Water heater problem, need advice

[whit]

Hi guys,

Just got back from camping and had water heater issues. 1995 Bounder with Atwood water heater. Wouldn't fire, red light stayed on. Checked connections and thermostat lead broke off. Bought a ECO/Thermostat kit and replaced both. Still nothing worked. Checked for power throughout and have it to board connector. Cleaned and checked the ground and the main board contacts. Plugged it back in and it fired. Quit after about an hour. Unplugged the main connector and put it back, fired on again. This kept happening on and off for 2 days.
So I'm guessing the original board is bad. Thinking of putting a new Dinosaur board in. What do you think? Thanks!

[whit]

AC/Propane adapter kit?

[wa8yxm]

There are several options...

When the T-stat calls for heat the control board opens the gas valve and begins making sparks.. Around 1,000 volts of power on teh wire. After a few seconds of doing that it switches to heat sense and the thermocouple (Which may also be the spark "Prob" sends back just under 1/2 volt to the sensor chip.

Possible problems
Bad control not opening valve or not making sparks
Out of propane, bad reuglator, kink in line
Spark gap too wide (Actually fairly common) you can see and measure it without dissassembly so do so and comprare to owner's manual speciication.

Clogged gas jet (orifice)

Dirty flame sensor or bad flame sensor.

Bad connection flame sensor/ignition point to control board (kilo volt jumps it but half volt will not) (NOTE: you checked that alreday)

Bad control board not sensing voltage.

NOTE; that was in order of operation sequence,, I am not ipressed by the quality of construction on Atwood control boards, and Surburan uses the same boards.. I am seriously impressed by dinosaur boards.

You will need the AC/Propane adapter kit in all likelyhood, and do not forget covers.

[DaHose]

I had a similar problem and narrowed it down to a bad flame sensor or board. I started with the sensor, but the problem was the board. There went $30. That's almost half the cost of an $80 Dino board. From asking around I have gathered it very seldom is the sensor. If you test/suspect the board, change it.

Jose

[Old-Biscuit]

whit wrote:
Thanks for the info. No, flipping the switch off and on does not get it to refire only disconnecting and reconnecting, usually twice, the connector plug is the only thing that gets it to fire.
When I say that it works for an hour, I don't mean it heats constantly for an hour, I mean the red light stays off for an hour, sometimes 20 minutes, sometimes two hours. There's no rhyme or reason to how long it works normally and then quits completely and the red light comes on. When I replaced the new eco-and Thermo stat switches I made sure the tank was clean where they make contact, so I don't think they are the problem. Plus if that was the case then it probably would not work for an hour or two before the red light would come on.

Then test board........

[gatorcq]

Ignition/Sensor lead maybe bad or dirty. Clean with fine sand paper. Next Verify both the 12+ and - at the board. Final would be the the board since you changed out the ECO which contains a micro-fuse-temp

[whit]

Thanks for the info. No, flipping the switch off and on does not get it to refire only disconnecting and reconnecting, usually twice, the connector plug is the only thing that gets it to fire.
When I say that it works for an hour, I don't mean it heats constantly for an hour, I mean the red light stays off for an hour, sometimes 20 minutes, sometimes two hours. There's no rhyme or reason to how long it works normally and then quits completely and the red light comes on. When I replaced the new eco-and Thermo stat switches I made sure the tank was clean where they make contact, so I don't think they are the problem. Plus if that was the case then it probably would not work for an hour or two before the red light would come on.

[Old-Biscuit]

Just a few things........

WH heats water then shuts down & won't refire (fault light ON)

IF you turn ON/OFF switch OFF then back ON...will it refire?

Heating for approx. an hour is a long time to heat........HOW HOT is water heating too?
Normal t-stat should OPEN (shutting off heating) at ~140*F
ECO t-stat should OPEN at ~180*F IF normal fails to OPEN
IF ECO OPENS.......FAULT light comes on.....no reheating can occur until Fault light is reset (Switch turned OFF then back ON) AND water temp has cooled down below t-stat set points.

Unplugging edge connector on circuit board resets system.

SO........
Could be normal t-stat failure (ECO operating) Understand you replaced both t-stats but if normal is NOT making good/clean contact with tank surface it will not sense correct tank/water temp
OR
bad 'track' on circuit board.

Potted Board can be tested using multimeter set to ohms.....disconnect and remove for testing
Power track....Green wire contact on edge connector/black lead & Brown wire contact on edge connector/Red lead-----No continuity/bad track
Valve track......Green wire contact on edge connector/black lead & Blue wire contact on edge connector/Red lead--------No continuity/bad track

Non-potted board....disconnect/turn over and visually look for burnt/non complete tracks

[Gjac]

Mike there is a ground that is hard to see coming from the gas valve to the gas valve bracket. When you remove the nut to clean it be careful that you don't twist that ground wire out of the gas valve(I already made that mistake so you don't have to). I fought with my water heater for a while before I saw that ground. I am not sure but I think it was a green wire. Good luck.

[whit]

Thanks Richard
I know exactly what you're talking about.
The contacts look good and so does the contacts on the circuitboard, nice and clean, however I will get a dental pick in there and bow them up a little bit more to make sure that's not the problem.
That was in fact my only question about this whole thing. Was it the connector or the circuitboard?
I think I pretty much narrowed it down to one or the other. Doing what you suggested will help rule out the female connector.

[RLS7201]

Mike, Look at the circuit board plug-in connector more closely. Those contacts are supposed to be bowed. They sometimes loose their tension and go flat and need to be re-bowed with a dental pick. I learned that the hard way on my 95 Bounder with Atwood water heater.

Richard

[whit]

Yes, I cleaned the ground and the circuit board contacts.
I also checked the circuit board plug to make sure there is nothing wrong with it
What I mean when it shuts off, the red light comes on and it stops working again.
Until I go outside and unplug and replug the main board connector then it immediately fires and works for a random short time. But eventually the red light comes back on.

[Gjac]

whit wrote:
Thanks,
It's the original board. I wonder if I remove it and take it to my local RV dealer if they could test it for me? I will call them tomorrow and ask.
I was just wondering what you guys thought of the symptoms?

If you have a multi meter you can do this your self in 5 mins. I think just by removing it you will clean the contacts and that might help you. If you haven't cleaned all the grounds and other contacts do that also. You say that it stays on for an hr then shuts off. This sounds like the water is being heated and it has reached the temperature of the thermostat and is being shut off(normal).

[whit]

Thanks,
It's the original board. I wonder if I remove it and take it to my local RV dealer if they could test it for me? I will call them tomorrow and ask.
I was just wondering what you guys thought of the symptoms?

[Gjac]

Mike if you go to the Atwood web site or manual if you have one it tells you how to test the board and other systems of the water heater just using a multimeter. You probably have a potted board if it is original and can't see the components inside if someone replaced it at some point it will be just a board with soldered components, you can look at the back side to see if any components are burned or any arcing in the tracks.