Atwood Water Heater Will not Ignite or Stay Lit

[mando_man]

I'm having a problem with my Atwood water heater. It attempts to ignite, but then fails. I've replaced the TSTAT, ECO, thermo fuse (circled in green). You can see and hear the spark when it's attempting to ignite, but never catches (circled in blue). What I do see sometimes is ignites, but I see a small flame for a second or two where it's circled in red which does not seem right. Any thoughts?

Picture of Water Heater

[StirCrazy]

open that air slot untill you start to see yellow in the flame, then close it off untill there is just a tiny bit of yellow on the tips. right now your not getting enough air, it wont get any quieter but it will be adjusted properly. I have the same water heater and that sounds normal.

Steve

[dougrainer]

Adjust the air fuel mixture. It should just roar, not have small cut outs. Doug

[2112]

That's how my suburban sounds

[mando_man]

OK, so I pulled out the orifice and it was a little clogged. I also replaced the main burner. It ignites and stays lit. But now it has a noise. I've attached a video. It's hard to see because of the sunlight, but you can hear it. Is it the air mixture? Or is it the placement of the flame spread thingy?

Video

[BluegrassBill]

The air/gas tube is plugged-up (the part that is circled). Remove and clean, good to go. Spiders and stink bugs love to nest in the tube.

[dougrainer]

To the OP, IF that water heater is more than 10 years old, I would REPLACE the gas valve. Atwood gas valves usually fail to "seal" after many years of service. What they do is, if you have the W/H OFF, spray soapy water all over the orifice and wait got 5 minutes, keep the orifice wet with soapy water. Odds are you will get bubbles indicating a leak. When I do a Manometer test on older RV's and it fails, this is the FIRST place I look. Most times it is leaking. This is NOT the cause of your problem, but I would do the test and replace if it fails. Doug

[dougrainer]

JimK-NY wrote:
Again, replacing the ignitor should have been the first step. Maybe something else has failed but ignitor failure is pretty common.

Remember, he stated that AT the exit from the orifice he had a small flame. THAT would NOT indicate an Electrode problem. FYI, the main cause of electrode failure is the white porcelain has microscopic cracks and "bleeds" the spark voltage. Resulting in no or diminished spark. What the OP has found out, is, you cannot just start replacing parts. It gets expensive. Doug

[JimK-NY]

Again, replacing the ignitor should have been the first step. Maybe something else has failed but ignitor failure is pretty common.

[StirCrazy]

I would check that the ignightor is still properly gapped, althought it sounds like it is sparking, and before your go nuts try spraying compressed aire throught the compustion path and make sure there is nothing causing interferance with the air flow. I had a simular problem and it ended up being bugs.

[mando_man]

Igniter was not replaced, it’s sparking. Connections look good, all removed, cleaned and securely attached. All gas appliances work fine (fridge, heater, stove, oven). Continuity looks good. Have not checked orifice or banged on gas valve. Will try that next. That’s for everyone’s suggestions.

[JimK-NY]

The original post was confusing. Was the ignitor replaced? If not, that should be first on the list.

Next make sure all the connectors are clean and seated especially the connector array, upper right.

[dougrainer]

1. Small flame indicates a clogged orifice. Remove the orifice and clean with spray carb cleaner and compressed air.
2. Also indicates LOW or marginal LP gas pressure. Light the Stove/Range burners all 3 or 4. They should have a full blue flame
3. When it tries to ignite, tap on the gas valve with a hammer. IF the flame then comes ON, your gas valve is bad.
4. If the W/H is in a slide room, then the rubber gas line may be pinched. Doug

[enblethen]

Start by checking the ground on the gas valve. It is hidden behind the mounting bracket.
Check continuity on the TWO gas valve coils. They should read the same resistance.
I don't care much for the wires at the circuit board being so tightly twisted.
Forgot ask does your other appliances work OK?