Originally Posted by Lew on Harmony
Our propane tank emptied and we replaced it. However, the solenoid won't come on any more. Any help greatly appreciated.
You absolutely need to take the solenoid far away from the tank before you attempt to repair it. You also really need to know all about the internal operation of solenoid valves -- they involve an inductive coil which, if tinkered with the wrong way, can produce sparks which will ignite your propane, you, and everything else near you.
You need to determine the inductance of the solenoid coil. The two wires that connect to the solenoid will connect to that coil, you can use a multimeter to measure that. There are usually several solenoids of the same type in any gas fitting apparatus, they should all have nearly the same inductance. If yours is out then (a) measure the DC resistance of the coil, and (b) measure the voltage across the coil with the current applied to the solenoid (i.e. "shut off" switch on).
The DC resistance of the coil should be nearly zero. If it is very high, you have a dead solenoid. There is no safe repair option here, throw it away and buy a new one.
The voltage across the coil should spike up very quickly as you apply the current, then drop away fairly quickly afterwards. If it stays high or ties to zero then you also have a dead solenoid.
If you really aren't sure then get an electronics expert or marine electrician to have a look at it for you, or if in doubt just replace the unit.