How much propane does my tank hold?

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Lou Schneider

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85% of 39 gallons, or 33 gallons. You need room in the tank for the propane liquid to expand into if the tank warms up after it's filled.
 

Isaac-1

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Look at the data plate on the side of the tank, it should show the WATER CAPACITY of the tank in gallons, your propane capacity will be 75% of that. Advertising documents may show water capacity or propane capacity
 

Rob&Deryl

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On the road from mid NH
Another reason to leave space is the tank is full of liquid but you need gas to burn. The available surface area affects the flow rate of evaporation. An example… I had a (almost commercial) stove and a 20kw generator at my house - the only propane loads. I had asked the gas company to install a 100ish gal tank. They said they needed to do 2 in order to have enough surface area to supply the demand of my loads.
 

CharlesinGA

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50 miles south of Atlanta, GA
Its 80%, not 75 or 85.

Was discussed in late November in THIS THREAD.

Here is what the data plate on the tank looks like. On this one about half way down on the LH side it says WC 12.1 which is "water capacity 12.1 gallons" times .8 is 9.68 gallons of propane capacity. The tank has to have a "air space" or "vapor space" above the fluid for expansion and for a place for the vapor to form (it leaves the tank as a high pressure vapor)

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Here is a cutaway of a typical tank so you can see what all the fittings and valves do.

Charles
 

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NY_Dutch

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Where our wheels take us!
The cutaway photo is good, however the "vapor pressure relief valve opened during filling..." is an incorrect label, yes, it is opened during filling, but not to relieve any vapor pressure. The official name for the valve and pipe behind it is the "Fixed Liquid Level Gauge", and it's purpose is to positively indicate a full (80%) tank when the escaping vapor turns to liquid. The OPD (Overfill Prevention Device) float and valve is a back up to the Fixed Liquid Level Gauge.
 
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