[Festus2]

Joe:
If your have the Marshall 254-00 regulator (auto change over), this is taken from their manual which states:
"Make sure there is propane in both cylinders before you start. Rotate the black lever on the top front side of the regulator toward the cylinder you want to use first. This will be the "service" cylinder and the other will be the "reserve".
Slowly open both valves. The indicator on the top of the regulator will turn green. This will stay green as long as there is gas coming from the service cylinder. When the service cylinder empties, the regulator will start drawing from the reserve tank providing an uninterrupted flow to the system.
When it switches over, the indicator will change from green to red. The red color shows that the service tank is empty and needs to be refilled.
To remove the empty tank, rotate the black lever all the way over to the reserve tank. The indicator should now turn green and the reserve tank now becomes the service tank.
Now, shut off the cylinder valve on the empty tank. Then disconnect this cylinder and have it refilled. After refilling, reconnect the pigtail and slowly open the tank valve. The full tank now becomes the reserve tank."

Not sure if this helps at all or will leave you, still frustrated, on square one.