Yong Heng developed an air leak...

[deadaim]

My Yong Heng compressor has ~9 hours runtime and it has developed an air leak. When it was new, I recall getting a max fill of ~4300psi into SCBA 45min tank. Lately it has been around 4000psi before the auto-shut off triggers. Today, I felt air blowing from this fitting (circled in red), I tried tightening it and it still leaks. I believe it is leaking from where the pipe goes into the coupling.

1. Has anyone else had this issue?
2. Can it be fixed by disassembly/reassembly and teflon tape or are new parts required?

Thanks in advance!

 

[Firewalker]

A little heads-up on JIC flare fittings, straight tightening will get you a cracked line, this is stainless steel and it's dry, it binds and galls like mad! Back it all the way off, check the fitting going into the second stage, make sure that is tight, use a drop of your case oil on your fingers, just s film will do, rub it on the flare and tighten like a see-saw.

A little tightening, break it almost loose, tighten up a little more turn it back just a smidge, repeat until tight then test.

Good luck!

 

[airgunner1042]

Unless the threads are galled, teflon tape should do the trick

 

[Camaro454]

It appears this is a compression fitting, however, if you remove the nut is the tube end flared or is there a compression ferrule on it? If compression and leaking out top of nut around the tube entry you may have overtightened. If leaking between nut and male fitting thread then Teflon tape could help.



Here is a picture of compression fittings on a tube.

 

[WorriedMan]

Deadaim,
Camaro's picture shows grey compression ferrule you should have on yours, reminds me of a lead ring but I'm sure it's a composite material. After pulling steel lines to remove high pressure head for inspection, I found re-installing easiest using methods similar to Firewalker's suggestions. Finger-tighten both ends as much as possible, keeping tube loose, then slowly tighten back and forth, evenly, between ends, moving steel tube gently until you feel both ends seat, complete tightening. Cranking one side down then trying to seal the other doesn't work. If sealing problems persist, don't be afraid to pull line off, inspect both ends, especially for cracked composite material, if OK, then re-install, as suggested. I'd just replace steel lines, from eBay, if any problems were found. WM

 

[deadaim]

Thanks for all the wise guidance. From everything I have heard, I should never over tighten any part of the Yong Heng. I did not notice any teflon tape on this fitting. Glad to know it is OK to use it airgunner1042 . It was hot after topping off 3 tanks so I'll disassemble it when I get the time. I'll let you all know what I find.

 

[Firewalker]

Unless the threads are galled, teflon tape should do the trick

Thanks for all the wise guidance. From everything I have heard, I should never over tighten any part of the Yong Heng. I did not notice any teflon tape on this fitting. Glad to know it is OK to use it airgunner1042 . It was hot after topping off 3 tanks so I'll disassemble it when I get the time. I'll let you all know what I find.

I disagree with the Teflon tape, it has no place with compression or flare fittings and can exacerbate the issue.

For strictly thread-to-thread sealing such as pipe fittings, it's fine but don't wrap the flare.

 

[flashdad]

I have a new Yong Heng that I have gotten around to use yet. Would teflon tape be a good preventive measure on the threads?

 

[charlie99]

This is the exact place where I had air leaking about a week ago. It turned out that air was actually coming from the bonded washer. I replaced the washer with one provided with the compressor and all is well again. Looking at the washers as I'm typing this, it seems that the high temperature has caused deterioration of the rubber material on the bonded washer. I'm referring to the washer in the first picture that's connected to the aluminum part of the compressor. That what was wrong with mine.

 

[Franklink]

This is the exact place where I had air leaking about a week ago. It turned out that air was actually coming from the bonded washer. I replaced the washer with one provided with the compressor and all is well again. Looking at the washers as I'm typing this, it seems that the high temperature has caused deterioration of the rubber material on the bonded washer. I'm referring to the washer in the first picture that's connected to the aluminum part of the compressor. That what was wrong with mine.

What was your max temp prior to needing to replace this dowty?

 

[charlie99]

The temperature probe that came with it never went over 55. Those stainless steel pipes get HOT. I accidently touched it with my forearm last summer and i still have a burn mark there. Touched it for half a second.

 

[WorriedMan]

The temperature probe that came with it never went over 55. Those stainless steel pipes get HOT. I accidently touched it with my forearm last summer and i still have a burn mark there. Touched it for half a second.

I wear those scars as a mark of pride, prefer not getting them, though. WM

 

[WorriedMan]

I have a new Yong Heng that I have gotten around to use yet. Would teflon tape be a good preventive measure on the threads?

I'd recommend against, steel lines are easy to mess up removing and installing, that "preventative" measure might cause more harm than good. WM

 

[Firewalker]

I have a new Yong Heng that I have gotten around to use yet. Would teflon tape be a good preventive measure on the threads?

Not in my opinion, a very very small amount of anti-seize on the threads is a much better answer than introducing a foreign object onto the flare causing a leak. The flare is engineered to be used in concert with the nut which has the opposite flair, those together keep the air seal, not the threads, those are just the mechanical tightening device.

 

[Firewalker]

I have all the tubes if you need them. PM me if you are interested.

 

[deadaim]

I took the leaking tube apart today, it came off easily. The ferrule creates the seal against the SS tube, I get it. Don't have time to reassemble and test the compressor tonight, UFC fight is calling my name. Let you know what happens when I get around to it. Thanks again for all the help.

 

[JimD]

When the fills of my 45 minute SCBA tank started taking longer I took the disassembly further than you have so far. I felt air around the lines too. There is an O-ring beside the reed valve that I replaced and my fill times went back down to what they were before. I still feel a little air around the lines however. So maybe it isn't perfect but I can fill my tank from about 3200 to about 300 bar in under 15 minutes now so I think it is plenty good enough.

 

[deadaim]

Sorry for the delayed update but I have 3 SBCA tanks and I wait until all tanks are below 3000 psi before another refill session. Here is what happened, I removed the leaking tube and re-installed it with a flare nut wrench. It is cranked down tight, however there is still leaking. As you can see I struggled to get my tanks filled to 4000 max. I just ordered a set of 3 new tubes from Aliexpress. I will report back when I get the new parts installed. Thanks for your support.

 

[deadaim]

After more investigation and getting 3 new stainless lines, it turns out that the was really coming from the threaded fitting. Like
charlie99 mentioned! Thankfully, the compressor comes with extra washers so I replaced the deteriorated washers and I'm up and running. I did not have a water spray bottle handy so I used foaming hand soap to test for leaks. I topped off my 3 tanks and it is running well. Thank you for all your support.

 

[Dog]

I hate soapy water on my fittings particularly on my air rifles snooping for leaks. Yeah, cheap and easy right? I use cheap silicon oil as the oil that seeps into the blued spaces between o'rings does not cause corrosion. I don't like getting the steel cap head bolts on the YH water wet for same reasons. I'm weird like that..