Close Liz: It's not the sparky things that are the problem though. At least not the problem, I'm suggesting.
I've noticed with mine that when the water gets close to the valve, inside the line, the flame dies down, is impossible to fix and a frost line rises up the tank.
I think that the water is coming into contact with the propane as it evaporates and the water turns to ice. Thus the line gets partially blocked at its narrowest point.
Either that or as you say, the sparky things are damp.
Cheers.
James Chap