Small vent furnace Access

[m2bandit]

Looking at furnace info online I can't find anything on these small vent furnaces. I believe my sail switch failed last night.

I think I have to disassemble my couch and this wooden box the manual shows access would be against the exterior wall, it's also good for nothing just says contact a professional for any issue.


Box appears to be held down with one screw. I'll have to check it out after I move.
Anyone have a real manual for these things? Dometic Df series.

[Marcm157]

Mine is under my refrigerator and I have to remove the unit completely to even access diagnostic info. Additionally, the thermostat and power wires had no way of being disconnected so I had to cut and then splice them back together. Its one of the dumbest designs I have encountered so far in years of owning travel trailers.

[Jagiven]

Which camper do you have?

Are you sure this is the furnace? Only reason I ask, I do not see a cold air return, gas piping, or HVAC ducts. Do you have ducts in your floor?

If it is the furnace, I feel you are really lucky. As Marcn157 stated, most of use have ours under the Frig, and you have to remove the entire unit to gain access. Lot of work.

I have removed a LOT of thin paneling within my HTT, fairly easy to do, but you have to take your time. Get a small crowbar (tiny little thing) slowly work your way around. Never try to get a staple out on the first try, or you will shatter the paneling. Work your way back and forth, prying up the staples just a little bit and move one, and come back and work it up some more. If you go to fast you will shatter the thin paneling.

Once the repair is done, I would use a couple screws to secure the panel, so you have easy access the next time.

Edit: I see a single screw in the frame holding the box to the floor (lower right side). I bet you might have a few more screws just like that one, and the whole box might just lift up and out of there.

[m2bandit]

Got it done, had to unbolt the couch bottom, unscrew the box, furnace and rotate the unit to get to the sensors and board.



Wasn't the sail switch but the ducting was pushing up against the furnace. No surprise it's a jayco issue on this lemon. There was also trash underneath the furnace box, cut wires stripped wire insulation.

Here's the my thread with the rest of their shoddy work. Doesn't include the bed being mounted 1.5 inches higher on one side yet.

https://www.jaycoowners.com/forums/f...ous-76820.html

[Rustic Eagle]

Originally Posted by m2bandit

Got it done, had to unbolt the couch bottom, unscrew the box, furnace and rotate the unit to get to the sensors and board.......snip

Just curious, did you take any photos of the furnace once the box was removed, and/or of the compromised ducting? What model 'DF' furnace did you find?

Dometic-Atwood web site has a pretty good Product Data Base & Manual Archive that I've used in the past.

Dometic-Atwood Documentation: https://www.dometic.com/en/se/support

I have a similar furnace set-up under my jackknife sofa and had operation issues as well.

Reference Posts #220 - #223 here: https://www.jaycoowners.com/forums/f...-51005-12.html

Bob

[m2bandit]

Originally Posted by Rustic Eagle

Just curious, did you take any photos of the furnace once the box was removed, and/or of the compromised ducting? What model 'DF' furnace did you find?

Dometic-Atwood web site has a pretty good Product Data Base & Manual Archive that I've used in the past.

Dometic-Atwood Documentation: https://www.dometic.com/en/se/support

I have a similar furnace set-up under my jackknife sofa and had operation issues as well.

Reference Posts #220 - #223 here: https://www.jaycoowners.com/forums/f...-51005-12.html

Bob

Thanks for the link, I'll add the documentation to my collection.
Mine is Model dfmd20121
I got a picture of the furnace itself but not the duct. The duct was pushed up in the middle so only the sides allowed air which must have lowered the flow too low for the sail switch.
It had about 6 square inch of opening al together instead of the 3 x 12" it should have had.

Runs fine now. I pulled the sail and there was no debris.

[m2bandit]

This is the sail switch location if you need to check that.

Upside down. Lol

[Rustic Eagle]

Appreciate the follow-up.

Yeah, I got to know my furnace fairly well during the 2019/2020 winter, and we share the same Dometic-Atwood #AFMD 20121 furnace placed under a box. I replaced my sail switch along with addressing a poor (almost non-existent) cold air return to the furnace blower motor louvers.

My main plenum under the furnace was fine, but did have two minor spots in the long run duct feeding the outlet vents that needed some attention.

Bob

[Jagiven]

Glad you got if fixed.

Did you modify the box so you can quickly access it in the future? Also a lot of people will move the black reset button to a location that is quickly accessible.

[Dick Patton]

My furnace failed and I had to remove the under counter grill detach duct and exhaust and rotate the furnace just to get to the the switches. Checked sail switch, ok and replaced flame sensor. Furnace still starts and burner ignites for 5-6 seconds and then shuts off. Any Ideas?