one year old unit.......getting intermittent ignition failure. At one point it just would not turn on......no pilot flame. I replaced gas valve and then it worked....for awhile. The other day, which happened to be rainy, I experienced ignition failure again...exact same signs so likely gas valve was not the problem. I was going to start checking voltages today and of course the unit fired up. I don't see any loose wires...no corrosion. Any ideas?