RV Repair: atwood furnace, ground electrode, ignition electrode

Question
Darren,
 I have a 2002 model 7900 11 furnace in my towable camper.  In the middle of the night the furnace stopped working. Up until that point it had been working fine. There is plently of gas in the tanks and can be smelt coming out of the exhaust outside during attempts to ignight furnace.  I have removed the wire to the ignition electrode and and placed it near ground to see if I have spark and I do. I have to get it less than 1/8" away to get it to spark.  Removed electrode and screwed bracket to ground and reconnected the wire to it.  Attempted to turn on to check for spark on electrode gap and there is none.  Set gap on electrode and ground probe very close to each other and I still don't get spark.  Is it commom for these electrodes to go bad so early in their life.  It has been barely used.  I am hoping the ignition pcb is not the issue.  Any info you can give would be appriciated.  Also could you copy your reply to scott.conner@asml.com  Thanks    Scott

Answer
Scott,
     It is fairly uncommon for the electrode to fail so prematurely.  It sounds like it may be shorted to ground internally.  The gap between the spark electrode and the ground electrode should be 1/8".  You might want to check the voltage at the furnace, low input voltage can make the PCB do some erratic things.  If neither of those is the case then it may very well be the PCB.  I hope this helps.

Darren