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pflightnut · 08-12-2022, 06:10 PM

The fault light came on yesterday on the Atwood WH. It did reset when I turned off both switches (12V and 120V). So I guess that's good. However, after reading a bunch of the posts on the topic on this forum, it seems like maybe I could be experiencing the first symptoms of a thermostat failure that the ECO thermostat caught. And most posters seem to replace both to accommodate the aging out the little beasts. U.s that the consensus?

Thanks,
Steve P

Old-Biscuit · 08-12-2022, 07:18 PM

Fault light can be triggered by:
Gas flame not lighting/not Proving it lit
ECO tripping on gas or electric

Gas Flame no lighting/proving-----
Spark Electrode issue (provides HI Voltage for ignition and return path for milliamp flame rectification current)
*Dirty/soot-carbon built up (inhibits milliamp return)
*Loose/corroded wire connection (inhibits milliamp return)
*Loose wire inside the ceramic insulator (inhibits milliamp return)
*cracked ceramic insulator (voltage leak/milliamp return)
*Bad Ground connection (electrode assembly mounting screw provides ground)

ECO....Hi Temp T-stat (Energy Cut Off)
Trips at 180*F if t-stat fails to open at 140*F
Locks out all heating attempts until reset
Reset by turning On/Off Switch(s) OFF then back ON after temp drops below 150*F ((temp ECO closes)
12VDC from Circuit board to/thru ECO to gas Valve on GAS
Millivolt DC from circuit board to/thru ECO to gas valve/ground on Electric (allows for ECO to be part of Temp control loop)

So was water VERY HOT then ECO opened/bad T-stat
Water was normal or just warm then Spark Electrode issue

2008 vintage....
New spark Electrode and set of t-stats inexpensive and worth changing out

Spark Electrode..... Atwood 93868 ($12/$15)
T-stat/ECO..... Atwood 91447 ($12/$15)
*Amazon pricing

pflightnut · 08-12-2022, 08:11 PM

My wife did say the water was extremely hot yesterday when she was doing dishes, so I guess the thermostat is going bad... I'll change the ECO/thermostat and the spark probe as suggested. What about the pilot ignition thermostat 91601 while I have the patient open for the procedure? And my next search is for a YouTube video of the disassembly...

Old-Biscuit · 08-12-2022, 08:40 PM

Quote:

Originally Posted by pflightnut

My wife did say the water was extremely hot yesterday when she was doing dishes, so I guess the thermostat is going bad... I'll change the ECO/thermostat and the spark probe as suggested. What about the pilot ignition thermostat 91601 while I have the patient open for the procedure? And my next search is for a YouTube video of the disassembly...

2008 Model with gas and electric.....would NOT have a pilot gas control unless someone swapped for an earlier version

Your 2008 combo WH should be a GC6AA-10E (6 gal) or GC10A-4E (10 gal) model.
*combo models since 2004 use common T-stat/ECO for both gas & electric

pflightnut · 08-12-2022, 09:10 PM

Old Biscuit - Thanks... the manual suddenly makes sense based on your reply. I believe I do have the GC10A-4E (I'm looking thru some old pics, and will pop the cover tomorrow to confirm). I watched a couple of videos and I just need to purchase the parts and the change out should go quickly. Thanks for your insights!

pflightnut · 08-28-2022, 06:18 PM

Sure enough, I have an Attwood GC10A-4E. I received the parts (ECO, thermostat, and spark thingy) and started the install yesterday. Got stuck on doing the ECO and thermostat...grrrr. Those metal tabs that are supposed to retain the plastic rim that retains the spring are making me crazy. I compress the spring, but even then the assembly is too thick to fit the spring and the plastic ring under the tabs. I've bent the tabs out slightly, and still no luck. I gave up after an hour of struggling, and will go back to it on a cool morning. It's just too hot and humid to wrestle with right now. Next trip isn't until mid-Nov, so I have a bit of time, and at least two other repairs to deal with.

If anyone has a tip on making the new parts fit, please chime in. I'm looking for a tool I saw in a You Tube video, sort of an L-shaped hook to rotate the plastic ring...

TIA,
Steve P

pflightnut · 09-04-2022, 07:14 AM

To those who do this repair in the future... first remove the aluminum heat shroud (two screws) for better access. And the fun begins...

Note that the plastic retaining ring and spring combined thickness barely fit under the 3 metal tabs. Carefully bend the tabs outward slightly between 30 and 40 (ish) degrees. Place the thermostat against the tank and slide it around to get the two ears under the metal housing and securely against the water heater tank. This helps stabilize the thermostat.

Start with the notch in the retaining ring at the top tab and rotate the ring in either direction so that it catches under the tab. Continue rotation in the same direction until the notch aligns with the next tab. Using a screwdriver, gently push the spring out of the way of the tab, and rotate the plastic ring so that it catches under the second tab. Now comes the hard part... carefully move the thermostat around to allow you to rotate the plastic ring just past the third tab. Again, gently push the spring away from the tab. Then, use two small thin screwdrivers, one on the edge of the ring, and one in the corner of the notch, to push down on the retaining ring and at the same time, rotate the ring under the tab toward the bottom of the thermostat. Stop rotating the ring when the notch is centered at the bottom of the thermostat, between the left and right tabs.

Place the foam gasket with the labels over the electric prongs, connect the wiring, replace the heat shroud, and you are finished.