Suburban SW6D Ignition Issue?

[jwchenault]

I recently went on an extended trip covering 3500 road miles with several 3-4 night stops along the way. at the first stop the water heater worked perfectly, at the second stop it worked perfectly until day three. As I was showering I heard what sounded like someone slamming one of the cargo compartment doors, I exited the shower to find the water heater fail light on I immediately reset it and it seemed to light normally. Next morning while shaving again heard the cargo door slam sound accompanied by the fail light. I simply turned it off and proceeded to my next stop. Being still under warranty I phoned the manufacturer of my unit and was told to check the burner tube for obstructions as well as the orifice. I removed the burner tube and orifice and could find no obstructions in either disheartened I reassembled everything turned on the switch and to my surprise it lit right up and worked perfectly for the next two days until I moved on to my next stop, there the beast reared its ugly head once more. this time I simply opened it up and wiggled every connection I could find turned the switch on and viola it worked for 4 days without fail. then again failed with the typical door slamming sound this time without moving the camper. I contacted an authorized service center and was told they would gladly work on it under warranty however manufacturers warranty does not include coverage for an emergency service call which would cost me $75 out of pocket unless I could bring it in and leave it at their shop and they could get to it in about a week. the tech I spoke with was very nice and told me he had run across this problem before and that it was more than likely the ignitor and told me to look for any cracks in the ceramic and that it was about a $20 part at any RV supply. So with my trusty screwdriver I removed the screw holding the ignitorin place and removed the ignitor upon very close examination i can see two cracks in the dull ceramic surrounding the ignitor rod but they do not extend into the shiny glazed ceramic. My question is could this still be my problem or am I chasing rabbits? I'll gladly spend $20 if it will correct the problem.

[Old-Biscuit]

Gas solenoids get 12V DC for 6-8 seconds while Spark Electrode gets power

Gas valve should pop open when solenoids are energized.

You can test solenoids....disconnect wiring and check resistance across solenoid. Should be 40-44 ohms.

Sounds more like spark was not in right place. Now it is.
Although there isn't much in the way of adjustments with mounting bracket/screw you can bend electrode some just keep gap 1/8"

[jwchenault]

My first TT had a Suburban 6 gal standing pilot WH I had that unit 12 years and never had an issue with the WH Sometimes Technology Sucks! Just Sayin!

[jwchenault]

Old-Biscuit wrote:
Ceramic should be solid..no cracks.
Cracks allow high voltage used for spark ignition to go to ground vs creating spark at ground rod and in path of main flame.

Also spark electrode position can cause same issue........tip of electrode must be engulfed by main flame.

Burner tube flame spreader at end of tube must be squared/parallel with end of tube for proper flame disbursement

I thought I could see a couple of hairline cracks right where the igniiter rod exits the ceramic (dull chaulk looking part) but they did not extend out into the shiny glazed portion of the ceramic so I took it to a local dealer who tested it and said that there was nothing wrong with it I think he put it on a hypot and tested it for leakage at double the spark voltage. anyway I took it home and reassembled it trying to get the igniter closer to the center of the burner tube (there is very little adjustment possible!) it ended up with the electrodes centered horizontally but in the upper third of the burner tube vertically. I turned it on and it lit almost on the first spark. tried it several times and it never failed to light however this is par for the course as this has been a very intermittent problem. the tech at the dealer suggested that the gas valve may be failing to open enough to light on the first try but is releasing some gas which is collecting in the combustion chamber until ignition does occur with a bang! Your Thoughts?

[Old-Biscuit]

Ceramic should be solid..no cracks.
Cracks allow high voltage used for spark ignition to go to ground vs creating spark at ground rod and in path of main flame.

Also spark electrode position can cause same issue........tip of electrode must be engulfed by main flame.

Burner tube flame spreader at end of tube must be squared/parallel with end of tube for proper flame disbursement