Duo-Therm 901 series

[jagcb750]

I was wondering what the easiest way to pull out the front furnace (under the sink) from a 1986 345 is. I just tried to fire it off and it just blows cold air. I hear it click three times I assume that it is trying to ignite. After three times it doesn't try anymore. Just blows cold air. Oh, the one located in the rear of the coach works fine, as does the cook stove and water heater. I've been reading a lot of posts in these forums on furnaces. Seems there are several switches and control boards involved. (Sail switch, Limit switch etc.) I wonder if anyone has pictures available where these components are located.

[jagcb750]

Well, believe it or not, after reading some posts I decided to try something. I read that you could sometimes bang the unit a bit and get it to light off. I figured what did I have to lose, right? So I turned the thermostat up and I heard the click sound and nothing. Then I slapped the unit on the left side a coulple of licks. then I heard it rumble and start up. Amazing. Who would have thought that if something doesn't work. Smack it around a little and it would work for you like an old Burrow? Hee Hee. Anyway, It shut off after a minute or two and I cranked up the thermostat a little more and it fired back up again. I let it run for 5 minutes or so and then I cut it off. Sounds like my sail switch was stuck or something. Any ideas on this?

[Robfike]

I had to just replace my rear unit due to bad blower bearings. The blower would turn but just not fast enough to make the sail switch move.
After I removed the unit I discovered the exhaust tube had rusted badly where the outer and inner tubes slide together. I'm very glad it's gone.
Both of my original Duo-Therms have now been replaced.
Rob

[jagcb750]

Wow, I was trying to avoid having to replace mine. Do you feel like the replacements are better? More efficient?

[Robfike]

I don't know if it's any better, but it's new not 21 years old. I had no idea that the exhaust tube was so rusted on my old unit until I went to pull it out.
We could have had a real carbon monoxide problem not to far in the future.
Rob