ATWOOD Water heater - works on electric, not gas

kmb1966 wrote:
Update: I just got mine to ignite, but I am still not sure what is wrong. I got it to ignite by touching the brown wire that connects from Tstat (has a thermal fuse looking thingy on the brown wire), When I held it, I could her something "click" slightly. Holding the wire steady after hearing the slight click sound for about 3 seconds, the igniter fired, and the water heater is now heating on gas. Letting it run for now. must be some sort of bad connection or goofy thermal fuse problem?

Bad terminal connections.....clean and tighten them

The thermal fuse does not reset, and opens on high heat.

Update: I just got mine to ignite, but I am still not sure what is wrong. I got it to ignite by touching the brown wire that connects from Tstat (has a thermal fuse looking thingy on the brown wire), When I held it, I could her something "click" slightly. Holding the wire steady after hearing the slight click sound for about 3 seconds, the igniter fired, and the water heater is now heating on gas. Letting it run for now. must be some sort of bad connection or goofy thermal fuse problem?

stew47 wrote:
Yes good point. I'll start one.

See my reply in this thread.. That applies to the modern single set of T-Stats Atwoods.

In fact it applies to all Direct Spark Ignition Water heaters. Attwood, Single or dual pair of T-Stat models. Surburan, and "other".

Yes good point. I'll start one.

stew47 wrote:
Ok I'm subscribing. My model is gc10a4e Atwood. Same thing works on electric. Doesn't on propane. This is on a new to us 2010 crossroads and to be honest I didn't try it when I bought it. They said it worked so... I think they only used on electric as well. I do know I have 12 volts leaving inside switch and that's as far as I made it.

Your model is completely different....only has one set of t-stats for both electric and propane so your propane problem is different

You should start your own thread vs hi-jacking OPs for a more in-depth discussion

Ok I'm subscribing. My model is gc10a4e Atwood. Same thing works on electric. Doesn't on propane. This is on a new to us 2010 crossroads and to be honest I didn't try it when I bought it. They said it worked so... I think they only used on electric as well. I do know I have 12 volts leaving inside switch and that's as far as I made it.

Is it fused at all inside the camper in the power center? And did you check that fuse?

Your model/vintage of water heater uses 2 separate sets of t-stats for electric and propane

Electric has it's own set on backside of water heater where the electric element is

Propane has it's own 12V DC set in outside compartment (ECO----high temp t-stat and T-stat----normal temp t-stat)

Brown wire comes from circuit board to/thru a 'thermal fuse' (one shot fuse inside clear tubing) to & thru normal t-stat and back to circuit board

Red wire comes form circuit board to & thru ECO then to gas valve

If 'thermal fuse' has blown......no DC so no propane function
It normal t-stat has failed or bad terminal/contacts...no DC so no propane function
If ECO t-stat has failed or bad terminal/contacts.....no DC so no propane function

With propane On/Off switch on......check for 12V DC on Brown & Red wires.
Trace where you loose it

If thermal fuse has blown..........need to clean burner/combustion chamber
Thermal fuse blows at 190*F due to blow back of propane flame due to obstruction/blockage in combustion chamber/burner

Mine did the same, turned out to be the control board.....

Atwood, on many devices (I know furnace best) uses a single wire flame sensor/ignition system.. During Direct Spark Ignition phase it's hauling aroudn 1,000 volts A/C (Based on the size of the spark gap) See note on that.

Then it switches to flame sense it's looking for less than 1/2 volt (480mV)

Imagine if the switch does not go properly, the half volt senistive chip is hit with 1414 volts (Peak voltage for 1,000 AC) and .. Pop goes the flame sensor chip.

I think that is what happened to my furnace.. So, it seems, does dinosaur boards cause on the replacement control board they put a nice little gas discharge tube in the ideal spot to deal with just that issue. I am assuming that is why it is there.

On my Water heater, when it did what yours is doing, New control board fixed it.


NOTE: before throwing money at it, make sure of the following:
1: You have propane
2: Do a Full PM on the burner (make sure the oriface is not clogged by spider web)
3: Check the spark gap, Overly wide spark gaps are common in DSI devices it seems.