We have had several roofers bring their torches in for repair or return them to the distributor claiming there is no propane pressure to the torch. There have been changes in LP tanks recently, for safety reasons that may be the cause of this lack of pressure. Tanks and some POL adapters now have a safety shut off check valve that can stop the flow of propane in case of a burst hose.
1. 
The most common reason is that the operator has opened the valve on the propane tank too quickly and it has activated a safety shut off check valve in the brass POL attached to the regulator. To reset this shut off valve you need to close the valve on the tank and completely remove the regulator from the tank. You’ll want to close the valve on the regulator (turn knob counter-clockwise until it turns without tension). Then re-attach the regulator to the tank and slowly reopen the valve on the tank. Now turn the regulator pressure adjusting knob five to seven turns clockwise.
2. If your propane tank is ten gallon capacity or less it has an OPD (Overfill Protection Device) valve that has a safety check valve in it. This is used to stop the overfilling of a tank and stop the release of fuel if there is nothing attached to the valve. If you do not screw in your regulator POL fully into the tank then this check valve will not allow the outflow of propane. Tanks of 12.5 gallons or more do not have this and have no restriction on the flow of propane. This is the reason most roofers who do torchdown prefer the larger tank, but you still want to make sure the POL is firmly screwed into the tank valve (remember it has reverse threads on the nut).
The vast majority of the time we get the torch back up and running just by resetting the check valve in the brass POL attached to the regulator. If you follow these tips, you will stay on the job, and not have to head back to your distributor to trade in your torch.
