High Pressure Gauge-CO2 Leak

[jplickel]

When I turn off the valve on the CO2 tank and leave the rest of the valves on overnight the high pressure decreases.

Is this due to a leak?

Other posts suggest yes, but when I leak test the high pressure needle doesn't move. I think it is a slow leak based at the coupler.

What could cause the coupler to leak?

I inspected the coupler by taking it apart and all seems to be ok. Used the soapy solution and could not identify anything.

Any suggestions?

[jackstraw]

You're saying the output pressure of the regulator decreases? I have never tried this test before. There could be a number of possible answers. The keg is filled with beer? Depending on what the pressure is set to and what temp the beer is, it could absorb some of the CO2.

Can I ask what prompted you to test this? Do you think you have a gas leak?

[jplickel]

Thanks for your reply.

Yes, I think I have a leak. Yes the keg is full.

The gauge that says the pressure of the CO2 tank decreases (high pressure guage) when I shut off the main valve. Other posts say when this decreases when shut off there is a leak.

Originally, I went thru 1 5# CO2 tank in 1.5 half barrels so I ordered a new double gauge regulator thinking that was the source. Still being cautious, I am shutting off main valve on the tank every night so I don't waste more gas. When I wake up it is down to 0 psi from 500psi. However, the low pressure remains constant at 10 psi. The liquid temperature is about 40 degrees F.

I thought High Pressure was to remain constant as well?

[lunkhead]

Shut off the low pressure side going to the keg too. The keg should keep its pressure. If the high side still leaks down and the low is ok than it sounds like a high pressure leak. Spray all the fittings down with a soapy water solution and look for bubbles. I just had a problem where my high side leaked where the pipe that screws into the regulator body was leaking. Took it apart, cleaned it up, new teflon pipe dope rated to 3000 psi and it leak checked good at 700 psi from my 5 lb bottle (sat 3 days and no leak) Filled up the 20 lb bottle and reconnected and it leaked again from the same place!!! The new bottle pressure was 850 psi. So I bought a new reg from MM and all is well. But I'm going to fix that leak on the other one yet.

[bstelt]

This was EXACTLY my symptom - high guage 0, low guage 12 with CO2 tank turned off.

http://www.micromatic.com/forum/us-en/trouble-shooting-beer-quality-home/2769-co2-leak-mystery.html?highlight=co2+leak

After replacing the regulator, it works fine. I took apart my original regulator but didn't see anything obvious.

[jplickel]

The high and low pressure is now staying constant since decoupling the keg with the main valve in the off position.

With the main valve and the secondary valve in off position the high pressure and low pressure also remained constant.

With the keg coupled and the main valve off is when the high pressure has decreased but low remained constant.

I already replaced the regulator just 1 week ago. Sprayed everything and could not see a leak.

Problem lies somewhere after the secondary valve, I am thinking the coupler. I called Danby and they are sending me a new one. Cross my fingers.

Is my line of thinking right?

[Scott Zuhse]

If your high pressure gauge pointer moves after turning the cylinder wheel off, you have a leak. Try to isolate where it may reside. First, turn the shut off at the regulator to off position and then turn the cylinder wheel off. If the pointer drops, your leak is right at the regulator.

The issue could be the seal between the cylinder and regulator. Possibly the internal seat capsule assembly is loose or defective. Could be a torn diaphragm. Maybe the shutoff itself. Regulator exploded view.

If your pointer holds, turn the regulator shut off to on position and uncouple the keg. Turn cylinder wheel off. If pointer on high pressure gauge drops, your leak is between the shut off and the coupler pressure inlet or the o-rings at the probe are damaged. Coupler exploded view.

It the pointer does hold, the leak may reside at the bottom seal of the coupler. Couple the keg and then turn off the bottle. If the pointer drops, suspect either this seal or the keg valve, although rare, might be the culprit.

Disregard the low pressure gauge.