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  1. #1
    Join Date
    Feb 2013
    Location
    Lamar, SC
    Posts
    521

    Leak Checks and Pressure Tests

    I have read a few posts on here stating that to check R410A systems techs run the nitrogen up to 350 psig. Some say 200 psig and I haven't really seen anything yet about R22 (I usually go with the max test pressure on the template, if I can). My problem is my regulator will only give me about 165 psig max. I brought it up to the service manager today and he said he might could get the owner to buy new ones capable of the higher ranges but he wanted something in writing that there was a benefit to the higher pressure testing. I have no idea for where to find such a document, and our service manager doesnt know anything about HVAC, so me trying to explain that testing at closer to the operating pressures did not work. Any body have a clue where I could find something to print and show?
    "If you've eliminated all other possibilities whatever remains must be the truth."

  2. #2
    Join Date
    Feb 2010
    Location
    Calgary, Alberta
    Posts
    1,101
    In my experience, a leak will show itself at any test pressure, I think guys use higher pressures so a leak will be exposed faster and is easier to find.

    Take gas lines for example. A typical residential line is tested at 15psi. If there is a leak, it will show.
    Try using a digital pressure gauge when testing, it makes pressure drops easier to see.

  3. #3
    Join Date
    May 2012
    Location
    Upper Michigan
    Posts
    3,588
    Look in an install manual, the last few I did say right in them the pressure to test at which is 300ish, it's been awhile lol. so the Benefit is your doing it right and you can sleep at night.

  4. #4
    Join Date
    Dec 2003
    Location
    Citrus County, Florida
    Posts
    1,507

  5. #5
    Join Date
    Feb 2013
    Location
    Lamar, SC
    Posts
    521
    That was actually the post that motivated me try an get them to get different regulators because I just had a job with a 410 unit and the only leak I could find was a very small one at the suction line isolation valve but I am not 100% sure that leak was adequate for explaining the system needing recharging every year, especially since it has a cap (although the caps are crap and dont have o-rings). I hate second guessing myself and I will worry about that dang job for a year now.
    "If you've eliminated all other possibilities whatever remains must be the truth."

  6. #6
    Join Date
    Nov 2011
    Location
    Charleston, Wv.
    Posts
    1,461
    use a vacuum gauge like the bluvac....you'll know immediately if you have a leak...tiny or not.

  7. #7
    Join Date
    Jan 2005
    Location
    Houston TX
    Posts
    874
    I am not a scientist, but I would imagine it would depend on the actual structure of the R-410a compound molecule as compared to the nitrogen molecule. If I could I would use a 50 psi charge of helium. As it is the lightest gas available that is still an inert gas (non-flamable) . Many manufactures use helium for factory leak test, especially in absorbers and we know how tight they have to be. _GEO
    Once in a while everything falls into place and I am able to move forward, most of the time it just falls all over the place and I can't go anywhere-GEO

  8. #8
    Join Date
    Nov 2011
    Location
    St. Louis
    Posts
    3,319
    Quote Originally Posted by syndicated View Post
    In my experience, a leak will show itself at any test pressure, I think guys use higher pressures so a leak will be exposed faster and is easier to find.

    Take gas lines for example. A typical residential line is tested at 15psi. If there is a leak, it will show.
    Try using a digital pressure gauge when testing, it makes pressure drops easier to see.
    15 PSI for a resi gas line? How many leaks do you find versus the one you create? Did you mean 15" WC?

  9. #9
    Quote Originally Posted by hurtinhvac View Post
    15 PSI for a resi gas line? How many leaks do you find versus the one you create? Did you mean 15" WC?
    he means 15 psi. It's no the supply pressure.
    Any pipe can hold that pressure and you won't cause leaks.

  10. #10
    Join Date
    May 2004
    Location
    Salt Lake City/Tooele
    Posts
    2,454
    This should answer all your questions...straight from Copeland's mouth.
    http://lvhvac.com/cope_bulletins/1177.pdf

  11. #11
    Join Date
    Feb 2013
    Location
    Summerville SC
    Posts
    117
    Quote Originally Posted by Joehvac25 View Post
    Look in an install manual, the last few I did say right in them the pressure to test at which is 300ish, it's been awhile lol. so the Benefit is your doing it right and you can sleep at night.
    I believe tranes hyperion air handlers say 150 psi so don't use there documents haha. but I believe either Mitsubishi or fujitsus manual says a minimum of 200 psi. you always can ask the famous rundawg for some document I haven't seen anything he didn't have or couldnt find!
    "only 2 tools any man needs is wd40 and duct tape. if it moves and it shouldn't use the duct tape. if it doesn't move and should, use the wd40" -unknown

  12. #12
    Join Date
    Feb 2013
    Location
    Lamar, SC
    Posts
    521
    Prime example today, went on a no cool call this morning, found the unit had about 5 psi of refrigerant left in it, R410a. I added about half a pound of 22 and run the nitrogen in as high as my regulator would let it, 165 psi. I searched for a leak for about an hour and a half and found nothing. went back to the condenser and gauges still said 165. Now after the talk I gave the customer why it was important to do a leak check for $xxx/hour, I had to go back and explain I could not find one, it must be small, recommended injecting dye. So from this I could determine:

    1) Since the machine was practically empty, it must have a leak.
    2) If it held 165 psi nitrogen for 90 minutes without budging, it must not leak at 165 psi
    3) the unit held a 450 micron vacuum for 10 minutes, so based on number one that means nothing.
    4) To properly check a 410 system for leaks, you have to be able to put at least as much pressure on it as it operates at.

    If it were not for discovering the system empty, I would have said it had no leaks.
    "If you've eliminated all other possibilities whatever remains must be the truth."

  13. #13
    Join Date
    Jan 2007
    Location
    Mn the state where absolutey nothing is allowed
    Posts
    1,349
    Quote Originally Posted by jmsmars1 View Post
    I have read a few posts on here stating that to check R410A systems techs run the nitrogen up to 350 psig. Some say 200 psig and I haven't really seen anything yet about R22 (I usually go with the max test pressure on the template, if I can). My problem is my regulator will only give me about 165 psig max. I brought it up to the service manager today and he said he might could get the owner to buy new ones capable of the higher ranges but he wanted something in writing that there was a benefit to the higher pressure testing. I have no idea for where to find such a document, and our service manager doesnt know anything about HVAC, so me trying to explain that testing at closer to the operating pressures did not work. Any body have a clue where I could find something to print and show?
    what leak detector are you using?

    and, your company hired a SERVICE MANAGER that doesnt know anything about HVAC?????????

    what a great idea..............
    my boss thinks its possible to repeal the laws of physics

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