Beer Forum

I have a kegerator with a dual body co2 regulator. One unit with two regulators and set points. I've disconnected all kegs from the system. I set one regulator to 30 psi, I set the other to 10 psi. The 30 psi line is just a single piece of tubing with an inline disconnect (mcmaster 5923k43/5923k73) connected to a corny gas qd. The 10 psi line goes to a 4 way manifold and 4 co2 lines with standard corney gas quick disconnects.

After all of the tubing equalizes I turn off the co2 at the tank. Everything holds as expected for several hours. By morning the gauges read a higher pressure than the initial set point. The valve that displays the tank pressure shows a lower pressure by this point. Within a day or two the high pressure gauge shows 0 the other two gauges show lower than expected (10 and 30 psi) pressures. These pressures will drop for a day or two and then level off. When they do level off the pressures will not change.

There is some pressure on the high pressure side of the regulator even after the tank is turned off. I can see differences in temperature drawing this out over time. The tubing gets colder than the point I set it at, gas contracts and additional co2 is allowed to escape into the low pressure side of the regulators. That part makes some sense to me.

What does not make sense is the later drop and subsequent leveling off. Is there a leak that is not apparent at lower pressures? Do temperature fluctuations allow co2 to feedback into the high pressure side of the regulator? Or is this just a completely flawed method for attempting to detect co2 leaks?

stadelman wrote:Or is this just a completely flawed method for attempting to detect co2 leaks?

Perhaps.... to be honest, I couldn't follow your description of your testing procedure. I need pretty pictures.

Crank the system up to 30-40 PSI and get to it with the starsan. You'll find it, if it exists.


Mylo

A simpler explanation of what I'm talking about...

Pressurize everything and then turn off the tank. Use the regulator's pressure gauges to see if there is a leak.

My theory about why pressure rises on the low pressure side of the regulator is false. Low side pressure rises as the high pressure side is emptied. It doesn't have anything to do with expansion and contraction of the tubing as I suggested.

Not sure why it does this.

I don't think regulators operate as perfectly as one might assume. If used normally, they work pretty good. Start turning off the gas, and wierd things happen. Don't ask what your regulator can do for you, ask what you can do for your regulator.

I think this had to do with the fact that I was draining the high pressure side of the regulator. My thinking on this was- this will give me faster results.

I think that without pressure on the high side the regulator allows backflow from the low side to the high side. Eventually all of the dials equalize. This makes it seem like the low side may be leaking.

So, I believe this is a valid method for testing for leaks, but it's essential that the high side pressure be left intact. The tank can (and should) be off, but the little bit of high side pressure needs to remain. Without this pressure the regulator does indeed start to act weird.

Performing this test with high side pressure yielded expected results. Pressures remain stable.