Troubleshooting Atwood/Dometic furnace repair walk through tear down part 3

Here I take the furnace apart right down to the high limit switch. I will get better quality video as I get more into this. Please subscribe and like so I can launch this and help you all with videos like this. Thanks.
• Troubleshooting Atwood... part1
• Troubleshooting Atwood... part2
• Troubleshooting Atwood... part3
• Troubleshooting Atwood... part4
Repair Parts:
Controle Board: amzn.to/2OmwvIB
dinosaur universal furnace fan50Plus board: amzn.to/31kCaED
basic tstat: amzn.to/2OnI2aD
new style tstat: amzn.to/2tntUHc
blower motor: amzn.to/2RVxXn
analog tstat: amzn.to/2udZyaC
5button CCC: amzn.to/2UjACcl
sail switch Small: amzn.to/2UltUm4
burner: amzn.to/2SdYkEk
limit switch: amzn.to/2RR3Du9
combustion wheel: amzn.to/2Sf5LuO
blower wheel: amzn.to/2UkyAsD
electrode: amzn.to/3b3Sf5T
8500 sail switch: amzn.to/2RQDEDa
sail switch medium to large: amzn.to/2GQGeml
Tools I use:
olfa knife- amzn.to/2LfQsPZ
drill bits- amzn.to/2PfP4Oi
angle grinder- amzn.to/384b8nP
1/2 impact gun- amzn.to/2sIWQZE
scissors- amzn.to/34NnxdP
step bits- amzn.to/2DFqLUG
heated coat- amzn.to/361wwZ6
hammer bits- amzn.to/2Rgd72o
m12 die grinder- amzn.to/2ONFALg
replacement filter for milwaukee vacuum- amzn.to/2YeQUDf
Vacuum milwaukee- amzn.to/33P51QO
Drill- amzn.to/2qjG0Qf
1/4" impact- amzn.to/2r23pGl
osculating tool- amzn.to/2DKM87b
Driver Bits- amzn.to/34O2Y0T
Markers- amzn.to/2YfCy5F
Extension- amzn.to/389wujx
step bits- amzn.to/366eoNQ
18" pipe wrench- amzn.to/2OMrEB8
pipe cutter- amzn.to/361JUwg
flaring tool- amzn.to/2OOoBIC
pipe threader- amzn.to/2YhQwE0
vacuum detail kit ridgid shop vac- amzn.to/2PekW61
copper cleaning brush- amzn.to/2YjMZoA
hepa filter ridgid shop vac- amzn.to/386PWO2
plastic pipe cutter- amzn.to/2LnMKUw

[@raymondherbst7126]

Nice looking at your shoes.

[@jcobra09]

Literally the only video I can find to pull the sail switch on this model. I’m cleaning mine. Thanks man

[@thecanadianrvrepairguy3062]

No worries guess I should do some more of these videos.

[@LTVoyager]

Sure would be easier to follow if the camera wasn’t sideways.

[@vincentgonzales8917]

Just finished repairing 8535-IV atwood after watching you video. The part I was missing was where does the blue wire from the reset switch go and what was the other blue wire doing. There was nothing turning on except the temperature at the thermostat. Turned out to be a loose wire there.

[@Jimmy09Melton]

I have the atwood with the attached gas line. How do you get that out?

[@bullfrog54]

My Atwood 8940 III DCLP starts, ignites, lights and runs for a few seconds then repeats until lockout. I've checked, limit switch, sail switch and igniter, all check good. I could really use some insight of what to check next. Only light flashes I get are when it locks out.

[@thecanadianrvrepairguy3062]

It could be the board or the ignitor not seeing the flame. Is the ceramic around the ignitor cracked or damaged

[@racingromeo28]

I have this exact same furnace in my coachman camper.. All it does is make a click when its turned on. But no blower operation what so ever.. Ive already replaced the sail switch and circuit board. Still no operation. So I tore back in it and removed the blower motor, hoping that was the culprit.I hooked the motor up to a power source and it operates normally. Any ideas?

[@saskdad115]

Did you get this figured out? I am experiencing the exact same symptoms and need to figure it out.

[@jasonfreeman6662]

Yea I did. Finally figured out that the previous owner had 2 wires plugged into the circuit board backwards. Then the blower would run and click but never light. Had to replace the igniter. Works great now

[@stangeorge2791]

Thank you for the great videos I have learned a lot from them. I still have a problem with my Atwood furnace (AFMD30111) not running. 1. No led light on board 2. replaced with new board and no change 3. Fan motor will not kick in at all 4. have power to on-off switch and through switch 5. thermostat is set to furnace and calling for heat but I have nothing. This furnace worked last year but not this year. Any help would be appreciated.

[@thecanadianrvrepairguy3062]

Glad you enjoyed the video. As far as your issue check to see if there is power to the blower motor if there is than that’s your issue if not then would need to test the sail switch and limit switch see if power is running through there.

[@ronniewetherington509]

Thank you very much for taking the time to share.

[@thecanadianrvrepairguy3062]

My pleasure!

[@lynseyiriz]

I am trying to troubleshoot my issue. And maybe you can suggest something..tried new thermostat, and new board.. issue. Thermostat off, runs, blows heat, won't shut off. Doesn't seem to be a crossed wire. I have air and heat. Currently only have red, white, green hooked up. Stove lights, no flickering. My furnace just wants to blow heat, all the time. I'd appreciate any suggestions

[@thecanadianrvrepairguy3062]

What model of furnace

[@lynseyiriz]

@@thecanadianrvrepairguy3062 thank you, I moved. Not sure...

[@jamiedeters5454]

We have an Atwood RV furnace and it started not staying ignited. We are getting 3 flashes from the boards red indicator light at 3 second intervals. Any ideas what to check first?

[@thecanadianrvrepairguy3062]

That is a high limit code.

[@jamiedeters447]

How to fix it is in the video, correct?

[@JohnNguyen-iw8qn]

Now how do you remove that red pinch ring without the furnace pulled? Atwood is made to be serviceable from the front of the unit I thought including the wheel... But I haven't been able to get that dang ring undone without braking a blade.

[@JohnNguyen-iw8qn]

@The Canadian RV Repair Guy thoughts?

[@thecanadianrvrepairguy3062]

I have a long pair of needle nose pliers with a 90 at the tip. That’s how I get it out.

[@JohnNguyen-iw8qn]

Hmm perhaps that's the trick having a right angle on there. My straight needles just slips off. Thanks!

[@sarahhewlett2366]

Information is awesome!!! Camera work is terrible. You should get a friend or a tripod!

[@paulmccarthy123]

Thank you so much. I have the exact same model 8531-IV and I was getting all the normal steps in the process (blower, three attempts at lighting) then getting the lockout code with three blinks. I figured it was a bad igniter, but noticed that the connector spade that hooked to the igniter looked pretty rusty. With your directions I was able to pull it out, clean off the connectors, and then put it back in - presto! Works great now. The burner head looked pretty rusted out so I’m ordering a new one of those, but I’m so happy to have fixed this so easily with your help. Thanks.

[@thecanadianrvrepairguy3062]

Glad it helped.

[@qbert008]

I removed the furnace from my TT and could not figure out it came apart. Then watched your videos 1-3, and in 10 min dismantled and diagnosed the issue. Temp issue resolved (burner melted and carbonized) and new part on the way. Thanks! And subscribed.

[@brianross1469]

I have a 1 year old Atwood furnace. Blower will not start, . I have 12 volts to the circuit board but nothing happens. I through 90 dollars at it and replaced the board. Any thoughts on what I should check next? I also here a click when I set the digital thermostat, so I assume it is working fine. Thanks!

[@thecanadianrvrepairguy3062]

If you replaced the board I would put power to the blower motor directly make sure it runs then can narrow the search.

[@brianross1469]

@@thecanadianrvrepairguy3062 Thanks for your help!

[@saskdad115]

Did you find the problem and get it fixed? I have the same issue and need to diagnose

[@MrAustin602]

Thanks a bunch for all the information!!! Do you think you could ever run the furnace with blowing the heat? Not running the blower? It turns up my battery power. Thanks!!!

[@ifoleyienationchannel4779]

This video is exactly what I’ve been needing and looking for. Thank you so much for making it. It gives me hope and confidence to solve my problem.

[@thecanadianrvrepairguy3062]

Glad I could help.

[@bmicker]

Excellent video... Very informative!!!

[@biggusnikkus4401]

The best tutorial I have watched. Thanks you very much for your uploads.

[@skykid2]

Thank you so much for this video it's the only one I found on KZbin for the complete teardown... I bought a fifth wheel from 1999 and it had never been serviced the heat worked just fine until it got to 28° and then there was unburnt fuel. With your tear down I realized that the igniter ceramic part had a bunch of hornets nest or something that was leaving dirt in there vacuumed it out and hopefully that works

[@craigcarman354]

Thanks for your demo. Just what I needed.

[@threejtr5317]

I've spent likely 10 hours looking for info on KZbin and forums to help with my atwood 2334 2 Stage furnace issues. No surprise a fellow albertan I finally found has saved my bacon. Thank you so much for these 4 videos. My question. I'm waiting for new motor for mine but during disassembly my issue was a siezed exhaust (draft shield) atwood calls it. Tried wd40, pb blaster, nothing worked. I was forced to cut the shiny tin off the end of it so I could remove gas valve etc including combustion wheel, which then allowed motor removal. Then I could grab with pipewrench and finally remove. Big problem now is the exhaust ass'y is n/a, anywhere I've searched. Any idea? If I was to extend the pipe a little so that it protrudes out far enough to clear the metal cover would that prevent backfire risk that you mentioned on one of your videos. Sorry for longstory. Any ideas would be appreciated and thanks again fot the great simple to understand information. For all the audio complainers in comments , use closed caption.

[@DunMoreDennis]

Thank you Repair Guy. I can't believe I need to rip this thing totally apart to change out the limit switch which my board tells me I need to do. Bad design!

[@claudius622]

Very informative vidéo !!! Do you have any infos concerning the motor trouble shooting with the ohmmeter ? How many ohms between red and black and red and gnd and black and gnd ? Also how many starting and running amps ? Thank you !

[@robertviens9861]

Great video, very helpful and understandable. The blower wheel on my Atwood disintegrated for apparently no reason. I expected to see a mouse or something when I took the furnace apart but there was nothing but broken plastic. I replaced the wheel and still no heat. I noticed the sail switch paddle was bent and pointing straight probably from a result of the wheel disintegrating. Bent that back. So now I was it would fire up but would cycle on and off every 15-20 seconds.Checked the sail switch and the limit switch all was fine. This has been going on for 2 days now. I am about ready to throw this furnace out the window. I had watched part 1 and 2 and decided to watch part 3. One comment that cured all my problems. "make sure you put the exhaust back on" OMG it was like I just had an epiphany LOL. Ran back outside put the exhaust back on and there was heat. Thank you saved me from having someone else work on it.

[@thecanadianrvrepairguy3062]

robert viens. Thanks tried to be as informative as possible.

[@thecanadianrvrepairguy3062]

Always tri to be as informative as possible

[@theGMPconsultant]

Our Atwood 30131 furnace seems to work ok but the smell of the exhaust outside is atrocious and overwhelming. What do you think the issue is?

[@thecanadianrvrepairguy3062]

Might be a dirty burner or jet. Or could be LP pressure not correct.

[@MechanaholicsCreations]

Please help! I have a 8940-lll-dclp and it turns on and ignites and it will only stay lit for 1 to 3 seconds then stops the flame, then repeats. I've been living in this rv for 2 years and haven't had any heat. Been sleeping in 35 degrees and I'm so tired of it. Any help would be greatly appreciated!

[@thecanadianrvrepairguy3062]

It could be the flame sense or the board

[@MechanaholicsCreations]

@@thecanadianrvrepairguy3062 that's what I was thinking so the flame sense is built into the ignitor? The light never blinks during this whole process so it makes me think its the control board. But if it's not detecting flame would it blink?

[@thecanadianrvrepairguy3062]

Flame sense and Ignitor are the same thing. Yes it could be the board. It’s hard to say without testing

[@scottthomson6895]

Holy smokes. Thank you so much!!! My furnace works fine but the plastic blower wheel had some pieces break off. Because of that it was out of balance so the motor bracket broke: the 3 tabs that hold the bracket to the frame. So it sounded terrible and I had to shut it down. I couldn't figure out how to get the gas valve/igniter off so I could get to the screws to replace the mount. I got a new motor and a metal blower wheel but couldn't put the new stuff in. Your video saved me from having to get someone out to do the work for me (at $125/hr!) You, my friend, are a lifesaver!

[@thecanadianrvrepairguy3062]

Glad I was able to help.

[@aaronklein1490]

Do you happen to have any idea or tips on how to identify exactly which model of heater i might have? I have been able to get as far as being pretty sure it's at 8525 but I don't know if it's ii iii or iv honestly and I'm looking to buy a new motor for mine. Or would it matter even? The serial info seems to have work off on the black cover and it has me at a loss

[@thecanadianrvrepairguy3062]

Should not matter for the blower motor the iv incorporated some plastic parts in the blower housing to make it quieter

[@aaronklein1490]

@@thecanadianrvrepairguy3062 thanks for the reply. I got ahold of what was supposed to be the motor for my unit and got it installed but I suspect they may have sent a motor that's drawing a bit more power as the breaker switch pops after running and igniting perfectly for some time. I have to wonder of there's a danger in running the possibly stronger motor with a sutable breaker switch.

[@artamus73]

Great information!! This 3rd part dont come up as a suggestion on youtube after part 2 because the name is different, makes it tough for someone with no skill to find this 3rd video. Thanks for the info!!

[@thecanadianrvrepairguy3062]

Noted!

[@mgplaskett]

Great job! I will have no problem fixing my 8535II. Thank you for taking the time to help everyone that wants to repair their own units .

[@smitty522]

So I got a problem with mine it’s firing up however it’s not reading the flame I have replaced all the parts except for the board which the flame sensing an igniter is on could that be my problem?

[@thecanadianrvrepairguy3062]

Yes I would say a board issue

[@smitty522]

@@thecanadianrvrepairguy3062 Yeah so I finally got the board and put it in and guess what that’s exactly what it was I replace the entire proving system except for the board and that’s what it end up being the board anyway thank you

[@JustSomeGuy641]

Bought a fish house last year with this same furnace used it all last season for 3 1/2 months trouble free. Got it out on the ice this season it worked fine for two days. Then the blower started for 10 or so seconds but didn't ignite. Called dometic and they said it was probably the sail switch.. Took it to a local rv dealer they ripped it apart and said there was a big ball of lint on the sail switch they cleaned it cycled it a few times and it worked fine. Get it back out on the ice have heat for about 6 hours then boom DOING THE EXACT SAME THING! So I have to rip out my range again to get to it and save labor costs. I am at witts end with this thing its literally had less than 4 months of use. In my opinion the furnace design is total garbage. Was 100$ to fix it the first time now I have to do it all over again. And spend even more money! By the time it gets fixed i'd be well on my way to buying a new one. I asked the tech if he can just wire the sail switch together so I don't have to deal with the pos but he said he cant do it. Very very very disappointed in this model!

[@thecanadianrvrepairguy3062]

Just had a thought if you would like to send the unit to me I could do a video on it and do a complete service at a fraction of the cost of you taking it in.

[@wattyd6867]

I just came across your video!! Ironically I have a furnace issue, we own a 2016 keystone outback 326RL. The furnace makes this god awful finding banhing noise, I'm sure its the motor. Any other ideas you may have woukd be appreciated. Woukd you know if its a difficult removal, I have taken other furnaces out that were fairly easy. Last question are you close to Kamloops BC? Thanks

[@thecanadianrvrepairguy3062]

Sounds like the blower wheel is broken. No I am I. Alberta

[@wattyd6867]

@@thecanadianrvrepairguy3062 your bang on, I pulled it out today the little mouse destroyed the squirrel cage..

[@christinalipscomb8543]

@@wattyd6867 I belive I have the same issue. But I'm trying to figure out how to get the furnace out to take it apart.

[@wattyd6867]

@@christinalipscomb8543 is your furnace located in the pantry?

[@wattyd6867]

@@christinalipscomb8543 I should ask do you have the same trailer as I have?

[@joshbalogh86]

I can’t thank you enough for making these videos. I really appreciate it. I have an Atwood and heater stopped worked and of course it’s winter time and I live in my RV. The original board was flashing the limit switch one blink light. I replaced the sail switch and upgraded the board to the dinosaur fan 50. Still no clicking or heat. I checked the sail switch with a voltmeter and it seems to work. If the sail switch and limit switch are in series, do I need to pull my furnace apart to test the limit switch separately? What should I do? Thanks for your help

[@thecanadianrvrepairguy3062]

As long as you are using the correct wires there is no need to take it all apart to test the limit switch follow the wires and you will see where you need to test.

[@joshbalogh86]

Thanks again for your help

[@joshbalogh86]

I wanted to ask you what you think I should check next, I was wondering if maybe the electric solenoid switch went out, that’s not letting the gas to ignite, I still don’t hear the clicking sound before the flame. Thanks

[@thecanadianrvrepairguy3062]

@@joshbalogh86 at this point a phone or FaceTime consult I think might help you more. $50 through PayPal and attach you number in the comments and I can go over a few things with you to check while you do it.

[@Metabo1950]

You need a friend to do the camera work, I had to stop watching.

[@duanepeterson3849]

I’m getting a sore neck trying to watch this.

[@caroljohnson8817]

This really helps me a whole lot. My unit is fairly new, and the sail switch looks perfect. Now I know where the limit switch is. Getting to the limit sure looks involved though. Would it help me to,just pull the whole heater housing out? Maybe the fan cage is dirty? I’m Getting the one light indicator blinking.

[@CaptainHuKTv]

Great breakdown video bro thank you for the knowledge!

[@thecanadianrvrepairguy3062]

Glad I could help.