Atwood Water Heater Not Igniting

[k0irl]

Hit the road yesterday from Denver with my 2004 International, headed for Gulf Coast. At our first stop for the night, found out the H/W heater is not working. When I turn on the H/W ignition in the bathroom, the light comes on and stays on (instead of coming on for 5sec and then off).

Called the local service center this morning (Windish RV in Denver, who I'm really not a big fan of) who had just serviced our unit prior to this trip) to make sure they hadn't shut off any LP valves to the H/W heater. They said no. Service Rep said if the light in bathroom is coming on, then that indicates power to the unit and it's probably not a fuse on the main panel. He said it's possible that the thermal cutoff fuse on the heater has gone bad and may need to be replaced.

For additional info, we drove through about 6 hours of rain last night before arriving at our first stop. At times, torrential. Would that do anything? Can't imagine, but thought I'd throw it out there.

How can I tell if the thing is even getting LP gas? I cannot see a valve on the unit where you can turn off gas and the manual does not mention a valve that I recognize.

When I turn on the light, I listen for any kind of clicking or spark at the unit, but see/hear none. Then again, my wife says I'm blind and deaf.

Any help would be appreciated before I call the service technician at our final destination on the Gulf Coast.

[Protagonist]

Originally Posted by k0irl

Any help would be appreciated before I call the service technician at our final destination on the Gulf Coast.

If you're headed to the Gulf Coast, will you pass near Gulfport, MS? If so, you could stop in at Foley RV to get your water heater checked out.

First bit of help, find out if the heater is working on electric. If it works on electric but not gas, then you know that the problem is somewhere on the gas side, such as the thermocouple. If it doesn't work on either, then it's on a system common to both sides, such as the thermostat. When my Atwood went out, it was a bad thermostat. What would happen on mine is that it would overheat, and then shut down and not restart when the water cooled off again. The fault light would remain lit as yours is doing.

[SteveH]

Your unit is old enough to have some corrosion set in on the electrical connectors, and those could cause the problems you are having. You might try cleaning and tightening all the spade lug connectors. All of the electric/gas water heaters that I have had in Airstream trailers (four now) have had separate thermostats for gas and electric operation.

[k0irl]

Protagonist @ SteveH - thanks for the advice. SteveH's advice may have been spot on. When I disconnected and reconnected the little 3-inch thermal cutoff wire (which seems to be a wire with a resistor on it?), the auto ignite started working again. Somewhat worrysome, though, is that the flame ignites - goes out - and then ignites again after a big POOF of LP buildup from a couple of seconds. Then seems to stay lit and the tank heats as normal. Don't like the idea of LP gas building up, so I'll probably have the unit checked out.

Protagonist - we're in Port Aransas TX - hoping for a trip that include Gulfport next year. Last time I was there was as a kid and we went with my grand-dad (whose USN Seebee unit was activated to help rebuild after a hurricane - Camille?). I was only 6 or 7. I'd like to revisit the area and those fond memories of hermit crabs and mile wide beaches at low tide!

Thanks to both for the advice.

[Antique Pedaler]

Wouldn't be suprised if that rain got your water heater wet. It's happend to me. The cure was to dry it out with a hair dryer and then it would light.

[lewster]

It's not a bad idea, especially with Atwood water heaters, to remove and replace all of the 1/4" spade connectors several times on a regular basis. That includes the white plugs connected to the potted control board in the upper right corner of the unit. This will clean all of the contacts and assure that the signals are getting to where they should be.

Atwood's insistence on placing all of these contacts on the outside of the unit, which exposes them to the elements, regularly have corrosion problems that cause unit malfunctions.

BTW, that little bent piece on the right side of the thermostat/ECO section (covered in black spongy foam) is called a thermal cut-off or TCO. It is positioned where it is to be a sacrificial element in case you get a back flame from the burner tube or have flames coming from the air intake in the LP delivery tube.

[A W Warn]

The WH in my Safari got wet in a foggy rain and the ignition shorted out, so I replace my 14 year old water heater. If I had it to do over I would just replace electronics and valve parts as needed. The tank was in perfect condition.
Before that replacement I had been having problems with corrosion on the connectors mentioned above. Also, the screw and eye where the ground (green) wire connects to the WH frame would corrode. You might want to clean that connection also.

[Bill M.]

On our old Atwood heater the stubborn ignition problem turned out to be a poor ground connection of the ignitor. Take the ignitor tube out of the heater and clean the contact area where it is screwed to the braced to hold it in. We had some rust there and when it got damp it would not ignite.

[sloprince]

Mine has a reset switch which often throws. It is located inside the heater a little white round breaker on a pipe with a button in the middle of it.

[cwf]

I was having a 'start, light, stop' problem.. WH would light, but go out after only a few seconds.. I removed the 'spark/flame sensor probe' wire where it connects to the board. there was little 'scratching' at all of the terminal. I squeezed the female connector to close the gap, thereby increasing the grip on the male terminal..

Problem almost solved.

Next, I bent the support probe support tab to have a deeper 'plunge' into the flame plume.

Works just fine now...! Hope it lasts! last time I did this was about 12 months ago..

[waninae39]

here are the replacement instructions