Ok, I'm afraid that I must report that I have joined the ranks of those having problems with AS&S regulators. Here's my info, please feel free to make any comment you think will help.
Up until this weekend I had one regulator, on 5 way manifold, and 4 checked gas-out to ball lock connectors. No leaks, 4 kegs under pressure since about a year ago. Since I recently added soda to my fridge, I wanted to expand my available pressures and purchased 4 used Perlick secondary regulators from American Science and Surplus. To go with that, I purchased 4 new gauges from abibeverage (eBay), three 1/4" brass M-M nipples from Lowes, and 2 more checked NPT->MFL valves. So now, my setup looks just like post #14
except that I have a valve on the left where the gas comes in and my gas-out connections are MFL, not barbed. All threads were liberally coated with paste pipe thread sealant prior to assembly.
Here's where the fun begins.
Sat AM - I installed my new reg bank in fridge checked the MFL fittings with soapy water, and pressurized her. As a test, I shut off the tank and all 4 gas-out valves. Within minutes I noticed that #2 and #4 (left to right) were dropping slowly. Since at least one of my valves had turned during assembly, I suspect they weren't tight enough.
Sat PM - I pulled the assembly out, benched it, and turned *all* fitting at least one more revolution. Now, they are definitely NOT too loose. If anything, they are too tight. Put her on the bench and gassed her up. While I let her sit, I applied more pipe sealant around all the junctions for good measure. I noticed that couple of gauges (not just 2&4) dropped, but only when they were turned away from me. I guessed that for whatever reason, they didn't like being rotated. So I turned it face up, pressurized the primary to 28psi, all secondaries to 20psi, closed the tank, and let her sit still. 1hr later, all gauges were still at 20psi. So I dumped the system and repeated the exercise. Same results. Happy that I had a simple seal problem, I reinstalled her and pressurized the system, being careful to close tank before retiring.
Sun AM - I checked the system and found the primary gauge at 15psi, gauge #1,3,&4 at 10psi (as expected), 2 at 15psi. Repeated exercise closing the valve to the primary gas buss and all gas-out. Returned 2 hours later to find primary line at 28psi (as left), #2&3 at 0, #1 & 4 at 10psi (as set).
Sun PM1 - Repressurized system, closed tank and all valves (again). 2hrs later found the primary gauge still at 28psi, gauge #1 at 10psi (as expected), 2,3,4 at 0psi.
Sun PM2 - Repressurized system, closed tank and all valves (again). 2hrs later found the primary gauge still at 28psi, gauge #1,4 at 10psi (as expected), 2,3 at 0psi.
Sun PM3 - Repressurized system. Opened tank and all valves. Returned 2 hours later to find primary line at 28psi, 2nd gauges as expected. Closing all valves now.
EDIT: After 7 minutes #1,3,4 are at 12psi (normal), #2 is at 5psi, primary is normal at 28psi.
EDIT: After 80 minutes #1 is still at 12psi (normal), #2,3,4 are at 0 psi. primary is normal at 28psi.
EDIT: After 3 hrs #1 is still at 12psi (normal), #2,3,4 are at 0 psi. primary is normal at 28psi.
EDIT: After 10 hrs #1,2,3,4 are at 0 psi. primary is normal at 28psi.
What I know
* Nothing leaked on the last bench test
* The gas-out lines, crimps, and connectors are not likely the problem as they have been in service, and the leaks still happen with them valved out.
* It's not the tank nut, the primary regulator, the hose into the fridge, the flare fitting into the regs, or the 1st valve (up to the ball) as the primary line never looses pressure when the gas-in to the manifold is closed.
* The #1 regulator is the only one that does not ever appear to leak down. It has a NPT-MFL valve that is not checked.
* The #2 regulator seems to leak down every time. It's also the only one at 25psi.
* The #3 and #4 seems to leak or not leak somewhat randomly.