Water heater problem

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8Muddypaws

8Muddypaws

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We have an Atwood GE16-EXT 10 gallon water heater.  When using the electric side it heats water for a while and then the lockout/fail light comes on and it shuts down.  Yesterday the popoff valve was triggered but the water in the tank did not seem to be anywhere near 200F but my IR thermometer may not be that accurate.

On this model Atwood there is only one set of thermostats.  At first I thought they were failing but when run on gas it works perfectly.  This led me to the SPDT relay on the (inaccessible) rear of the tank.

So I guess the only question I have is : does the lockout/fail light come on when the max temprature (ECO) is triggered?  If that is true I probably need to replace the relay and/or the control board.
Thanks for your advice.
Russ
 
Just a dumb question, but are you positive about your incoming power?  Seems to me that its possible high resistance is causing high current draw tripping the overload
 
No.  in fact a couple of other campers have made remarks about big voltage fluctuations in this park.  But we've been here dozens of times before and have never had a problem.  Would that cause the lockout/fail light to trip?

BTW, Thanks

 
A "lockout" is usually associated with LP gas mode (failure to light or sustain a flame), so not sure what your red light means. Do you have separate switches for LP and 120v mode? If yes, do both have a red light to indicate a problem? Usually the electric mode switch has either no light or a simple on/off indicator, but no fault condition.
 
Two there are TWO things on that model Atwood that can light the Fault light, technically 3 but if it's the 3rd water will NOT get hot ever.. (or the first for that matter)

One, As Gary pointed out, is lack of ignition in propane mode, or rather lack of ignition sense (Don't matter if it's lit, only matters control board knows it's lit.. My flame sensor chip got fried)

The 2nd,, IS an OPEN CIRCUIT on the ECO, this can happen two ways (The 2nd and 3rd options)
One the ECO opens due to overheate.. Two: You disconnected the RED wire from the ECO like a good boy when winterizing and did not connect... (Actually any break in the ECO circuit)

I'mf airly sure it's not the red wire

You said the TPO triped  was it drip drip or flood?  If it was a FLOOD (indicating high temp) the odds are teh main T-=Stat is flakey.
 
That's the part that has me confused.  It was a goodly stream of water and not a drip drip drip.  But if the thermostat was flakey it should be flakey for both electric and gas.  Right?  It's been operating on gas for 36 hours so far without a problem.  I have never removed a wire when winterizing.  But I do put a sign on the switch that turns on the Element to remind us that the tank is empty.

We're leaving on a multi month trip soon.  If I can't fix this fast I'm thinking I might buy a complete set of parts- (t-stats, control board, relay, element, sealer and caulk) to take along 'cause I know it will happen again at the worst possible time & place.  S'only money.
 
I think Russ knows all this, but I'll recap just to be sure:
The EXT models (and most all Atwood combo models since 2004) have a single thermostat that serves both gas and electric.  The electric-side control logic is simple: if the thermostat calls for heat, the board closes a 120v power relay that connects the source 120v to the heater element. It leaves it closed until the thermostat stops calling for heat.

Failure to heat on electric will be one of these:
1.Loss of 120v power on the circuit , e.g.an open breaker or broken wire
2.120v power relay fails to close
3. Burned out heater element
4.Faulty circuit board fails to activate the 120v relay

Sadly, the Atwood heater service manual gives no information about lockout conditions that might pertain to electric operation. However, since Russ's heater works well in LP gas mode we can rule out ECO, gas non-ignition, and other common components. Also, since the heater does at least one cycle on electric, the heater element must be ok. I think, though, that the heat from the tank could cause the board to malfunction(it opens or shorts when the board gets hot) o  the relay to malfunction.
 
Most Surburans have seperate T-States for Gas and Electric
MOST Atwoods have only one set used for both gas and Electric

Key word in both sentences is MOST..

But you have still described a bat T-Stat rather well, opening of the ECO will fire off the FAULT light and lock out operation same as no flame detect.  Over heat can also open the TPR's "T" valve.. On some of the TPR's that not resettable, others it auto resets, what you have I have no clue in this respect since I've never done it.
 
Looking at Gary's list for no hot water on electric and thinking through them backward, the most likely thing to cause the heater to not be shutting down when the water reaches the correct temperature would be the relay. The contacts could be welded together or the relay simply failed on the operated position. That's just my opinion, but relays aren't hard to check.
 
The Atwood manuals cover all of the different Atwood models.  Some with two thermostats and some with only one.  The manuals I have do not explicitly cover the GE16-EXT model so I had to operate from memory.  I had the water heater completely out about 6 months ago and almost recall what I saw.  (I should have taken pictures)

My conclusion is still that my problem is either the relay or the circuit board.  The board is $128 on amazon and is easy to get at but the relay is $16 and a giant PITA to get at. 

I find suburbans easier to work on.  All the important stuff is in the front.  ???

 
kdbgoat said:
Looking at Gary's list for no hot water on electric and thinking through them backward, the most likely thing to cause the heater to not be shutting down when the water reaches the correct temperature would be the relay. The contacts could be welded together or the relay simply failed on the operated position. That's just my opinion, but relays aren't hard to check.
Click to expand...

This one is.  The WH has to be removed to get at it.  I could probably do it by pulling the WH out a foot, but if I pull it out a foot it's just as easy to pull it all the way out.  Once empty it doesn't weigh much.
 
There is a 2007 Atwood Service Training Manual available from Adventure RV that covers several different Atwood appliances & models, including a section explicitly on EXT heaters. Not as helpful as it could be, but at least it speaks to the EXT. Section begins on Pg 37 in the Water Heater section

http://manuals.adventurerv.net/Atwood-Mobile-Service-Training-Manuals-2007.pdf

Note to others: This is a really comprehensive manual, covering Atwood products such as leveling jacks, ranges, thermostats, and furnaces, in addition to water heaters. Really good to have, though individual topics are somewhat hard to find within it.
 
Thanks for finding that Gary.  Not much information regarding my WH but the rest of the manual will come in handy.

It's going to stay like this for a couple of months. 
 
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