Next to last chapter on Atwood WH repair

[lsbrodsky]

I had reported that my WH was not working on electric, just fine on gas. Because I did not have 12v at the yellow solenoid wire, I replaced the board. Probably not that since I measured voltage with the coil energized, instead of open circuit.
So today I decided to replace the element and relay on the back. Now on my 25FB the only way to get to the back is to partially pull the WH and stick your head in the outside compartment. I would like to strangle the folks at AS who designed no access. There is a panel next to the bed that could have been removable but it is screwed in with no access to the screws, as long as the WH is installed.
Well, I found the culprit. The relay was toast, one load contact had melted and it also fried one of the solenoid contacts. The element resistance was infinite, open.
But, it took me 3.5 hours to remove the element with a CAMCO element wrench because I had no leverage, no ability to get in there with two hands. I could not pull the WH any further than the foam casing.
Finally, got that out, new element, new wiring, new relay. 9 AM to 4:30 PM.
If someone had come by and offered 25 cents for my trailer, they could have had it. Now I have to wait for some putty tape to put it back in and test it.
It worked on gas so if my labors did not fix electric, it is going to be gas only. I will never replace that element again. What a POS!!!

Larry

[lsbrodsky]

I buttoned up the system and ran a test and it still will not work on AC. The relay solenoid has the right resistance, 160 ohms, the old one had indeed shorted. There is AC power at the connections but the relay will not activate.
At the control board, with the harness disconnected, I measure 12 vdc at the yellow pin. But when I connect the harness, I am only measuring 0.7 volts at the harness connection.
I tried to get Dometic to tell me what this might indicate and they won't help consumers, referred me to service centers. My local RV service is a service center but does not have a board tester or any knowledge of the electronics.
I tried two other service centers and they do not know anything about the electronics.
I suppose the shorted relay solenoid could have damaged the electronics on the circuit board and it is the only thing left to replace, although these things are 100+ dollars. I wish I could find a schematic for the board. It still works fine on gas.
Larry

[SeaLevel]

Will you take.50 today?

Would it be easier to just replace the entire unit?

[lsbrodsky]

The stupid thing works on gas so it seems foolish to spend $700 on a new one and another two days to remove and install it. If I must go that route, I will just install an on-demand gas. I did like the AC ability, saving propane in campgrounds. But if I cannot get there, on-demand seems more useful. Yesterday was 25 cents, not sure about today....
Larry

[OTRA15]

Former thread is here FYI:

http://www.airforums.com/forums/f445...em-116948.html

[Foiled Again]

Check the circuit breaker / fuse in your converter?

[lsbrodsky]

Already did that. No problems. 12v at circuit board, 124v AC at junction box. But thanks.
Larry

[lsbrodsky]

I just heard from Airstream support and they told me that these days the little panel I mentioned is being installed as removable to gain access to the back of the water heater from inside the trailer. As I said on mine, it is pocket screwed fore and aft and no access to the screws. If I want to get in the back again, I will cut the screws with a Sawzall! Wish I had known that before yesterday...
Larry

[lsbrodsky]

I tried to get a warranty replacement on the board I put in the water heater. The internet vendor won't and insists that Atwood must. Atwood says return the board to vendor, who won't take it or have a local Atwood service center test the board and return it to Atwood. My local Atwood service center does not have a board tester and Atwood's answer to that is take the whole trailer to the service center, have them troubleshoot the whole thing, and if it is the board they can send it to Atwood. Of course I bought my board from an internet vendor. So this would be more costly than just buying another board.
Instead, I ordered a Dinosaur UIB64. Made in USA and warranted by the manufacturer regardless of vendor. If not that, I do not know what else. I am in water heater purgatory.
Larry

[windfallsp]

Originally Posted by lsbrodsky

I buttoned up the system and ran a test and it still will not work on AC. The relay solenoid has the right resistance, 160 ohms, the old one had indeed shorted. There is AC power at the connections but the relay will not activate.
At the control board, with the harness disconnected, I measure 12 vdc at the yellow pin. But when I connect the harness, I am only measuring 0.7 volts at the harness connection.
I tried to get Dometic to tell me what this might indicate and they won't help consumers, referred me to service centers. My local RV service is a service center but does not have a board tester or any knowledge of the electronics.
I tried two other service centers and they do not know anything about the electronics.
I suppose the shorted relay solenoid could have damaged the electronics on the circuit board and it is the only thing left to replace, although these things are 100+ dollars. I wish I could find a schematic for the board. It still works fine on gas.
Larry

Larry,

We had a similar issue with our Atwood hwh, but before trying a new element, we decided to try a new circuit board, which we were able to get for less than $100 from Amazon.

You'll need to know your model number (which we were able to find in the owner's manual that the PO of our 2001 LY moho had carefully preserved). With that number, you can find the part number for the circuit board.

The installation of the new circuit board was very easy and worked like a charm.

Good luck!

[lsbrodsky]

I replaced the circuit board first because some measurements indicated a fault. I might have fried the new one, don't know. But when that did not work, I pulled the water heater and found the relay burnt and the element open, infinite resistance. It could be that the shorted relay faulted the circuit board. I have replaced the relay and element and am awaiting a Dinosaur board to replace the Atwood board I think is bad. Should have it Saturday? Last hope

Larry

[Al and Missy]

This may help, or not....

Diagnosis is on page 11, A schematic for the a heater with AC operation is on page 23.

Atwood-Mobile-Service-Training-Manuals-2007.pdf

I think you are on the right track. The control board should be supplying 12V to the relay. The thermostat and cutout are common to gas and electric, I don't see any reason from the outside that the controller shouldn't be working.

Al

[lsbrodsky]

Thanks Al. The real puzzle is that with the harness disconnected there is 12v at the relay pin. But when I connect the harness and measure voltage on the yellow wire it is only .75v. So the 160 ohm relay coil should not drag the voltage down, it is not shorted, although the old relay was. I can only conclude that something in the board failed due to the shorted relay coil.

Larry

[bwoodtx]

On my 6 gallon Atwood that is gas/electric, there is a switch that activates the voltage to the relay through the circuit board. You could by-pass the circuit board and the relay and just wire it direct.

By the way, with all that being said-I opted to get a new water heater that is Gas/Electric without the electronics. Manual light for gas, straight 110v through the switch, all is good. Sometimes technology gets in the way. I don't mind having to go outside to light water heater-and if it is raining-I just flip the electric switch-plenty of hot water for two full showers.

BTW the water heater was under 400.00 from PPL motorhomes out of Houston, TX.

Good luck. Mine drove me stir crazy as well until I bit the bullet and went the way above.

[Al and Missy]

Originally Posted by lsbrodsky

Thanks Al. The real puzzle is that with the harness disconnected there is 12v at the relay pin. But when I connect the harness and measure voltage on the yellow wire it is only .75v. So the 160 ohm relay coil should not drag the voltage down, it is not shorted, although the old relay was. I can only conclude that something in the board failed due to the shorted relay coil.

Larry

It is quite possible that the relay driver circuit has failed such that it can only deliver a small amount of current to the load. At 12 volts, the coil would draw 75 mA. 0.75 volts across 160 ohms would indicate just under 5 mA of current. So it seems that the driver can only deliver that, and not the 75 mA necessary to actuate the relay.

This is a reasonable failure mode if the circuit was not designed to survive operating into a short.

Al

[lsbrodsky]

Thanks, Al that is good to know.

What brand and model of heater fits in there and is manual lp and AC? No electronics might be good...
Larry

[franklyfrank]

Originally Posted by lsbrodsky

I tried to get a warranty replacement on the board I put in the water heater. The internet vendor won't and insists that Atwood must. Atwood says return the board to vendor, who won't take it or have a local Atwood service center test the board and return it to Atwood. My local Atwood service center does not have a board tester and Atwood's answer to that is take the whole trailer to the service center, have them troubleshoot the whole thing, and if it is the board they can send it to Atwood. Of course I bought my board from an internet vendor. So this would be more costly than just buying another board.
Instead, I ordered a Dinosaur UIB64. Made in USA and warranted by the manufacturer regardless of vendor. If not that, I do not know what else. I am in water heater purgatory.
Larry

This won't help you solve your problem but it is germane to the thread.
Last year the Atwood water heater started leaking. After some effort I located the source it was a faulty weld of one of the fittings to the tank. It was very difficult to locate since I had remove the entire unit and than had to pressurize the tank. Contacted AS was told to contact Atwood. They said it was out of warranty. I told them it was a faulty weld, and it took me a year to finally find the source and it was your lousy workmanship. They would not relent. I was so cranked up about it I threw the WH in the truck and drove 3 hours to Elkheart. I stormed in there with the unit ,the supervisor took one
look and told the man I argued with over the phone to give this man a new unit. All together it took me three days but got my new Water heater. It was bitch to remove and reinstall.

[DDickey]

I'm so sorry. Problems like this can drive a good man insane, best of luck to you

[Al and Missy]

Larry,
I don't know the answer to your question. All current combination models appear to have a controller board. The LP versions with a pilot light instead of electronic ignition appear not to have a controller.

There is a process to test the controller board with a multimeter in the document I posted.

Al

[bwoodtx]

Originally Posted by lsbrodsky

Thanks, Al that is good to know.

What brand and model of heater fits in there and is manual lp and AC? No electronics might be good...
Larry

As I mentioned in Post #14, this is the water heater I went with.

80-1348
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Manufacturer #s: GC6AA-8, 96117 $357.50
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