak at the flare fittings on the receiver and drier. He tightened the nuts, the chief engineer is the one who filled it back up. He shows me the empty can of 409 in the storage room. Its empty, not even residual is left in the can. I wait another 1/2 hour to see if the box pulls down. Box is at 30 after 1 1/2 hours of run time. It started at 40. I run a pumpdown test. It gets to 10", although a little slow after 5 psi. I tell mgmt to call in the morning if box. Next morning box is at 20*. 180/25 27* suc temp. I pull another pump down test and the compressor cant get below 10 psi.

    Any guesses? The answer is disturbing....

  2. #2
    Join Date
    May 2000
    Location
    Monmouth Junction-NJ-USA
    Posts
    6,038
    If there was that much moisture in just the lines, why did you not dump the entire charge and pull vac on entire system??? That way you could start from scratch and know that it was not grossly overcharged also.
    If you really know how it works, you have an execellent chance of fixin' er up!

    Tomorrow is promised to no one...

  3. #3
    Join Date
    Aug 2007
    Location
    Winter Haven, FL
    Posts
    4,380
    Thats a good point, but you need to be sure of the problem before you go and dump 10 lbs of 409.
    But that was not the cause of the problem...

  4. #4
    Join Date
    Apr 2002
    Location
    most of the time in the Philippines
    Posts
    1,211
    R4909A? What was the original refrigerant? What TXV does it have? R409A is an R-12 substitute. R408A is an R502 substitute.

  5. #5
    Join Date
    Aug 2007
    Location
    Winter Haven, FL
    Posts
    4,380
    Quote Originally Posted by jhd1234 View Post
    R4909A? What was the original refrigerant? What TXV does it have? R409A is an R-12 substitute. R408A is an R502 substitute.
    Your getting warm.....

  6. #6
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,928

  7. #7
    Join Date
    May 2000
    Location
    Monmouth Junction-NJ-USA
    Posts
    6,038
    Quote Originally Posted by Joe Harper View Post
    Thats a good point, but you need to be sure of the problem before you go and dump 10 lbs of 409.
    But that was not the cause of the problem...
    May not have been the problem but it sure as hell is not doing the system any good.......What flavor did the X valve label indicate??????
    If you really know how it works, you have an execellent chance of fixin' er up!

    Tomorrow is promised to no one...

  8. #8
    Join Date
    Jul 2004
    Location
    NJ
    Posts
    1,802
    Why don't you tell us what the compressor and TXV were instead of giving dew point and stuff ?

  9. #9
    Join Date
    Sep 2007
    Location
    NH
    Posts
    1,216
    He charged the 409a as a vapor...

    "the chief engineer is the one who filled it back up. He shows me the empty can of 409 in the storage room. Its empty, not even residual is left in the can."

    unless it was the whole can then it wouldn't matter..

    But i'm with the other's check the TXV label who use's 409 in a walk in freezer..

  10. #10
    Join Date
    Aug 2007
    Location
    Winter Haven, FL
    Posts
    4,380
    The compressor was a med temp a/c bristol. Sitting in the opposite corner of the storage room was an empty can of 408. The txv has a 502 powerhead. The top of the box that held the 409 did not have a mark on it. The compressor was changed out two years ago, and filled with 409 and a 052 drier.

    Condensor condemed......

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