Another CO2 leak thread

[IowaStateFan]

BLUF: Bought a new regulator after trying everything else to determine where the leak is. Hooked it up, pressurized the line to 15psi and turned off the CO2. When I checked this morning the high pressure gauge read zero while the low pressure gauge had increased to 20psi. Two questions: 1) should the pressure hold in the high pressure side? 2) What could cause the low pressure to increase?

Background: I developed a very annoying small leak. Went through several 20lb tanks of CO2. Replaced all of the lines, the manifold, ball locks, keg posts and o-rings, and keg lid gaskets. No joy! Placed the manifold and keg lines in a bucket of water and found a leak in the manifold, which I fixed. Thought I was good. However, when I put a keg on gas it did not carbonate. Covered every connection with leak detector (including the stem on the CO2 tank) - nothing! Figured it must be the regulator so I bought a new regulator, which leads me to the two questions above. I'm at my wits end and am hoping the community can help.

 

[JONNYROTTEN]

No expert but the high pressure side reads the tank pressure right? That should always have a reading till the tank is empty.
I get low pressure reading increase sometimes after burst carbing from back pressure from the keg. Sometimes get a jump on one gauge if I'm burst carbing the other. I purge entire system including kegs THEN set psi and it holds.

No help I'm sure

 

[jalc6927]

Tighten all hose clamps and make sure o rings are not slit or damaged

 

[IowaStateFan]

Thanks guys. I probably wasn't clear. Only the lines were pressurized to 15psi then the valve on the CO2 cylinder was closed. The lines were not connected to the kegs, so back pressure from the keg can't explain the increase in pressure. It just seems odd to me. Wondering if maybe there is something wrong with the regulator.