In order for your propane tank to pass a safety inspection, it must both be free of rust and have an OPD, or overfill protection device. Older tanks are not fitted with an OPD, so they will not pass an inspection even if they are in perfect condition. Rather than replacing your whole propane tank at great expense, however, you can simply replace your propane tank valve. OPD valve replacement is fairly easy and can be done at home.
What Is an OPD valve on a Propane Tank?
As the name suggests, an OPD valve is designed to prevent overfilling of a propane cylinder. Once the tank is full, the OPD closes, preventing any more propane from entering the tank. It was designed as a safety mechanism to help prevent propane cylinder accidents. They're required by law on all propane tanks of 40 lbs or less.
How Will You Know It Needs Replacing?
The vast majority of propane cylinder valve replacements are required because a prone cylinder does not have an OPD. This would mean the cylinder is not compliant with safety standards. Replacing an out-of-date propane tank valve with an OPD valve will mean you don't have to replace your entire propane cylinder, which can save a lot of money.
How Can You Replace a Tank Valve on a Propane Tank?
The first thing to do when replacing a propane tank valve is to ensure the cylinder is empty. You should use the propane you have left and not just release it into the air. Once the tank is empty, close the valve by turning the handle fully clockwise.
You'll need to place the tank in a secure position, either using a device or asking a friend to hold it still. Using a heat gun, soften the weld between the propane gas valve and the cylinder. Open the propane tank nozzle to bring the tank to regular atmospheric pressure.
Next, turn the valve counterclockwise using a pipe wrench to remove it from the cylinder. You can discard this old valve.
While you have visibility to the inside of your tank, take the opportunity to check for rust. If the inside of your cylinder is rusty, it is no longer safe and must be thrown away. You should also make sure your tank is free of moisture to prevent future rust. This can be done by adding a small amount of anhydrous methyl alcohol.
You can now attach your new OPD valve. Thread it into the bung of your propane cylinder, then tighten using a pipe wrench.
The next time you refill your propane cylinder, tell the merchant that you have recently replaced the valve. Licensed fill stations can then perform an air purge and leak test to ensure your OPD valve replacement was successful and your propane cylinder is safe to use.