Originally Posted by arf145
....Related question: the tank has a pressure gauge. Does this in any way tell me how full it is?
Even if the tank guage was calibrated and reliable, pressure increases with temperature, so its not a good indication of volume. Chef is right, most accurate at zero.
If the pressure gauge comes after the regulator, its not tank pressure, but regulated pressure. That shouldn't change at all, when pressurized, until the tank is empty. It can be useful, if installed after the solenoid, to see if your system is holding gas after everything is shut off. However, if not testing, you should always burn off the excess gas in the hoses, by shutting off the solenoid with the burner on and letting it burn off.