How (or why) did my tank percentage fall so quickly?
This question is often asked during the period immediately following the delivery, or sometimes several days later. Whether the propane tank is being filled partially or completely, the bleeder valve is always used during the delivery process. It is common for the delivery driver to write the ending percentage on the fuel ticket after the delivery which is often 80%, if the tank has been filled. Even if the face gauge reads 75% following delivery, the tank is at 80% because the bleeder valve indicates the actual propane liquid level (above 80%) in the tank, not the face (dial) gauge.
Another instance that may seem confusing to propane consumers involves tank volume following a propane delivery in the afternoon, which is commonly the hotter part of the day. When propane deliveries are made during the hotter parts of the day, the gas has already expanded before it is delivered into the tank and the gauge may read 80% following a fill. Inspecting the tank gauge the following morning may show a significant percentage drop (up to 5%) even if no gas has been used! This does not necessarily indicate a leak. More likely than not, the volume of liquid propane in the tank has contracted in the cooler overnight hours.