New Yong Heng Compressor Air Leaks

Could use a some thoughts to find air leak/s on my brand new Yong Heng.

Water pump working with plenty of water. Checked all fittings were snug.

I have a small 77ci tank for my marauder but it leaked at the gauge. I put some heavy duty teflon tape on it and tried to fill the tank. It would only fill to 500 psi but no leaks at the gauge. I switched over to the my friends Air Venturi Avenger .25 cal and same thing.

I can hear what sounds like air escaping but it's hard to hear with the compressor running. I used soapy water and found a leak at the pressure gauge. Used tape and it pumped up to 1000 psi but that's it. I used a stethoscope to hear better and it helped and still sounds like its from the gauge. But I need something better.

Is their a way to pressurize the compressor maybe with a high pressure hand pump? I would need to know the threads on the pressure gauge. If they are available I would like to use a high pressure hose with male threads like the gauge and then a male foster fitting to connect the pump. Anyone try that.

Looking for a better solution if anyone has one.

I'll order another YH pressure gauge in the mean time.
 
Airslave,

Check to see if one of these came with compressor. It's a tester, insert in end of fill hose, pressurize system, shut down and check for leaks. WM
IMG_20220303_095316.1646319386.jpg



 
Airslave,

The gauge is a weak point of the Yong Heng and it's never a bad idea to have a spare. Not that expensive or rare, so no big deal. In your shoes, if the gauge is leaking and can't be fixed, I'd try the gauge from the broken Vevor or even from a Chinese HPA handpump. It's all from China anyway, so who knows, might just work. Never force anything, though, and try to eyeball that they are similar. I'm not sure how the gauge is sealed to the compressor, might just be a small, white plastic "donut" seal at hole bottom, you'll have to investigate to see if the actual gauge is bad or how it is attached. WM
 
The gauge had some sort of tape on the threads and all of it was outside the threads. Kinda like wrapping it the wrong way????

The Vevor is digital so no go there.

I have some round white seals. I could give it a try. Good idea...

Let you know about the gauge. Appreciate that.

I was hoping the plugging it would work. That would be great if it holds air long enough.

I have a bad feeling about this and I hope I'm wrong.

Thanks for all the info! 

I don't know.... who was it that said that????? :) Now that's funny right thar......
 
Airslave, 

My Yong Heng gauge has no tape, just bare threads into aluminum block. I'm not going to press my luck and remove it, but pretty sure it tightens against a white plastic washer. My $50 Chinese HPA hand pump's gauge tightens against a white plastic washer, too. The strangely wrapped tape on your YH gauge threads has me wondering what is going on. Some members, with YH gauge problems, have just sealed the gauge hole with a bolt and used tank/gun gauge for filling. OK, if you have the correct size bolt. 

If, after removing gauge, you look down hole and don't see a white plastic washer, I'd try one, maybe even try to replace one, with new, if one is already there. Check threads in aluminum block and on gauge for any problems, someone had a reason to use that thread tape. WM
 
Yes as Worriedman and Gerry752 said the white plastic washer seals the bottom of the gauge on the YH. The teflon tape does not belong there.

The burst disc fails as heavy-impact states or blows a small hole in the disc.

https://www.aliexpress.com/item/4000125130013.html

The plastic safety valve on the low pressure block is spring loaded and should return to it's original seal once pressure has been relieved.
 
Wow. great response and I really do appreciate it.

Note::::: I bought this from a link suggested - best-homepro Co, shipped from GA.

1. No plastic washer. It had black almost plastic like tape on it. I replaced the tape. When I tested it on the hand pump it held fine but I'll try the white plastic washer.

Their is a white plastic washer. I removed the tape and reinstalled gauge. OOPS-- Missed it.. my bad.

2. If the burst disk is blown, will the compressor have any output pressure?

Burst disk is ok. Put it back in.

3. Didn't look into the bag of parts but I'll see if the burst disk and white washer are there.

Extra burst disks in in bag but no plastic washer/s that size. Their are 2 that have smaller holes. looks the same as for the YH filter.

4. The dead end didn't provide any information and it didn't show any indications of pressure.

5. Manual says the popoff valve is the 1st safety valve. No mention of another one.

Checked popoff valve. Was a little loose so tightened it. It does spring back when pulled slightly.

Lets see if I'm doing this right.

1. Check oil level.

2. Setup water pump and turn on.

3. Open drain screw and close output valve screw.

4. Connect foster fitting to Air rifle.

5. Turn on compressor

6. Close drain valve screw.

7. When finished open both drain and output valve screws.

8. Shut off compressor.

9. Leave water pump on until head cools. NOTE::: I noticed the head cools faster than the lines do like head is cool but the lines are still very warm.



I like a challange but 2 compressor failures first day is getting me down. Hope I can get up and running.

Again, thank you all for helping. I'll see this through... somehow.
 
Doesn't sound new with a blown burst disc and teflon tape on the gauge

1- Plastic washer for the pump gauge probly teflon tape on the gun gauge.

2- Little to no pressure on the output of the compressor if the burst disc is blown.

3- Both open both closed doesn't seem to make a difference so long as there is no pressure in the unit when you start it.

4- Yes

5- Yes

6- Yes, if it isn't already closed

7- Open the drain valves for a couple of seconds every five minutes during use to purge the moisture.

8- Yes

9- yes it's OK for the cooling lines, stainless ones to be hot.



Here is some Yong Heng help for you.

 Yong Heng post link

https://www.airgunnation.com/topic/a-dedicated-yong-heng-subforum/#post-1127767


 
1. The YH does not use tapered threads and thus doesn't use sealing tape. Are you sure that your pump is a YH?

2. If the burst disk is ruptured, it won't build pressure but this is very unlikely if the unit has never been fully pressurized. 

If it is a YH, the gauge threads are M10x1. Try blocking the gauge hole with a suitable bolt. Don't overtighten anything that has aluminum threads. Don't overtighten the bleed screws. The seats are the same nylon material as the sealing washer and will be ruined if cranked on.

3. If it is a YH, it will have the spare washers or burst disks in the parts bag.

Pressurize the pump to whatever it will make and turn it off. Use soapy water to identify the leak source. Address that thing. Don't pull apart anything that doesn't leak. 

The rest is irrelevant to your problem.
 
1. Someone put a name plate picture of a genuine YH and mine is the same. Might not mean anything but better than Ding Dong.

2. Burst disk is not blown. Sorry for the confusion. I'm going to replace the burst disk. It doesn't look bad but I'll change it anyway.

3. Yep. 

It doesn't seem to be putting out any pressure. I have a couple of tests to run tomorrow to see if I can find anything.

I used soapy water at first and everything was solid. Now without pressure it's kind of hard to do that.

At first it would pump up to 500psi but now nothing.

Thanks you for the input...