Some OPDs were made before they were required to have the letters printed on them. Check the label or wrapper on your tank if it has a triangular valve but doesn’t have OPD printed on it.
Cut off the label around the body of the tank and check underneath it for rust or cracks.
If your tank was recertified, there may be a second date printed on the collar with the letter E next to it. Use the most recent date rather than the first one printed. Get your propane tank recertified 12 years after the first printed date and every 5 years after.
Propane in typically measured by weight rather than volume.
For example, if your tank has a tare weight of 20 pounds (9. 1 kg) and it weighs 22 pounds (10. 0 kg) on the scale, then it still has 2 pounds (0. 91 kg) of propane left. Make sure the scale and tank are on a flat surface so they don’t tip over while you’re filling.
You can buy connector hoses and propane fittings from your local hardware store. If you don’t have a propane supply tank on your property, you may need to go to a propane dealer where they can fill your tank for you. If you’re filling a 1 pound (0. 45 kg) propane tank, you can buy a connector that attaches to the larger tank.
If you’re filling an empty 1 pound (0. 45 kg) propane tank, then you can put it inside a freezer for 30 minutes for you fill it to make it colder.
For example, if your tank can hold 20 pounds (9. 1 kg) of propane and the tare weight is 20 pounds (9. 1 kg), stop filling the tank once the scale reads 35–36 pounds (16–16 kg).
