Heat, I need heat

[bsmith0404]

Originally Posted by JBM3M

Did the power cycle for 5 mins off and re connected.


Battery or shore power problems are the same.


Accessed the one and only side of the unit that I can without taking the unit out. Opened it up in the inspection hatch and only can see the heat exchanger.

Also do have gas to the unit.

Owners manual says something about control board lights, cannot see at this point. Looked in owners manual for location of sail switch, it shows wrong side related to what orientation I can.

From my experience, it’s much easier to disconnect the vent hoses and pull the unit to a point where you can access everything. The sail switch is near the blower. On mine its on the right side as you’re looking at the exhaust port.

[bsmith0404]

Originally Posted by KenSC

As far as using heater, mine has an option to use electric heat as a source from the air conditioner vents. Not sure if all RV's have this option but if so that might be better than running a space heater.

Heat pumps are not included on all RVs, typically only on Luxury models such as Alpine and Montana. If I remember correctly, they started making them available on High Country back around 2020 as well.

[JBM3M]

My blower is on left looking at exhaust and I am pretty sure that is where the switch is. I will have to disconnect the exhaust which is attached to the exterior wall from the looks of it. I would like to know how the heck they got it in there....lol. It will have to wait until we get home, not going to tackle that when out camping.

[bsmith0404]

Originally Posted by JBM3M

My blower is on left looking at exhaust and I am pretty sure that is where the switch is. I will have to disconnect the exhaust which is attached to the exterior wall from the looks of it. I would like to know how the heck they got it in there....lol. It will have to wait until we get home, not going to tackle that when out camping.

They put them in before everything else, including the floor decking. Mine was a lot of fun, I had to cut the drain line for the washer in order to get it out. I have a rubber repair coupler on the drain line now so it’ll be easier if I ever have to pull it again.

[JBM3M]

fortunately I don't have a washer, lol.


It won't be fun, that is for sure. I wonder if a mirror in the compartment would do the trick....from those of you who have had to do this.

[bsmith0404]

Originally Posted by JBM3M

fortunately I don't have a washer, lol.


It won't be fun, that is for sure. I wonder if a mirror in the compartment would do the trick....from those of you who have had to do this.

I pulled the panel under the steps as well as the basement wall so I could access both sides. It definitely helped having a drop frame with a huge pass through, I wouldn’t want to work in a regular pass through.

[JBM3M]

Okie dokie, got the unit turned in the space where I can see the goodies. The board error code after a failure (without gas hooked up) is 3 blinks followed by 3 sec pause. According to the label that means "Ignition lock out fault."


I removed the sail switch, it is fine, no dirt and ohmmeter says conduction. I get a single tap noise, 3 times before it gives up, but not the typical tap,tap, tap, tap noise of ignition. What I believe to be the solenoid on the board makes no noise or has no sensation of anything when I get the single tap. Even that doesn't sound typical.


Now, on the internet I found some guy who says it could be this sensor. The one with the blue wires going to it. Little round thing, at this point can't get my hand in there and will have to do a lot of teardown to get at it. So I haven't tested if the terminals by shorting across them to close the circuit. (he said it was safe to do)




So wise ones, what say you now? Board or that sensor or none of the above. As always, thanks in advance.

[jasin1]

Originally Posted by JBM3M

Okie dokie, got the unit turned in the space where I can see the goodies. The board error code after a failure (without gas hooked up) is 3 blinks followed by 3 sec pause. According to the label that means "Ignition lock out fault."


I removed the sail switch, it is fine, no dirt and ohmmeter says conduction. I get a single tap noise, 3 times before it gives up, but not the typical tap,tap, tap, tap noise of ignition. What I believe to be the solenoid on the board makes no noise or has no sensation of anything when I get the single tap. Even that doesn't sound typical.


Now, on the internet I found some guy who says it could be this sensor. The one with the blue wires going to it. Little round thing, at this point can't get my hand in there and will have to do a lot of teardown to get at it. So I haven't tested if the terminals by shorting across them to close the circuit. (he said it was safe to do)Attachment 42075




So wise ones, what say you now? Board or that sensor or none of the above. As always, thanks in advance.

here’s a service manual for suburban rv furnaces…look at the sequence of operation section and troubleshooting section https://manuals.heartlandowners.org/...11-05-2015.pdf

[JBM3M]

Well it its an Atwood AFMD35, not sure if same.

[jasin1]

Originally Posted by JBM3M

Well it its an Atwood AFMD35, not sure if same.

try this then https://myrvworks.com/wp-content/upl...ing-Manual.pdf

[jsb5717]

My experience with the sensor on our Atwood had our furnace firing and burning, then shutting off. That's different than your scenario. I'm not saying it couldn't be that sensor but our bad sensor allowed the furnace to ignite first. I've replaced that little round sensor and furnace now stays lit. I now also have an additional sensor for next time.

I also have a backup main board, which also contains the ignitor. They are easy to swap out and, if you had one, could tell you if that's the issue.

I'm not really an advocate of just throwing new parts at something as a means of troubleshooting, but you do have to weigh the cost of parts against the cost of a mobile tech with equipment to test such things. However, since I've had more components fail in this relatively new trailer than in all of my previous trailers combined that were typically 20 years old when I sold them, I've collected several such items for 'just in case'. Sadly, parts that never failed in older rigs seem to be dropping like flies. When I'm camping I don't what to have to wait multiple days to get a part that shouldn't have failed this quickly to begin with.

I believe your blinking light is a generic fault that basically says we tried to light 3 times and failed. It still sounds like a Sail Switch to me but if you're convinced that you've checked it correctly and that it's OK, then I'd suspect the main board.

FWIW, I'd be temped to test the sail switch while installed. Engage the furnace and, using a meter, see if the switch is actually closing and making contact.

[JBM3M]

Yes, removed the sail switch and checked with ohmmeter. Good conductivity and clearance for the "sail", no dirt. If it was the sail switch I should get a different error code. I.E. one blink every 3 seconds. The limit switch is apparently in the same circuit in series, so that rules that out too. I think it is the control board now. That first tick is probably the gas valve opening. It is not the igniter. These control boards seem pretty universal too.

[jsb5717]

The boards are fairly generic. Personally, I would shop for a replacement by Dinosaur Electronics rather than OEM. It's a better built board and is also what I have as a backup.

[JBM3M]

Originally Posted by jsb5717

I'm not really an advocate of just throwing new parts at something as a means of troubleshooting, but you do have to weigh the cost of parts against the cost of a mobile tech with equipment to test such things.

I agree, but the cost of any of the items is far less than just the service call, plus minimum of 1 hour labor for the folks I use.



$150 for a board is less than the service call, much less labor and such.
Hey at least we got rain and the smoke is gone

[sourdough]

3 blinks, pause, 3 blinks.....that's what mine was doing when I had to replace the control board.

[JBM3M]

Amazon can have me one by tomorrow for $100 with tax and shipping

[jasin1]

you very well may be right about the circuit board but why not test everything first? the service manual has step by step instructions… even something as simple as a loose ground wire at the furnace can allow the blower to work but no spark ignition…i dunno i would just check everything first

[JBM3M]

nothing left to test.

[jasin1]

Originally Posted by JBM3M

nothing left to test.

right….ok…good luck …you may get lucky with the diagnosis but it’s just a guess

[JBM3M]

Originally Posted by jasin1

right….ok…good luck …you may get lucky with the diagnosis but it’s just luck

I don't believe in "luck" for repairs. I don't just order parts. The sail switch and the limit switch check out with ohmmeter, the gas valve opens and that is the end of function. I cannot locate how to test the board itself, got a link?
So tho not proven this is an educated guess via rule outs.