Propane guides

Short answers to the questions people ask at the fill station. Each one links back to the finder.

1. Propane refill or tank exchange: which costs lessA refill puts about 20 lb in your tank; an exchange gives you about 15 lb in a different one. How to compare the two prices and when each makes sense.
2. How much propane a 20 lb tank holds, and how long it lastsA full 20 lb cylinder holds about 4.7 gallons and 430,000 BTU. What that means in hours of grilling, heating or cooking.
3. Can you refill an expired propane tankGrill cylinders carry a date and must be requalified after 12 years. What the stamp means, what a refill station will do, and your options.
4. What the OPD valve is and why a station may refuse your tankThe overfill protection device has been required on grill cylinders since 2002. How to recognize it, how it works, and what to do if your tank lacks one.
5. How to tell how much propane is left in a tankThree ways to check a grill tank without a gauge: weigh it, use warm water, or read an inline gauge. What the numbers on the collar mean.
6. How propane refill works at U-HaulU-Haul fills grill cylinders, RV tanks and forklift cylinders by the gallon at more than a thousand stores. What to expect, what they fill, and how to find one.
7. How propane refill works at Tractor SupplyTractor Supply fills propane cylinders by the gallon at its farm stores and sells exchange tanks. What they fill, when to call ahead, and how to find a store.
8. Propane autogas basics: filling a vehicle, not a cylinderAutogas is propane burned in an engine. How the quick-connect nozzle differs from a cylinder fill, where the pumps are, and who uses them.