Signature Propane explains propane tank valves
Service Valve
Main shut off valve for the service line(shuts off gas flow).
Fuel Level (%) Gauge
Shows the percentage of fuel in your tank, but NOT a gallon gauge.
Regulator (not shown)
This device continuously regulates downstream pressure.
Pig Tail (not shown)
Connects the service valve and the regulator.
Fill Valve
Valve through which the tank is filled.
Relief Valve
Protects the container from excessive pressure.
Fixed Liquid Level Gauge
Gauge used by driver to tell if the tank is properly filled.
Vapor Return Valve
Used for tank evacuation

Reading Your Tank’s gauge:

Most tank gauges read in percent. To convert the percent of propane in your tank to the gallons of propane in your tank refer to the chart below.

If your gauge reads: 150 Gallon Tank: 250 Gallon Tank: 500 Gallon Tank: COMMON PROPANE TANK GAUGES:
80% 120 200 400 Common propane tank gauges
70% 105 175 350
60% 90 150 300
50% 75 125 250
40% 60 100 200
30% 45 75 150
20% 30 50 100
10% 15 25 50

More Know-Your-Tank info can be found by visiting: Propane101.com