After 6 or so years of no issues, I finally have a gas leak somewhere in my system. I think I have it pinned down to the high pressure portion of my regulator, but I'm wondering if you guys can let me know if my thought process is correct.
What I did was turn the gas on so that the high pressure gauge read about 500 and the low pressure gauge read about 14. I then closed the valve that leads from the regulator to the gas manifold and turned off the gas. When I checked it a few hours later, the high pressure gauge read 0, but the low pressure gauge still read 14, and there was still pressure that could be released through the pressure release valve (which then brought the reading on the low pressure gauge to 0). I repeated this process twice and obtained the same result.
My thinking is that this means the leak is in the high pressure portion of the regulator, so it's either the connection between the reg stem and tank, the connection between the reg stem and body of the reg, or the connection between the high pressure gauge and body of the reg.
I believe my experiment shows that the low pressure part of the reg (pressure relief valve, low pressure gauge connection, pressure control knob, and valve leading to the manifold) are not leaking.
Does that seem logical? I'll try to verify the source tonight using soapy water.
I've tested all the other parts of the system, and this seems to be the only one that won't hold pressure overnight once the gas has been turned off.