accessing the Sail Switch and Circuit board

[Robertk]

Can anyone point me to documentation on how to access them on a Cougar 34 TSB. I can't for the life of me figure out where they are.

[sourdough]

The sail switch will be inside the furnace. Do you know where the furnace is? Is it Atwood or Suburban (Atwood generally has one vent hole outside and Suburban 2). Mine is Atwood and my control board is accessed from outside the trailer.

[Robertk]

My furnace is a DFMD45 Dometic it has one vent hole outside which must mean the circuit board is inside the furnace. I'm just I can see how to take the cover off. However it looks my 10 year old would have trouble getting his hands inside.

[sourdough]

I am assuming you probably have a 35k unit in the trailer. Here is a link to a 35k Atwood furnace;

https://www.amazon.com/Atwood-Hydro-32690-Furnace-Medium/dp/B016V280GG/ref=pd_di_sccai_2/145-0434691-9040727?_encoding=UTF8&pd_rd_i=B016V280GG&pd_rd_r=0c3c2f7a-d758-4ef1-b67a-9bec37d5e151&pd_rd_w=ut7vc&pd_rd_wg=OUBba&pf_rd_p=7d91b49a-6b22-4dfd-8a2a-1555d90a4698&pf_rd_r=ECRK55P3FP87V8BCVF6S&psc=1&refRID=ECRK55P3FP87V8BCVF6S

Does your exterior cover look like that? If so, remove the 4 screws then work on the exhaust port to wiggle it out and the entire cover, exhaust port and all will come off. The control board is inside by the squirrel cage if I recall. Pulling that exhaust port out can be rather difficult but it is just "pushed" up into the exhaust tube coming out of the furnace.
Edit: I don't remove the 4 screws for the exhaust port. I leave it on and use the panel (very gently or it will bend) to help leverage on the port.

[jhplak325]

You will need to pull the furnace in order to access the sail switch and circuit board since the Cougar 34TSB does not have the exterior door.

[sourdough]

You will need to pull the furnace in order to access the sail switch and circuit board since the Cougar 34TSB does not have the exterior door.


It appears you are correct. I've looked at a couple of videos and all they have is the exhaust port coming out the side. Inside access and removal appear to be mandatory for any maintenance/repair which would be close to a show stopper for me.

[Northofu1]

MAKE SURE YOUR PROPANE TANKS ARE OFF AND BLEED LINE FROM STOVE TOP BURNER.
I found a wrench and adjustable pliers work well to remove gas line. The line is malleable so moving it out of the way is fairly easy.
The air supply hoses are removed with a 1/4 turn off, no need to mess with clamps. you can mark them if you think you need to. there will be a couple of screws holding the furnace to a wooden base, remove them and pull unit into coach onto a blanket or something to protect floor.
You basically have to remove fan assembly, surprisingly simple. once its removed the sail switch is inside the fan cage, mine had a few screws that needed to be removed and it splits in half.

In the link is the sail switch you need, two screws two wires. Always take pictures as you remove wires etc. so you know where they all go when reassembling. I was nervous at first but it's not that bad. Did I mention taking pictures? LOL
https://www.amazon.com/Atwood-36680-Sail-Switch/dp/B004QMX9WY/ref=sr_1_5?dchild=1&keywords=atwood+3500+sail+switch&qid=1592264895&sr=8-5
When I changed mine last year I added male / female spade connectors to the thermostat leads for future maintenance.
Once re-installed, attach gas line and make sure the YELLOW teflon tape for gas appliances is used. Soapy water in a squirt bottle to test for a solid connection works well. Make sure there are no leaks and test it a few times once the furnace is operating.
This of course is assuming you have the tools and are somewhat handy.
If you feel this is above your skill set, get a "professional" to do the work.

[Sjbekwils]

Can anyone point me to documentation on how to access them on a Cougar 34 TSB. I can't for the life of me figure out where they are.

What was your original problem?

I have a 2018 Loredo 325RL that the furnace fan runs continuously and I will need to get into the control board too.