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- เผยแพร่เมื่อ 12 ก.ย. 2024
- Working on a York YCIV chiller that was having a stress leak. It was a very difficult leak to find and we almost missed the worst one. How you can find a refrigerant leak. This is for HVAC Technician who work as chiller techs on air cooled chillers.
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It’s crazy you mention nylog on NPT fittings. This literally happened to me on a suction transducer that i had to replace with an NPT adapter fitting. It held below 200psi (compressor kept failing on inverter fail and let the pressure build past 200psi) but started pissing refrigerant above 160psi. I had to removed the nylog and use teflon tape to create a good seal and stop a leak from forming. And the nuttier part is that the rack was started up a few days ago and had i left and not followed my gut by taking one last peek at the rack, I would’ve completely blown the charge on that rack. Maybe i was just lucky lol
Sealers are recommended from factory manual on York yvaa equipment when it comes to threads on EEV and pop off valves
snoops leak detection fluid. Trutech carries the gallon jugs. It’s the best.
Snoop is amazing
I need to give that stuff a try, I’ve been fighting finding leaks lately even with a leak detector and bubbles.
Man that’s quite the service call. 134a leaks are sometimes the hardest to find especially when it’s in the oil section.
Pressure relief
why not put the system under max pressure (respecting LD/HD limits) with forming gas and go to town with a suitable detector? it would be a lot less time wasted and the leak hit rate would be basically 100% due to the high sensitivity and lack of false positives.
Heat. Things do funny things when hot
Back in the early 80s. I was hired at the local Chevy dealership to do just AC work. Car came in dust. System was dry. Spent 4 hours leak checking then charged it. Worked great. Came back next morning. Dust. Dry as a bone. I was busy so another tech worked on it for another half a day. Same thing. Next day. Dust dry. So shop foreman was unhappy he took the project this time. Spent whole day 6:00 everyone is headed out the door all of the sudden a white cloud over in the corner the hose crimp dumped the whole charge to nothing it was 100 degrees that day so that being said it can be very hard to find leaks. The car was less then 2 years old at the time I do light commercial refrigeration now. Had other funny things happen but expansion and contraction can do funny things. Job well done guys😊
It’s not necessarily the high pressure that brought out the leak, but heat too. Heat expands metal. Same in reverse. On a low pressure chiller that runs in a vacuum, you either heat up the water to bring the refrigerant pressure positive, or pull the charge and put nitrogen on it. Sometimes when you heat up the chiller, the heat seals the leak and you can’t find it.
And also vibration
554 loctite is the best
100 psi N2 test is too low . I will always test 1.5 times past the highest operating pressure as a minimum .
If you have time you should show the process of Loading the machine up full capacity.
I am also a big fan of 554. Very good stuff
Dawn and water finds all them leaks.
Relief Valves ?
Do you have a special tool to replace the seats of the ets valves? We use a modified pipe wrench...
I’m having a similar problem on a 60ton system. Pulled vacuum and recharged still can’t find the leak.
How long do you guys perform a standing vacuum test
depends on the system. Minimum 2hr in a critical scenario. Standard is 4hr on air cooled. Centrifugal are 12hr.
What if the feed valve only leaks in certain positions, eg. 1/4 open, 3/4 open etc ?