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  1. #1
    Join Date
    Jan 2001
    Posts
    765
    Repaired a refrigerant leak on condensor coil friday.had 200# nitrogen system dropped to 190 from friday till today.i jacked her up to 350 it does drop quicker but illbe ##### if i could find a leak. bubbles put somee 22 in her w/nitrogen and used my h-10g nothing.usually that will go crazy but i couldnt even find a trace.this is the old trane unit with splash coil.my boss says pull a vaccum if it pulls down good charge it up. any advice???the only thing I can think of is to try and isolate evap and condensor????

  2. #2
    Join Date
    May 2004
    Posts
    12,028
    H...


    I have many of the old Trane units with splash guards. They are famous for evap leaks. The only way we find them is 250# nitrogen and soap the u-bends and distributor tube connections. Problem is you can only check the front of the coil, not the back.

    If your system is 10+ years old, start there and look for the smallest leak you have ever found. Don’t stop with finding one leak. Where there is one you may find a nest full. If over 7 or 8 leaks, replace the coil or the unit. If you try to repair with 45% do not guarantee this fix.

    P.S. Patience it may take 5 or 10 to foam at the joint.

  3. #3
    Join Date
    Jun 2004
    Location
    Richmond Virginia
    Posts
    1,078
    If you had a mixture of 22 and nitrogen in the system and the outdoor temp was lower today than Friday then you can expect the pressure to drop some. The nitrogen pressure is not going to change much with the temp difference but the 22 will. Also, don't make it a practice to pressurize a unit with more than the test pressure. If you don't know the test pressure (it should be on the nameplate) then assume it is 150. I assume what your boss is saying is that he doesn't believe you have a leak and that when you pull a vacuum and use your micron guage you will be sure system is tight if you can pull a good vacuum. Are you still working on those SACA's trying to bring them back to life! What kind of hoses are you using, the pressure could have been right through them. I fear that you didn't have a leak or had a very small one and that you have made it worse by overpressuring the system. I worked on those units for years and the most common leaks I had were at the TXV distributor tubes entering the evaporator. They would leak where the 3/8" coil inlets were crimped around the 1/4" distributor tube inlets. Also had a couple leak around the bottom ubend at that end of the coil also. Good luck and I commend you for not just saying screw it and charging the unit up and walking away.

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