YH QB01 no pressure and leaking past decompression valve?

[jason R10]

My poor old compressor (although hasn't done much work) has been in the summer house for 2+ years although in decent storage box, when i came to use it it was seized and wouldn't turn over.

I took the HP head off to inspect and found it pretty gunked up. I got some replacement gaskets (base and bottom) which came with a new HP piston so fitted them.

Now the Comp seems to run nicely and without leaks but i just found the burst disc burst so replaced that.

Problem is There is air coming out of the right hand side decompression valve when screwed in as if filling. I cant remember if with the knob tightened should seal that and stop air from passing completely? before connected up to the dive bottle?

Main issue is i am getting no pressure on the gauge needle. The small shim that sits on the HP barrel next to the green o-ring, does that have to sit in a particular position?

Where should i look further? should I look at replacing the bottle feed/pressure gauge/burst disc block?

TIA

 

[WorriedMan]

Jason,
Pressure-release valves on the Yong Heng seal as the rounded tip pushes against the open center of a white, plastic Delrin washer. Spare Delrin washers should be in YH Spare Parts bag, looks like miniature glazed donut. Best way to test for YH leaks is a dead-head plug (pictured) and a soapy water spray bottle. Pressure up system, shut off, spray check for leaks, release pressure. (Never re-start under pressure.) WM

 

[jason R10]

Thanks and any tips to get one of the delrin washers out?

the dead head comes from aliexpress?

 

[jason R10]

Ah yes, i see its a quick connect blank. I have one so out with the soapy spray

 

[WorriedMan]

Thanks and any tips to get one of the delrin washers out?

the dead head comes from aliexpress

Remove brass fitting, twist proper size screw into Delrin washer center and extract. Some mashed Delrin washers take more effort as in gently splitting with blade and removing with needle nose pliers. Be mindful of fragile threads brass fitting uses. WM

 

[WorriedMan]

Ah yes, i see its a quick connect blank. I have one so out with the soapy spray

Check all connections, I foolishly removed HP head searching for problem, all the while a bad "O" ring in female foster was culprit. Gauges are notorious for failing, too.

 

[Gerry52]

Pictures always help tremendously in situations like this. Someone's description of the parts & problems might not be interpreted the way the "describer" meant them to be. Pictures reduce that possibility. I believe you meant the HP bleeder screw (black knob) on the right side of the compressor. If it's leaking air it's most likely the white delrin insert needs replacing (mentioned above by WorriedMan). If I'm misunderstanding please enlighten me.

 

[Gerry52]

Remove brass fitting, twist proper size screw into Delrin washer center and extract. Some mashed Delrin washers take more effort as in gently splitting with blade and removing with needle nose pliers. Be mindful of fragile threads brass fitting uses. WM

I've found if you heat the head of a small slotted screwdriver & melt a "slot" in the center of the delrin & let it cool, it's easy to "unscrew" the damaged disc out causing no damage to threading by having to cut it or dig it out.
Gerry

 

[jason R10]

Pictures always help tremendously in situations like this. Someone's description of the parts & problems might not be interpreted the way the "describer" meant them to be. Pictures reduce that possibility. I believe you meant the HP bleeder screw (black knob) on the right side of the compressor. If it's leaking air it's most likely the white delrin insert needs replacing (mentioned above by WorriedMan). If I'm misunderstanding please enlighten me.

Its leaking air through the outlet (as to dive bottle) even thought the black screw knob is closed tight. ill get some picture tomorrow as i have other questions about parts.

 

[jason R10]

So air is coming out of the EX port with the DV (Decompression Valve) port closed is one question, I cant remember if it seals completely?

This check valve came apart like this. should it have an O-ring? If so i have no idea where its gone.

The burst disc on the left, Is that an example of a burst burst disc? the fresh one on the right is already starting to deform.

 

[jason R10]

ok blanked off EX port to try and get pressure up for a leak test. the compressor is only just moving the pressure gauge needle and i get a whining noise after shut down as in vid. sounds pretty terminal. I think ive screwed up because the reed valve on the high pressure cylinder was not in the right position as when it came apart. As it stands it is now .

 

[WorriedMan]

EX port is outlet where fill whip (hose) seals to compressor with Delrin washer. DV (Decompression Valve) is pressure-release, which vents downward thru hole in block, when black knobbed screw is opened. As discussed previously, black-knobbed screw seals against center of Delrin washer. Start compressor with both black-knobbed screws open, then close to build pressure. Air exits at outlet port, enters fill whip (hose) and proceeds to filter, airgun or tank, when pressure-release black-knobbed screw is closed. Dead head adapter pressure test is designed to insert in female end of fill whip, properly Delrin washer-sealed to compressor at EX (Outlet)port. Recommend pressure testing in this manner, soapy water spray test to determine location of leaks. Check valve, burst disc and reed valve might be fine, importance of leak location is priority. WM

 

[WorriedMan]

Might want to head over to YouTube and watch Sambo Cotton's or Air Velocity Sport's Yong Heng rebuild videos, for answers. WM

 

[jason R10]

DV Delrin washer replaced. EX port blocked off.

Yes i understand this. I am still getting air from the EX port with the DV closed.

 

[jason R10]

Might want to head over to YouTube and watch Sambo Cotton's or Air Velocity Sport's Yong Heng rebuild videos, for answers. WM

yes i will take a look thanks

 

[Gerry52]

You SHOULD be getting air through it ("EX" port)! That's how it gets to your bottle, tank, gun, whatever. The bleeder valve below it is only for bleeding pressure in compressor & fill line, NOT for closing off what comes through EX port! It's a bleed screw, NOT a shut off screw.

 

[jason R10]

You SHOULD be getting air through it ("EX" port)! That's how it gets to your bottle, tank, gun, whatever. The bleeder valve below it is only for bleeding pressure in compressor & fill line, NOT for closing off what comes through EX port! It's a bleed screw, NOT a shut off screw.

Thanks that's what i was after.

Next question is my QC's have a 1/8 BSP thread. The whipline and filter that comes with the compressor don't seem to match up as in a very tight fit.

Does anyone know this thread size?

I have just discovered my compressor is an Orion manufactured one. not sure if this makes a difference.

if the HP block check valve pictured above should have an o ring, which one is it?

 

[Gerry52]

IF your bsp threading is not lining up it could be npt threading that's required. Unfortunately there's no standardized fittings on a lot of stuff especially if they're China knock offs. ORION seems to be a knock-off of original Yongiheng manufacturer. Can't answer your question about WHICH o-ring or even if it's required because WHO KNOWS what knock-off companies are doing! Sorry! Try it both ways. WITH & WITHOUT a ring. It looks to me like the brass part of valve already has a rubber seal on it.

 

[WorriedMan]

Thanks that's what i was after.

Next question is my QC's have a 1/8 BSP thread. The whipline and filter that comes with the compressor don't seem to match up as in a very tight fit.

Does anyone know this thread size?

I have just discovered my compressor is an Orion manufactured one. not sure if this makes a difference.

if the HP block check valve pictured above should have an o ring, which one is it?

Metric 10mm is thread size for compressor, fill whip and filter.

 

[WorriedMan]

Thanks that's what i was after.

Next question is my QC's have a 1/8 BSP thread. The whipline and filter that comes with the compressor don't seem to match up as in a very tight fit.

Does anyone know this thread size?

I have just discovered my compressor is an Orion manufactured one. not sure if this makes a difference.

if the HP block check valve pictured above should have an o ring, which one is it?

Sambo Cotton deals with check valve in video, best to check it out.