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checking for AC leaks with nitrogen
4020
Posted 4/13/2011 22:01 (#1723127)
Subject: checking for AC leaks with nitrogen
Has anyone used nitrogen for checking for leaks? If so, I would like to know the details of the procedure. Thanks in advance mdnelson86
Posted 4/13/2011 22:19 (#1723174 - in reply to #1723127)
Subject: Re: checking for AC leaks with nitrogen
Paxton, IL
I haven't done it but I've looked into it. basically you just need a nitrogen cylinder with a regulator. hook it up through your manifold gauges and pressurize the system making sure there is a little refrigerant in the system to escape so you can find the leak. I've heard it works really well especially on those pesky small leaks that are tough to find unless the system is under pressure. Gerald J.
Posted 4/13/2011 22:22 (#1723183 - in reply to #1723127)
Subject: Re: checking for AC leaks with nitrogen
The contractor that put in my new central air, filled the system with nitrogen to help dry it and to check for leaks. I didn't watch closely, probably set the pressure near full scale on a gauge and let it set a couple hours to see if the pressure changed. It would be hard to have a gas detector to find a leak, but a splash of soapy water on all the fittings would also show bubbles if there was a leak anywhere. Then they pumped out the nitrogen and put in the refrigerant and its worked fine. The boys doing the work made a point of telling me that not all AC contractors took the time to test and dry with nitrogen.
Gerald J. 4020
Posted 4/13/2011 22:31 (#1723210 - in reply to #1723174)
Subject: Re: checking for AC leaks with nitrogen
How much pressure can a system handle? I have seen pressures up to 400 pounds when the expansion valve was malfunctioning. I just wondered what the limit is. TP from Central PA
Posted 4/13/2011 22:39 (#1723241 - in reply to #1723174)
Subject: Re: checking for AC leaks with nitrogen
Tech at our dealer clued me into it last summer............All you need is a tank, regulator and fitting to adapt it to hook it up to the ac. Don't remember what pressure he put into the 4230, but he found a leak with it that putting it on a vacuum didn't show
(Actually was a rust pin hole and the vacuum pulled the rust into the hole which is why it didn't show
).............Got out his handy windex container with soap and it wasn't long before we spied it bubbling. mdnelson86
Posted 4/13/2011 23:03 (#1723323 - in reply to #1723127)
Subject: Re: checking for AC leaks with nitrogen
Paxton, IL
<p>I wouldn't put much more than 100psi on it. high pressure side runs a fair amount higher than that normally but low side should be much lower when it's running. the low pressure side should still handle quite a bit more than that but you don't want to take a chance at blowing stuff up......although if you did at least you'd know there was a leak there for sure :
) Again I haven't done it but I'd say 100psi is fine and should be enough to find most leaks. at least that's where I'd start. you could turn it up if you know you have a leak and you can't find it. just for reference on a 90 degree day the high pressure side will be running between 180 and 225psi</p>
Edited by mdnelson86 4/13/2011 23:05
msb
Posted 4/13/2011 23:17 (#1723373 - in reply to #1723127)
Subject: Re: checking for AC leaks with nitrogen
Lapel, In
You can do the same with ordinary compressed air. andserco
Posted 4/13/2011 23:21 (#1723386 - in reply to #1723373)
Subject: Re: checking for AC leaks with nitrogen
Hillsboro,Texas
compressed air has a moisture content, that is why nitrogen is the preferred way to leak test.. moonshine
Posted 4/14/2011 01:35 (#1723542 - in reply to #1723386)
Subject: Re: checking for AC leaks with nitrogen
Idaho
What about oxygen or CO2 which I have? Bunny2
Posted 4/14/2011 08:47 (#1723736 - in reply to #1723127)
Subject: Re: checking for AC leaks with nitrogen
We normally put 90 PSI of nitrogen into a system when looking for leaks
Edited by Bunny2 4/14/2011 08:48
yallardeere
Posted 4/14/2011 19:23 (#1724376 - in reply to #1723736)
Subject: Re: checking for AC leaks with nitrogen
you can pressure with propane''''''' KTA
Posted 4/14/2011 19:31 (#1724384 - in reply to #1723736)
Subject: Re: checking for AC leaks with nitrogen
Delco compressor relief valve cracks at 440 psi. When an expansion valve plugs rest assured it will open and nothing BLOWS up. We have used dry nitrogen for 20 years for finding leaks and it cures comeback/redo work problems. If a system will not hold 400 psi for a couple of hours then you need to fix it. Dry nitrogen is nonflammable, noncorrosive, cheap and since it makes up about 78% of the air you breathe, nonlethal. We have it to use in hydraulic accumulators so its a no brainer. silagehauler
Posted 4/14/2011 19:39 (#1724389 - in reply to #1724376)
Subject: I know thats a joke...
But propane is actually a pretty good refrigerant. I know of at least one farmer in the neighborhood that is, lets say infamous for running propane in his old white tractors.
He hasn't blown up yet, and in all reality, no more propane then there is a system like that, I would say the odds are definantly in his favor of not blowing up. 4020
Posted 4/15/2011 22:00 (#1726525 - in reply to #1724384)
Subject: Re: checking for AC leaks with nitrogen
Does it matter which port you put it in through? Do you just use soap bubbles to find the leak after you pressurize the system?