Page 1 of 3 123 LastLast
Results 1 to 13 of 28

Thread: Mystery leak

  1. #1
    Join Date
    Jun 2003
    Location
    Tampa Bay, FL.
    Posts
    120

    Mystery leak

    Name:  ImageUploadedByTapatalk1347054232.629109.jpg
Views: 490
Size:  77.5 KB
    After half a day and trying everything I know, I finally admitted defeat and declared this unit unrepairable and sentenced her to death! I've had to recharge this unit 3 times this summer so I finally pulled it out of service to do a tear down in the shop. Leak detector found an evap leak with condensate pan still attached ( refrigerant pooling in pan) but once evap was out, I could not find it electronically. Nitro up to 235 psi with bubble soap and no luck. Finally, I submerged it in a garbage can of water but still no bubbles! Copper was very green so I'm attributing it to "green death". Wondering if anyone else has had impossible leaks to find?

  2. #2
    Join Date
    Feb 2012
    Location
    Toronto Canada
    Posts
    1,090
    It has to be Leaking somewhere. I have never had a leak that I couldn't find just ones that other company's gave up on.

    why didn't you put dye in the system after the 2nd Recharge?
    why not Nitro and soap complete system not just the Evap?

  3. #3
    Join Date
    Apr 2007
    Location
    T.C minnesota
    Posts
    12
    schrader valve?

  4. #4
    Join Date
    Jun 2003
    Location
    Tampa Bay, FL.
    Posts
    120
    I'm with you. It is leaking somewhere. I always find them too, but this one has me stumped. All my work is "in house" so if I don't want to repair it on site, I have the option of swapping it out and bringing it to the shop, so I don't use dye. Maybe I should though. Like I said, the leak detector went off in the condensate pan but couldn't pick it up when I removed evap from the cooler and I checked the condenser and line set as well. Condenser is pretty beat up so I started there first. My theory is that the copper has corroded to the point where it's leaking or weeping over a broad area that it can't be pinpointed but I'm reaching here. The cooler is 15 years old and near the gulf.

  5. #5
    Join Date
    Jun 2004
    Location
    new jersey
    Posts
    30
    After checking all the obvious places 4 times you need to do what I call ,stupid thinking, check in places that make no sense, I had a couple surprises in the past

  6. #6
    Join Date
    Apr 2007
    Location
    T.C minnesota
    Posts
    12
    Quote Originally Posted by coolerman View Post
    After checking all the obvious places 4 times you need to do what I call ,stupid thinking, check in places that make no sense, I had a couple surprises in the past
    I once had a leak through the wires of a pressure switch. Drove me nuts, got lucky finding it. i had disconnected the wires and they went into a puddle of water by accident and seen bubbles.

  7. #7
    Join Date
    Oct 2011
    Location
    between here and over there
    Posts
    453
    Ant nothing a little 22, nitro and a GOOD leak detector cant find. specially seeings that its a small unit. its not like working with residential where the lineset runs through a chase or through an attic. cmon get yourself together man ;P

  8. #8
    Join Date
    Jul 2010
    Location
    So-Cal
    Posts
    585
    Did you check the compressor?

    Sometimes the compressor leaks around the terminals or the welds where the compressor is welded togather leak.

  9. #9
    Join Date
    Jun 2003
    Location
    Tampa Bay, FL.
    Posts
    120
    134a, 240 psi nitro and tek mate leak detector then bubble soap and finally dunk tank with no luck. Been doing this a long time but this one had me stumped. Wondering if anyone has a theory other than "operator error". Is it possible to have multiple micro leaks so small that they won't bubble but unit will still lose its charge, possibly due to the molecular structure of 134a?

  10. #10
    Join Date
    Feb 2004
    Location
    Western New York
    Posts
    1,063
    Quote Originally Posted by stinkypinky View Post
    I once had a leak through the wires of a pressure switch.
    Please go into a little more detail on this. Do you mean the sensing tube, or do you actually mean the wiring?

    Just thought of another possibility- was it a unitary non-adjustable control?
    Experience is what you have an hour after you need it.

  11. #11
    Join Date
    Jun 2009
    Location
    DFW, TX
    Posts
    679
    I've heard of the encapsulated pressure switches leaking through the wires too. You check at the end of the wire and its bubbling.

    Also, if you said the hot gas condensate loop was going off on electronic leak detector, I'd start by replacing that. Like you said, I've seen them where the copper is corroded and leaking over the broad area of the condensate loop. If you spray bubbles, if won't "bubble up" but it will look like "fizz" forming on the copper lines.

    Another thing I've done: Cut apart evaporator, lineset, and condensing unit. Braze them shut and pressurize each with Nitrogen. Come back next day and see which section lost pressure. (the 2-3 times I've done this, I saw pressure drop after 15 minutes on one section and never had to come back the next day!)

  12. #12
    Join Date
    Jun 2003
    Location
    Tampa Bay, FL.
    Posts
    120
    I get all of what you guys are saying. Been there done that. What I'm proposing is there a scenario where a leak of 134a can't be detected due to microscopic leaks or multiple leaks over a broad area. If you read my initial post carefully you would remember that I found a significant leak with my leak detector in the evaporator while it was in the condensate pan but was unable to locate it once the evap was removed.

  13. #13
    Join Date
    Aug 2012
    Posts
    39
    Quote Originally Posted by hydra View Post
    I get all of what you guys are saying. Been there done that. What I'm proposing is there a scenario where a leak of 134a can't be detected due to microscopic leaks or multiple leaks over a broad area. If you read my initial post carefully you would remember that I found a significant leak with my leak detector in the evaporator while it was in the condensate pan but was unable to locate it once the evap was removed.

    I have encountered that before. A couple of times it was due to refrigerant traveling up the condensate pipe from a leak that was in the water evaporator tray. I wasted time and effort looking for a leak that appeared to be in the evaporator but ended up being in the water evaporator tray. However, I think this type of situation is one that you have also encountered.

    About 20 years ago I started having similar experiences as yourself, mystery leaks, and it was giving me grief. I learnt a lesson that proved to be valuable over time, especially concerning R134a.

    I have pressurised a leaking R134a system to above 200 PSI with R22 and nitrogen and found nothing. Then put R134a back in at 60 PSI and found the leak. I have also encountered leaks that only leaked when the evaporator was below or close to freezing as well.

    These situations didn't happen often but happened enough to make me realise that R134a is different to other refrigerants, when it comes to locating hard to find leaks. I never encountered real difficulties finding leaks on systems with other refrigerants. Never had leaks that were there one minute then gone the next.

    R134a appears to have a very small molecule, larger than R22 and nitrogen. So if an R134a system doesn't have any visible signs of a leak, and a leak isn't initially detected, I don't even consider using nitrogen or anything else. I just put more R134a in and run the system, either stopping the condenser fan to increase the condensing pressure or stopping the evaporator fans to lower the evap temperature (or both). After the temp and or pressure has reached the appropriate levels I then stop the system and recheck for leaks. I have never encountered a 'hard to find' leak that I could not find using that method. However, I have discontinued or not bothered searching for leaks due to the condition of equipment and installed new instead.

Page 1 of 3 123 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event