A propane tank valve will vent built-up pressure that can result as the gas expands. The valves will also prevent the overfilling of the tank. There are several types of valves on the market, and each has specific uses. Sometimes it is necessary to reset the propane tank valve and here are the steps to show you how.
Step 1 - Check the Spring Valves
A spring valve is a relief valve that is held into place by a powerful spring. The pressure inside the tank should be lower than the pressure on the spring. When the pressure builds too much, the spring compresses and the excess gas is vented. If this needs to be replaced it's best to call a professional since the springs need to be calibrated correctly in order to work.
If you decide to check these on your own, you will need a manual for the tank itself as each propane tank may be slightly different. In most tanks, you can release the pressure by using the wrench to loosen the nut surrounding the valve. From here you will be able to reset if this is the issue.
Step 2 - Check the Internal Pressure Relief Valves
Most tanks found in home applications will use the internal relief valve. This creates a more mobile situation for the tank. Internal pressure relief valves need to be replaced by the tank manufacturer since they need to be able to access parts of the valve inside. This isn't something most people can replace on their own. To reset these, you simply need to depress the external portion of the valve until you hear a pop, then a hissing sound. Once the hissing dissipates the valve has been reset.
Step 3 - Check the External Pressure Valves
Most older tanks will rely on external valves. These work in the same fashion as the internal valves, but the entire valve is located outside the tank. These are much easier to reset than the internal valves. You will need to loosen the nut around the valve to do this.
Step 4 - Replace the Valves
Safety valves are designed to pop off if the pressure becomes too great. This prevents possible explosions from a tank that is under pressure. If you need to replace a popped off valve, you must call a professional.
A tank should be emptied before you attempt to work with a valve.
Most valves will have a protective casing around the valve to prevent grime and build up from obstructing the safety relief valve. You will need to remove the cover before you can reset or work on any valve.
Step 5 - Check the Pressure
Once you have reset the valve, you want to check the pressure gauge on the tank to ensure you haven't lost too much pressure. If the pressure falls dramatically then you won't get the propane needed to the appliance. If the pressure has built up, you will need to release the pressure or call a professional to do this for you.