Co2 tank not staying at constant pressure???

Sounds like you have a bad regulator. Tough to say without looking at it but that would be where I would start troubleshooting.

 

Yeah I would definitely try a different regulator.,

 

Also check the duck bill seal where the CO2 goes into the coupler. They sometimes get gummed up and don't open freely. It should be pliable and easily open.

 

Once you set the pressure, you should get numerous pours (from gas in headspace) even if you disconnect the tank. What are you doing to "reset" the pressure? Are you saying that after one pour the headspace pressure (gas in top of keg) is zero (pull relief valve to check)? Are you sure the CO2 tank valve is fully open (CCW)? Give us a few more details.

 

From your description, it sounds like the keg is not pressurizing as the result of the CO2 being restricted. To be sure, here's a couple more tests:

When reg reads 10-12 psi, pull your relief valve . . . you should get a steady Pfffft . Repeat this test with the gas line disconnected from the keg, the Pffft should taper off to zero as the headspace empties. If the headspace is not pressurized you will get little to no Pfffft.

Next test; with the reg set at 10-12 psi, disconnect the gas line from beer keg and depress the center pin on the quick disconnect. This mimics connecting to the keg and you should get a steady rush of gas which (if everything is working correctly) will continue.

If these tests don't give you a steady flow of CO2, then I recommend disconnecting your gas line from the shut-off valve coming out of the reg. Then re-open the valve, CO2 should flow unrestricted. If still no steady gas flow, then disconnect reg from tank, then slowly open the tank master valve and listen for gas flow.

Don't worry about wasting CO2, these amounts are insignificant. What you are doing is starting at the keg and working backwards to the CO2 tank. You are looking for the "choke point" that is preventing the gas from flowing. This could be tank-post, quick disconnect, shut-off valve, regulator, tank master valve, or empty tank. At some point you should be able to isolate the problem.

 

What did you do that made it work?

 

Doh!