Atwood Water Heater won't stay lit.

[CRMW]

I have an Atwood GC6AA-10E Water Heater. Since I got the trailer last summer, the hot water heater won't work on gas. It will light, run for 2 or 3 seconds and turn off. If I bypass the controls and hook up 12v directly to the gas valve it will run but the ignighter does not get red hot. The flame ignighter/sensor appears to be in the right spot, and the flame appears weak.

So far I have:
Replaced the igniter/sensor - both work the same
Tightened all connections
cleaned the orifice
cleaned the flue and burner tubes
had the dealer verify the board
bypassed the ECO and Thermostat when testing and replaced them
used a bbq regulator hooked up directly to the gas valve
cleaned the gas valve with throttle body cleaner
verified the solenoid valves are working in the gas valve by checking them 1 solenoid at a time

Any ideas would help. It would be nice to have access to another gas valve to test it but I haven't been able to locate one.

Thanks for your time, Chris

[CRMW]

Hi All

I found the problem. The gas valve at the water hearer has what appears to be a second regulator in it, and it was shot. I found a guy that sold me the entire control system for $40, changed the gas valve and it lit and stayed running.

I took the old gas valve apart and there was some minor corrosion on the valve plunger seats and rust sitting on top of the rubber diaphragm.

Thanks to all for your help.

Chris

[PaulJ2]

On my trailer gas valve control, there was a flat head screw about half inch in diameter. Removed this with a screw driver and under this cover was a small adjustment screw. Turning this made the pilot flame higher or lower.
Might look there.

[Sez_Hoo_]

At the end of the burner assembly there is a round metal tab that sticks up in front of the burner tube opening. If that is broken off the flame is not going to burn right and can cause your problem. Also If that tab is in place try taking off your spark electrode assembly it is also you flame recognition circuit. Clean it up with some sandpaper. The slightest bit of rust will prevent the small current from passing through to the control board.

[Joe417]

I think Newman fulltimer may have touched on a possibility. You said the flame looks weak. Does the BBQ regulator work at the correct pressure? I've never measured a BBQ regulator. Does the frig, stove, and furnace work and if so will they work together?

Sounds like you're mechanically capable.

Measure the pressure at the input to the gas valve. It should be about 11" water column. It should maintain something close to that with other appliances operating. That would positively rule out the regulator.

You can make a manometer out of clear plastic tubing from Lowe's. Put a little food coloring in the water. There are examples of how to do it on the web.

One thing to remember if using a homemade manometer, the measurement is made from the level of one leg to the level of the second leg, not from the zero level to the level of a leg of the tube. You can use the zero as a reference, but you have to multiply X 2, and reading the differential of the legs will be a bit more accurate.

Yes, I've done it, took me an while to figure out what I had done wrong, and I don't usually forget when I've done something incorrectly, once I see my error. Although I'm over 60 so who knows what I'm forgetting.

[Old-Biscuit]

CRMW wrote:


I just hooked up the orifice directly to the regulator bypassing the gas valve and I can get a much better flame. Leaves me to believe the gas valve itself isn't letting the gas flow properly.

Hooked up orifice to regulator......????

Which orifice....the one that is screwed into gas valve?


Have you 'measured' the gas pressure at the WH gas valve??


Have you checked that BOTH solenoids on gas valve are getting energized?


Weak LP Regulator could be issue IF other propane appliances (furnace/stove top burners on HIGH) are not functioning properly
OR
It could just be bad/weak solenoid(s) on gas valve or a clogged Main Orifice.

[Old-Biscuit]

Artum Snowbird wrote:
"That 'thermal link' kills ALL DC so nothing would work....electric or propane"

I think you mean 12 volt electric here, not positive, but pretty sure mine worked on 120 volt hot water heat. I think my unit was not used for boondocking, hence they never knew, or did, but nobody tested it until I did.

2004 models and newer...........ALL use DC to make/control electric and propane

Thermal fuse trips......no DC.....no operation....120V AC (electric element) or 12V DC propane
Electric element 120V AC is triggered by a DC Relay

[newman_fulltime]

More than likely your regulator is failing causing weak pressure

[CRMW]

In my testing, i bypassed the thermal link, ECO and thermostat and it still the same issue. When the thermal link is shot, i don't think you get any gas or spark.

I just hooked up the orifice directly to the regulator bypassing the gas valve and I can get a much better flame. Leaves me to believe the gas valve itself isn't letting the gas flow properly.

[Artum_Snowbird]

"That 'thermal link' kills ALL DC so nothing would work....electric or propane"

I think you mean 12 volt electric here, not positive, but pretty sure mine worked on 120 volt hot water heat. I think my unit was not used for boondocking, hence they never knew, or did, but nobody tested it until I did.

[CRMW]

The problem seems to be the flame isn't strong enough to get to the flame sense probe. when I heat it up with a propane torch, the water heater will run

[Old-Biscuit]

Artum Snowbird wrote:
Not sure if you have done this. There is a wire that goes in the front of the water heater with a fusible link that is designed to cut off the power to the gas relay if the fusible link melts because of a fire outside of the burner.

My fusible link was not melted, but the connection at one end of the fusible link was rotten and corroded preventing anything happening. Like you, I took the board in and it tested fine.

Once I peeled off the shrink cover over the link, I could see the problem right away, and remade the connection with a new squeeze connector and then it all worked fine.

That 'thermal link' kills ALL DC so nothing would work....electric or propane

OPs issue is spark electrode NOT being engulfed in flame, loose/dirty contacts on 'high tension' wire (at transformer and/or electrode), cracked ceramic (signal tracking to ground) OR bad circuit on control module

[Artum_Snowbird]

Not sure if you have done this. There is a wire that goes in the front of the water heater with a fusible link that is designed to cut off the power to the gas relay if the fusible link melts because of a fire outside of the burner.

My fusible link was not melted, but the connection at one end of the fusible link was rotten and corroded preventing anything happening. Like you, I took the board in and it tested fine.

Once I peeled off the shrink cover over the link, I could see the problem right away, and remade the connection with a new squeeze connector and then it all worked fine.

[azrving]

I did all the same stuff except have the card tested. In the end the card had to be the problem but with my water heater being 14 years old and the card costing about $125.00 and us being ready to leave for the winter, I chose a new WH on Ebay for $350.00

[Chris_Bryant]

The electrodes need to be in the flame- temperature does not matter, being in the flame matters, as the board passes a very small electrical current through the flame.
It is possible that the board is actually bad- I have had some test good, but fail in use.