Yong Heng Leak

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FIDI_G

FIDI_G

Member
Feb 1, 2023
301
160
Atlanta GA
Hey guys,
Could use a little help. I've got several air leaks. Just trying to figure how to deal with it. I'm nervous about the all the aluminum as I know it can strip easy. From what it looks like the main leak is coming from the brass fitting with the tiny disk. It also has a small hole and appears to be venting. Is that normal. I've attached a vid and some pics. Let me know what I can do to address these leaks.

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FIDDI,
That's your burst disc, you'll need to remove collar, replace disc with new, and re-install. The stainless-steel lines are tricky to re-seal after removal. There's a grey sealing ring which has to seat evenly, gently tightening each end, while slightly wiggling steel line until both ends seat together, then complete tightening. Tightening down one side then forcing the other doesn't work. WM
 
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FIDDI,
Search eBay for Yong Heng "burst disc" or "explosion proof valve" to view helpful photos. Might need to also consider replacing steel lines if gray sealing material is damaged, eBay has sets for sale. Don't think it hurts but doubt Teflon tape is helping, small, white "donut" plastic washers, dowty seals (rubber "O" ring/metal washers) and grey sealing material do the sealing. WM
 
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FIDDI,
That's one of the white, plastic "donut" washers I mentioned. You'll also have one inside each opening for the black knobbed pressure-release screws, it's what you tighten down against when you close them. Should have spares in a plastic bag of extra parts, if previous owner provided. I've replaced my leaking ones using a thin wood screw to carefully grab the internal center of the "donut," then remove. Many YH owners keep spares of burst discs, foster-fitting internal "O" rings and Delrin "donut" washers. WM
 
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jps2486 said:
I've been chasing leaks for quite some time. Add more teflon tape and carfully tighten.
Click to expand...

NO!

These are compression fittings, NO Teflon Tape!

Use a small amount of anti-seize on the threads to prevent galling but the seal is the seat, this is not NPT and the threads do not seal.
 
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I have always felt a little air coming out around my hard lines but ignored it until the time to fill my 45 minute SCBA tank went up noticably. Then I decided it was time to take it apart (for the first time) and look things over. So I removed the lines and took the upper part of the compressor apart. I found some soft soot on the high pressure pump I wiped off. I didn't see anything obvious elsewhere but decided to replace the O-ring next to the reed valve and after I got it back together the fill times went down to where they were at first or possibly a little better. I still feel a little air leaking around the lines.

I think it's better to judge leaks by fill time than by feeling air or bubble in soapy water. But if fill time goes up, tightening the fittings on the hard lines is a good idea but replacing the O-ring is a cheap easy step too.
 
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Head gasket fixed. I still have a leak from burst disk.i do feel a lot of airflow from the oil vent. Assuming thats normal. It still won't build enough pressure to fill the gun though. There are stillnsome leaks but cant really figure out where there coming from.

Soapy spray isnt showing bubbles on the fittings but I can still feel a fair bit of airflow just hard to tell if its from the oil vent or somewhere else.
 
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FIDI,
Airflow from oil vent is OK, mine does it, too. Burst discs should arrive quick, I'm in Florida. After a year my YH wouldn't build pressure, tore top half apart searching for leak, just a bad "O" ring in female foster fitting. (Included 6 same "O" rings with burst discs) Don't regret tearing YH apart, learned enough to help others. Made a head gasket from cardboard after mine broke, too. The Delrin "donut" washers I tighten black-knobbed pressure-release screws into started to leak, replaced using thin wood screw trick, with spares that came with YH. Someday I'll order some 10mm Delrin washer spares on eBay. WM
 
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WorriedMan said:
FIDI,
Airflow from oil vent is OK, mine does it, too. Burst discs should arrive quick, I'm in Florida. After a year my YH wouldn't build pressure, tore top half apart searching for leak, just a bad "O" ring in female foster fitting. (Included 6 same "O" rings with burst discs) Don't regret tearing YH apart, learned enough to help others. Made a head gasket from cardboard after mine broke, too. The Delrin "donut" washers I tighten black-knobbed pressure-release screws into started to leak, replaced using thin wood screw trick, with spares that came with YH. Someday I'll order some 10mm Delrin washer spares on eBay. WM
Click to expand...
Thanks for the burst disk and orings. I'm back up and running with a new piston / rod kit with new gaskets and new burst disk has fixed my issue. I was able to fill to about 280bar before I shut er down.

I do have another question though. It gets really hot. I had a five gallon bucket filled with ice and water and got to like 48c in about 5 minutes it was just enough time to fill my. Is this normal. I heard 15min or 52c before you shut it down and cool it. But mine was getting hot quick.
 
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FIDI,
You're welcome, good to hear you're up and running. Three of my PCPs are 300BAR capable, never go over 270BAR, just feel the YH straining, and I like to baby it. 250BAR PCPs, I fill to 260BAR, by morning they've cooled down to 250BAR. Compressor gets hot, you can easily burn yourself on the steel lines, BE CAREFUL, it's all part of compressing air. Your numbers sound normal, I rarely break 50 degrees C when filling guns, I pre-chill water with ice bottles for about 20 minutes before starting an air-fill session, then pre-chill my room temperature compressor by running water pump till digital readout is in 18s-degree C. (Never pre-chill a hot compressor, only a room temperature one.) After turning on external fan, I'm ready to start. I only fill guns and let water pump and external fan run for 45 minutes between gun fills, sometimes I even add fresh ice bottles to 5-gallon bucket when others melt. Most guns fill in 2-3 minutes since I only shoot down to my regulator setting (130-160BAR), never filled a SCBA tank so can't offer any advice. WM
 
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WorriedMan said:
FIDI,
Airflow from oil vent is OK, mine does it, too. Burst discs should arrive quick, I'm in Florida. After a year my YH wouldn't build pressure, tore top half apart searching for leak, just a bad "O" ring in female foster fitting. (Included 6 same "O" rings with burst discs) Don't regret tearing YH apart, learned enough to help others. Made a head gasket from cardboard after mine broke, too. The Delrin "donut" washers I tighten black-knobbed pressure-release screws into started to leak, replaced using thin wood screw trick, with spares that came with YH. Someday I'll order some 10mm Delrin washer spares on eBay. WM
Click to expand...
WorriedMan

Do you happen to have the eBay links for where you purchased your burst disc and what you were considering for the delrin washers? I'd like to buy some spares before I need them.

-PJ
 
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PelletJunkie said:
WorriedMan

Do you happen to have the eBay links for where you purchased your burst disc and what you were considering for the delrin washers? I'd like to buy some spares before I need them.

-PJ
Click to expand...
PJ,
Sorry, links I cannot do, probably the least computer savvy around. Easy to find on eBay, search "Yong Heng Explosion Proof Valves" or "Yong Heng Burst Discs." Scroll down you'll see the 50-pieces pack, $6, free shipping. Smaller assortments are available but same size as burst discs on my M50 filter, so got larger pack. WM
 
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WorriedMan said:
PJ,
Sorry, links I cannot do, probably the least computer savvy around. Easy to find on eBay, search "Yong Heng Explosion Proof Valves" or "Yong Heng Burst Discs." Scroll down you'll see the 50-pieces pack, $6, free shipping. Smaller assortments are available but same size as burst discs on my M50 filter, so got larger pack. WM
Click to expand...
WorriedMan

Thanks, that search criteria worked and I just ordered them. I also tried the "10mm Delrin washer" search in eBay and it pulled up rubber washers instead of the delrin. What search terms did you use for the white delrin washers? I even went as far as to key in "Yong Heng" and scroll through all items but didn't see only the washers, they were part of a rebuild kit with other o-rings, etc.

Cheers,


-PJ
 
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PelletJunkie said:
WorriedMan

Thanks, that search criteria worked and I just ordered them. I also tried the "10mm Delrin washer" search in eBay and it pulled up rubber washers instead of the delrin. What search terms did you use for the white delrin washers? I even went as far as to key in "Yong Heng" and scroll through all items but didn't see only the washers, they were part of a rebuild kit with other o-rings, etc.

Cheers,


-PJ
Click to expand...
PJ,
Silent provided link to Amazon, I couldn't find on eBay either, I've already got some in my Shopping Cart at Amazon. WM
 
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