As with all procedures dealing with RV propane tanks on your motor home, it is essential when opening the LP valve that you take care not to rush the process or damage any of the components. If you open the valve on your RV propane tank too quickly, you risk tripping the excess flow valve and having to fight to go back and forth with the system to get it to cooperate.
The excess flow valve is a spring-loaded needle valve designed into the POL or connection valve and is rated to a specific flow or pressure. During normal operation, the valve stays open to allow the LP to flow to the appliances. If there is a leak in the system at an appliance or an LP line, the excess flow or pressure is detected by the spring and needle seat and is pushed to the closed position to prevent filling the rig with propane. To help walk you through the method, Dave Solberg teaches you a simple tip to avoid any problems when reconnecting your DOT cylinder after getting it filled. Often times owners simply connect the POL valve and crank it open and the initial “burst” of air and LP is greater than normal operation pressure and the valve will close. It will take several minutes for the system to backflow to the appliances and the valve to readjust to normal operation. Dave shows a cutaway section of the excess flow valve and how to open the LP cylinder valve slow enough to eliminate this issue.
If you run into any further trouble when opening the LP valve and disconnecting your RV propane tank from the main line, you should consider driving your vehicle into a certified filling station to have a trained technician take a look. An expert can help show you the correct way to open the valve and even explain other techniques for dealing with and maintaining your RV propane cylinder. Also, you can refer to your model’s user manual or online discussion boards if you encounter issues.
Other than opening the valve slowly to begin with, the rest isn’t clear as to what to do if it happens?
If the excess flow valve is activated the best thing to do is disconnect the gas connection from the tank, open the valve to a stove top burner and let it sit a few minutes. This depressurizes the system and lets the valve relax and open up. You then close the stove burner, attach the gas line to the tank and open the valve slowly to try again. If it still doesn’t work, let it sit for a while longer and try again. I have seen these valves get stuck many times and if this doesn’t help, you might have to replace the pigtail as this is where the valve is located.
RV Repair Club Technical Expert