Help troubleshoot my gas system

[bstacy1974]

I'm having an issue with my CO2 system lately. Since upgrading to a larger tank I've had to refill it four times in three months. Most of those refills I can explain but now I've come to a situation that I don't understand. The high pressure side of my regulator well go to zero if I shut the tank valve, while the low pressure side of the regulator will stay at 10 psi.
I've replaced all of my tubing, clamps and fittings. The only thing left is a regulator leak. Has anyone experienced this situation?

 

[day_trippr]

If the high pressure side dives to zero, there's a hella big leak somewhere. What happens if you shut off the output valve?
I would start by removing the regulator and checking to see if there's a viable gasket inside the regulator coupler nut...

Cheers!

 

[bstacy1974]

I have a gasket between the regulator and tank. When you say output valve, which side? Main tank output or regulator output?
The tank has been in use for about a month. I noticed the pressure was lower than I expected. So I shut off the tank valve yesterday. When I got a beer tonight the high pressure gauge was at zero but the low pressure was at 10.
When I open the tank valve, high pressure gauge goes up. Close the valve, it immediately drops.

 

[Joeywhat]

Put your hand tight over the tank valve with it open and let it sit for a second. Push it on there real tight to get a good seal. Does it make a sound when you let go? If it does it sounds like the tank valve is leaking.

 

[day_trippr]

^That^ would not address the issue, presuming the regulator coupler seals tight. Indeed, if the cylinder valve had a leaking stem packing such that pressure was leaking through the output, the OP would not likely see the high pressure gauge drop to zero with the cylinder valve allegedly closed.

It's similar to a leaky gas poppet with a gas QD attached. There may be a latent issue, but as long as the QD seals to the post, no gas is actually lost.

I have a gasket between the regulator and tank.

Good! Are you securely tightening the coupler nut? If you can spin the regulator, tighten the coupler more

When you say output valve, which side? Main tank output or regulator output?

That would be the low pressure side - most regulators have a "shut-off" valve on their output.

The tank has been in use for about a month. I noticed the pressure was lower than I expected. So I shut off the tank valve yesterday. When I got a beer tonight the high pressure gauge was at zero but the low pressure was at 10.When I open the tank valve, high pressure gauge goes up. Close the valve, it immediately drops.

Yeah, something is hugely wrong if the high pressure side drops immediately. I mean, to the point you should be able to at least hear where the leak is - either at the cylinder coupler or some part of the regulator assembly...

Cheers!

 

[bstacy1974]

Gotcha. I'll give it a try tomorrow.
I played around with it a little more. I closed the outlet valve of the regulator. Made an adjustment to lower the outlet pressure, then opened the tank valve. The high pressure gauge went up, I closed the tank valve, and the pressure held.
I did this a few more times, bleeding off the pressure each time. The pressure is holding.
I closed all the valves but left pressure on the regulator. I'll see if it holds overnight.

 

[day_trippr]

fwiw, I have had regulators that had leaks around things like low pressure gauge stems and even a PRV valve stem (that one was uber slow and a pita to find). BUT, none of them dropped the high pressure rail quickly - these took many days to bleed out.

I have 5 primary CO2 regulators in service between a keezer and three brewery fridges and the worst of them takes about a week to bleed the high pressure rail to zero after a shut-off. I've been planning on taking a look at that.

The thing is folks tend to treat these gas systems as something mystical, but at the end of the day, if all of the seals, O-rings, gaskets and diaphragms are working properly, a system should only give up gas to actual "work" - like carbonation or dispensing. And a closed system should never evidently leak...

Cheers!

 

[bstacy1974]

I ended up buying a new regulator rather than continue to chase issues.
Quick question. The new regulator has an oring on the stem that connects to the tank. Do I still need to use a plastic washer when I connect?
I'm getting a new tank of gas today and want to make sure it doesn't empty while on a trip this weekend.

 

[Brewski_59]

I ended up buying a new regulator rather than continue to chase issues.
Quick question. The new regulator has an oring on the stem that connects to the tank. Do I still need to use a plastic washer when I connect?
I'm getting a new tank of gas today and want to make sure it doesn't empty while on a trip this weekend.
View attachment 726408

No I think this is meant to be washerless

 

[tracer bullet]

No I think this is meant to be washerless

Agreed, the o-ring replaces the washer. Same idea, slightly different method.

I would suggest finding more o-rings. You don't have to replace them all to often but once in a while will be a good idea.

 

[Brewski_59]

Agreed, the o-ring replaces the washer. Same idea, slightly different method.

I would suggest finding more o-rings. You don't have to replace them all to often but once in a while will be a good idea.

In addition to having spares, lubrication is important for O ring life. If you have some keglube, It wouldn't be a bad idea to use a little film on the surface of the O ring prior to installing on the tank

 

[bstacy1974]

In addition to having spares, lubrication is important for O ring life. If you have some keglube, It wouldn't be a bad idea to use a little film on the surface of the O ring prior to installing on the tank

Yes. Thank you. I've solved many problems as a water plant operator with just a little oring grease! I lube every oring I find.

 

[bracconiere]

personally, i use a tank washer anyway....

 

[tracer bullet]

personally, i use a tank washer anyway....

I wouldn't do both. The O-ring may not compress it enough. I'd do one or the other. More isn't always better.

 

[bracconiere]

I wouldn't do both. The O-ring may not compress it enough. I'd do one or the other. More isn't always better.

seems to work for me and my tap-rite, with o-ring. i've found with steel tanks they have a huge groove right where the o-ring is supposed to make a seal. so i need the washer.

 

[jerrylotto]

Your tank might be compatible with a perma-seal. Otherwise, the grooved tank outlets are supposed to have an O-ring - 3/8 x 9/16 x 3/32 is a common size. If you exchange tanks where you refill, check that the o-ring isn't missing before you take the new tank.