Old-Biscuit
Across the USA
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Joined: 06/20/2009
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2007 Atwood water heater GC10A-4E
We FT and first 3 yrs. water heater worked great. Then after one travel day it wouldn't turn on (electric or gas). Found T-stat bad, replaced it. 1 1/2 yrs. later water heater wouldn't turn on. Again the T-stat was bad, replaced it. 6 months ago water heater quit again. Yep T-stat.
Replace it again.
Yesterday we leave central FL and drive up to gulf coast area. Water heater had been working great. Get up this AM and no hot water.
So I check AC power....still on
Flip on the LP Gas......nope won't even try
Pull connectors off circuit board.....check pins and clean contacts
Check 2A fuse on board....good
Jumper thermal fuse....still won't lit
Jumper ECO.....still won't lit
Jumper T-STAT......fires right up
Check across terminals on T-stat....switch is open (Tank is cold)
This water heater uses one set of T-stat & ECO for both electric and gas. It is mainly operated on electric (95%) with occasional gas.
Only problem ever has been with t-stats. This will be the 4th one in little over 5 yrs.
T-stat (and ECO) only have 12V DC to/thru them (AC function is done with a relay). Yes it gets a LOT of use......24/7/365
Replacing them is not hard BUT I don't know how many times you can bend the little tabs that hold T-stat tight against tank before they break off....and I know that will happen one day!
I just don't understand WHY the high T-stat failure rate. I PM'd a couple of individuals on here and they are stumped also.
So any ideas/suggestions/troubleshooting/things to test/check 
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Dusty R
Charlotte Michigan 48813
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Joined: 04/05/2003
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Perhaps the coil on the relay draws more power than the t-stat is made to handle.
I'm in Zephyrhills.
Dusty
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enblethen
Moses Lake, WA
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Joined: 01/05/2005
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I was thinking about your issue. I wonder if the small bi-metal thermostat just gets tired fast. Maybe one of these larger bodied adjustable thermostat would last longer.
12 volts going through the thermostat just to operate the electronics should not have much electrical load. It must be just the heat onto the bi-metal contatcs.
Atwood adjustable thermostat.
Bud
USAF Retired
Suzuki XL7 pushing Pace Arrow
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Old-Biscuit
Across the USA
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Joined: 06/20/2009
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Well,
After speaking with Atwood Tech. I did a little more troubleshooting.
Tech suspected 'high' AC Ripple could be causing failure of T-stat. (AC ripple is result of converting AC to DC...how much depends on diodes/capacitors).
DC voltage was constant at 12.5V DC
AC voltage was constant at 122V AC on LP Gas & 120V AC on electric
AC Ripple was measured at .4/.5 volts
So it looks like I have found 3 things......
1) AC Ripple is NOT excessive......little higher than I thought I would see
2) Converter is not going bad
3) Still DON'T know WHY the failure(s) of T-stat
Going to pick up an adjustable T-stat next week when closer to an RV parts store.
Still mulling over idea of in-line noise filter on 12V DC power to water heater?
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Old-Biscuit
Across the USA
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Joined: 06/20/2009
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