Gas Leak

[Galena]

So I lost a full bottle of CO2 left turned on and connected to 3 cornies.
I regularly check for leaks by spraying with Starsan to all John Guest fittings, connections, cornie seals, regulator connections etc and have never seen so much as a bubble, and yet leak it did.

So with a new full bottle I am too paranoid to leave it tuned on and am wondering if I have a leak by the issue in the attached picture.

The two regulated valves stay constant, maybe drop a little on a newly kegged beer as I would expect, it is the bottle pressure valve that drops down to zero everytimes.
Occasionally within a short time, occasionally a few hours but drop it does.

My question is, what part of the system might the leak be if only the main cylinder gauge is dropping?

 

[Larse]

Trial and error might be the best way forward. Start disconnecting things. I'd start with the second regulator. Turn that off and if no change, then by elimination it must be the first one. Also check all the regulator fittings including the bottle connection and especially the nylon washer. They're supposed to be changed every time the bottle is replaced (I doubt anyone does this, but maybe every few months).

 

[Galena]

Trial and error might be the best way forward. Start disconnecting things. I'd start with the second regulator. Turn that off and if no change, then by elimination it must be the first one. Also check all the regulator fittings including the bottle connection and especially the nylon washer. They're supposed to be changed every time the bottle is replaced (I doubt anyone does this, but maybe every few months).

Thanks, logical idea I'll start with that.

 

[Larse]

Just to answer your question as I hadn't noticed it earlier. The regulated pressure will stay the same until the bottle is empty. If there's a leak anywhere, this won't change as the regulator will keep feeding pressure to the set amount into the lines whether it's leaking or not. So the main pressure will drop because the bottle is being emptied as the regulator(s) try to keep up with demand from the (leaking) system.

 

[Galena]

Just to answer your question as I hadn't noticed it earlier. The regulated pressure will stay the same until the bottle is empty. If there's a leak anywhere, this won't change as the regulator will keep feeding pressure to the set amount into the lines whether it's leaking or not. So the main pressure will drop because the bottle is being emptied as the regulator(s) try to keep up with demand from the (leaking) system.

But if the cylinder valve is closed and the gauge drops to empty, but the 2 regulator valves still show pressure?

 

[Larse]

But if the cylinder valve is closed and the gauge drops to empty, but the 2 regulator valves still show pressure?

There will still be pressure in the system. The pressure in the kegs will be pushing back on the regulator.

 

[peebee]

But if the cylinder valve is closed and the gauge drops to empty, but the 2 regulator valves still show pressure?

As @Larse says. Occasionally, the difference in pressure 'tween the empty cylinder and "bus line" ("back-pressure") will fail to keep the bus-line sealed; but the regulator isn't working as intended (cylinder is empty), and these regulators aren't precision devices, then the bus-line may drop to zero. But in your system (effectively two "primary" regulators in parallel) you'd probably see only one bus-line drop to zero ... that'd be confusing!

It happened to me several years ago. I blamed the seal of the regulator nut to cylinder. I went down-beaten back to the gas supplier from where I picked it up the day before and they gave me a new cylinder! I was told it happens sometimes ... the cylinder doesn't fill properly, and they don't pick it up on weighing the cylinder. I can't say you'd be so lucky! But losing that much gas overnight is going to make a very audible hiss ... never mind blow bubbles!

I've since ensured the gas is turned off after every session. It's on a timer (solenoid valve) along with solenoid valves opening beer-lines so I can't draw beer without the gas being on. Paranoia? But that would be difficult to setup with your system ... you've two bus-lines and the regulators having no means of integrating a solenoid valve in the regulators. It only protects from faults in the bus line, not 'tween cylinder and regulator. Humm ... the cylinder loss happened five years ago ... I remember now, because I've only had one refill since (when I bought the second cylinder as insurance too ... the first "Covid" relaxation).