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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."
Professional Member*
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.
Professional Member*
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.
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Professional Member*
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.Originally Posted by Gunslinger
"If you've eliminated all other possibilities whatever remains must be the truth."
Professional Member*
use a vacuum gauge like the bluvac....you'll know immediately if you have a leak...tiny or not.
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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
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15 PSI for a resi gas line? How many leaks do you find versus the one you create? Did you mean 15" WC?
Banned
he means 15 psi. It's no the supply pressure.
Any pipe can hold that pressure and you won't cause leaks.
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This should answer all your questions...straight from Copeland's mouth.
http://lvhvac.com/cope_bulletins/1177.pdf
Professional Member
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
Professional Member*
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."
Professional Member
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
Professional Member
I was wondering about that, a service manager that doesn't know the trade hes managing. Good luck.
Professional Member
Here's what I do, take it or leave it.
If no history is available on the unit I just recharge it and tell the customer that I put 'x' amount of refrigerant in and that we don't know what the situation is as far as leaks until we have some more info, depending on how long it takes for you to come back(if at all) you now know an approximate leak rate. 3 years, slow leak. 3 months, fast leak. If 3 months add nitro, I go up to 150psi on both 410-a and r-22 but I use DC gauges which go down to tenths and give it a good 30 minute or longer pressure test, depends on if I can run more calls while it sits. I've done 24 hours before. If its barely leaking check schraders and service valves first , found a lot of schraders leaking slowly. If you check the whole system and nothing is showing anything but the evap coil(assuming copper) is looking rough then it's most likely the evap coil.
Professional Member*
Sched 40 black pipe is rated to 125 psi.
Code mandates pressure tests on res. gas lines to be done at a minimum of 15 psi.
Soo..... What are you talking about?
Professional Member*
I am using a Robinair 16600, and Big Blu soap bubbles. He used to work at the gas company selling fireplaces is what i was told, he is more there for sales than anything else, gets our restock for the vans, sometimes, handles vehicle maintenance, sometimes, if you fuss enough. Been trying to get the oil changed in my van for 7000 miles now...
I know my detector isn't the best and I would like another one, but we are required to purchase our own tools and barely make a living wage. The only things the company supplies are: van, torch, nitrogen regulator, recovery machine. I am the only person in our company that even owns a vacuum gage.
"If you've eliminated all other possibilities whatever remains must be the truth."
Professional Member
I had an r-22 unit one time that was low. oil all over the place. thought hmm easy find charge it with nitrogen 150 psig then 250 still held. finally 350 and still held. I was stumped until I started moving pipes then I heard the little hiss. found it at the discharge of the compressor after the 90 bend no joints all one tube.. must of been getting hot due to a bad cond fan and then overheated that piece..
Professional Member
We have a municipality that requires us check our gas lines at 60psi!!!
The other ones require 14-20psi.
Professional Member
www.bacharach-inc.com/h-10g.htm
I can find ANY leak with this leak detector at 30 psi. My old boss would buy cheap detectors because he'd bill customers for multiple refills. When I got this I used to take it outside, let it warm up, set it very sensitive, and when I walked into a store I could detect if there was a leak anywhere in the building. NO KIDDING!
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