Community Forums

z3406 · 09-14-2019, 06:07 AM

I've also had this issue and know the reason. Water is getting into the furnace itself and puddling under the circuit board as another poster has mentioned. This causes the blower to run by itself, the heating circuit is not involved, only the blower motor running. This issue is so prevalent that Atwood has a circuit board relocation bracket now to keep the board out of the water if it gets into the furnace. They also have a revised door gasket to help keep the water out. I've had the mystery furnace running twice now both times after very heavy rains, the first time when I removed the outside air vent on the furnace the furnace stopped running, I suspect removing the vent broke the seal that was puddling the water and let the blower shut off. The second time was at a rally where an Atwood/Dometic rep was present and he informed me of the water intrusion issue, installed one of the stand off kits and replaced the circuit board which got fried the second time it got inundated. You could see arc marks below the circuit board main electrical connections the second time.
FWIW
The first time this issue happened was the first weekend out with this new coach so it isn't restricted to older furnaces but is an ongoing Atwood/Dometic issue.

Waiter21 · 09-14-2019, 09:01 AM

Mine actually calls for heat, the furnaces attempt to light even though I have the propane turned off.

I had to unplug the heater controls plug from the intellecc controller so the furnaces wouldn't attempt to light.

coop2.0 · 09-14-2019, 09:39 AM

I talked to intellitec yesterday and was told that it’s the thermostat itself and it’s happened all to often. They want it and module sent to them for rebuild at a cost of about 4 to 5 hundred. Unreal amount I have 2 issues the high limit switch and this thermostat ( which I can’t find anywhere). I just don’t know what I’m going to do. They want 95.00 to diagnose and 399.00 to rebuild. Has to be a better way to get this problem solved!!!!!

Waiter21 · 09-14-2019, 12:45 PM

Yah, I hate to spend $500 and in a couple years face the same problem....

I'm moving forward with my controller project.. Stay tuned

coop2.0 · 09-14-2019, 09:14 PM

Trust me I will be watching daily

coop2.0 · 09-15-2019, 04:10 PM

Ok so I changed the high limit switch even though it tested the same as the new one for continuity. But it still doesn’t work. Blower comes on but that’s it! On a good note it appears that the coming on by itself is over must have reset itself I hope. I took all duct work off and there was absolutely no air flow restrictions at all so what do I do now??? Just to clear things up, I turn on heat then slide thermostat up to highest setting, blower comes on but then after a minute it shuts off and gives a single flash then the 3 sec pause then flash......

coop2.0 · 09-15-2019, 07:09 PM

Ok well who said owning and rv was all bells and whistles and R&R. I learned something when the single flash and 3 second pause means Air Flow/ Limit Fault which could be 3 things.
Poor air circulation
Faulty High Limit Switch
Sail Switch
In this case as stated changed the high limit and had same problem so I bypassed the sail switch and furnace fired immediately, so I took motor cover back off and even though the sail switch looked clean I blew it off with compressor reinstalled it and it worked perfect. As for why the blower was coming on by itself is still a mystery and who knows may check later and it’s blowing again. As far as Intellitec is concerned I’m not sure I will ever trust them. Hopefully this ends the Ghostly Furnace Saga.

coop2.0 · 09-15-2019, 07:11 PM

Oh and Waiter21 I will still be waiting to see your progress and hopefully success as I will follow this post.

Waiter21 · 09-18-2019, 01:40 PM

Got the temperature sensors and control relays hooked up and the software is almost complete. Waiting for the current sensors to show up so I can test them.

Might be able to install it this weekend.

Rushy · 09-19-2019, 06:18 PM

I'm throwing in the towel for now. My last question (until spring) is how do I disconnect the furnace, if I pull the fuse I lose fridge, range hood and HW too. For now i found a switch that will turn if off but have to remove the outside panel to get to it. Suggestions?

Waiter21 · 09-19-2019, 07:08 PM

Unplug it from the controller board, it will be the plug on the left side of this photo, that is for both the front and rear furnaces.

Other than that, you could turn it off outside.

randyxa · 09-20-2019, 06:51 AM

Quote:

Originally Posted by Rushy

I'm throwing in the towel for now. My last question (until spring) is how do I disconnect the furnace, if I pull the fuse I lose fridge, range hood and HW too. For now i found a switch that will turn if off but have to remove the outside panel to get to it. Suggestions?

On my 2000 Pace Arrow, the furnace has an external (master?) on/off switch, take off the furnace cover panel on the outside of your RV and take a look, mine was near the igniter.
I am having the same issues with the intellitec system, hoping Waiter comes up with a good workaround.

coop2.0 · 09-20-2019, 08:06 AM

Rushy, The switch on the furnace itself is the best way . I did it for couple weeks until The ECC reset itself somehow through all the unplugging cleaning and so on. If you read my posts, somewhere in all that I did it works fine now but have no idea what actually done it!!!!