Replywhat did you pressure it up to with nitro? did you isolate the system? did you use a leak detector? sounds like the system was hacked in at first,lol
Professional Member
Went to a job after other people had installed this complete unit and guages went on , low on freon .
Since the customer had enought of these " other" people , (i'm the # 3 man there ) i shut the Valves and proceded to test with nitrogen and left it for 1 Hr , even used soap to see "if" pinholes will show up . Nothingh .A course I finish the "other" problems ( bulb for expansion valve left hanging ) :
Here is the rest of the story : what got me was i was called by the same customer after 5 days and said he had some one else that found the leak ???
I would think that nitrogen would show up , even with the soap test , for pinholes, .............
Where did i go wrong ??????????
Professional Member
what did you pressure it up to with nitro? did you isolate the system? did you use a leak detector? sounds like the system was hacked in at first,lol
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we need a few more sheep dogs to keep barking at the wolves,and the stupid sheep
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Professional Member
Yes i isolated the system by the valves at condenser unit and tested the lines and coil only
Got Low side up to "P" and high side up to 250 Psi.
Yes it was a ........... when i go there.
I would guess that nitro would expose that kind of leak ?
Regular Guest
Valid point on the nitrogen pressure. I know that most reference books call for 150 psig maximum but what would be the maximum you guys would go if you had that problem leak that you just cannot seem to find? On a hack job install that would be risky I guess, especially if they are unskilled with a torch, you might just blow a entire joint or two or three or four LOL
Regular Guest
Is this Res. or Comm.?Low backpressure could also mean the blower is running too slow(or backwards)(take amp draw),a dirty filter or dirty evap if it was running during any construction.(sheetrock dust).Look for any sign of oil,I use up to 130# of nitrogen and listen for hissing.Install a sight glass on the LL ,just befor the condenser,so you can watch it when you add charge. Nitrogen is good but sometimes you need to add a little refrigerant for the leak detector to work.Also ,sometimes you fix the leak when you put your gauges on.Could be bad shrader vales.
Professional Member*
What makes you sure that you did anything wrong? Just because another person, in a long line of service techs that this homeowner has called, said they "found THE leak" don't automatically assume that you missed something or did anything wrong.Originally Posted by derbysr
Give this one a couple of months and then call the customer back to "check up" on how things are going with their air conditioner. You might find out that 3 more companies have also been out since and found more leaks.
Use the biggest hammer you like, pounding a square peg into a round hole does not equal a proper fit.
Professional Member
That is very good advice.
God Speed, Jim. We'll miss you - 2-26-23
Did you pull your hoses off and check the schraders for leaks.
Professional Member
happens too often
we need a few more sheep dogs to keep barking at the wolves,and the stupid sheep
A well-regulated militia, being necessary to the security of a free State, the right of the people to keep and bear arms, shall not be infringed.
Professional Member
maximum pressure.......as much as it can hold.
I also use a set of uniweld guages. The low side guage goes up to like 450 and the high side up to 800 I think.
I have pressure tested systems to 350 and 400 before to find a pinhole or to isolate.
I fully support the military and the War on Terrorism.
If you don't know, then don't do. If you don't know and still do, then be prepared to pay someone else a lot to undo what you did and then do it right.
If you do know, then do. But do it right. Otherwise, you may not be doing it long.
Professional Member
Yes i have the presure up to 350 Psi on other Jobs and you "will" listen to that hising , but for some reason nothingh for this JOB.
My view is :"THE GUAGES NEVER LIE!"
No return.
The data plate on an evap is usually press tested to 150psig. It is not wise to surpass this point.
Has anyone given thought to the fact nito has a heavier (denser) molecular weight than 22?
Professional Member
I use nitrogen with 22 as a tracer gas, which is EPA Ok, and one of my leak detectors usually my Inficon D-tek or my H-10. Use only the best leak detector so you can trust it, and look until you find the leak. On one system I was installing I set up the standing pressure test with nito and 22 tracer, found a small leak at one of the joints with the D-tek, it was late so I packed it in for the day and came back th next day, the gauge was still exactly at the same pressure as when I left, it showed me the benefit of using electronic leak detectors. Once it took me three hours on a Liebert system , the customer instead of being put out at the length of time said he was impressed with my thoroughness and tenacity, that I didn't give up and just charge it up and leave.
I bought my D-tek after studying the posts on this site about leak detectors, it's the best advice you can get, and I've not regretted spending the extra money for the best product
Regular Guest
I've also been tricked by my own gauge set.Added a holding charge,watched the pressure slowly drop,leak check everything again,etc.The system was fine,the leak was the HP stem packing of my gauge set.By the time I was done ,I had the cleanest compressor in town.An old timer told me "Don't believe everything you see!"Your gauges could read Zero but you could have a full charge sitting on the other side of a check valve.You'll find that out when you open up the system .Lieberts are good for that.
Regular Guest
1st tech out, press. test nothing.
2nd tech out press. test nothing told him to add dye
Finally I go out, for sure 400 psi would show leak, nothing, wip out the light YES attempted to show customer the leaks but he said he wasnt sure what h was looking for so i figuered ok now that i know where they are some bubbly would help him see...........friggin things would not show still. Oh well dye didnt just walk there to have a party. Man I need an affordable sniffer any recommendations? My shop wont pay for it so i need to shell out my own cash for it so anything moderatly priced will be good.
Professional Member
First off, Ebay is where I got my leak detector. Got an Inficon Tek-Mate. It works great. The D-Tek is the top of the line. Get it if you can afford it. You won't regret it.
Second, 400psi and no bubbles? Sounds a little off to me. Maybe your extreme pressure is blowing the soap soluation away from the leak as apposed to blowing the bubbles like it should.
And Last, IMO, I don't recommend the dye. I don't like it. I don't use it. It only has a decent chance of working in the dark. It cost too much. And according to a study that Trane did, Dye solution has an adverse affect on the compressor internal components over long periods of time. Don't know how much time, but thats what was taught at the last Trane class I attended.
I fully support the military and the War on Terrorism.
If you don't know, then don't do. If you don't know and still do, then be prepared to pay someone else a lot to undo what you did and then do it right.
If you do know, then do. But do it right. Otherwise, you may not be doing it long.
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