It's in the fifties here and I am trying work in the coach. Problem is the furnaces won't keep running. They only run for a 3-5 minutes and then shut down on high limit due to lack of air flow and blowing 190* air.. So it's still cold inside, my best guess based on 35 years of HVAC experience is they kept adding heat capacity to the units based on complaints without increasing duct sizes. Best practice would be get get half sizes furnaces and boost efficiency 30-40%
They used to short cycle all the time. Too hot. Then too cold. Repeat.
Design requires starting the fan at the same time as the blower in case of a internal leak.
When the furnace reaches the cutoff temp the flame goes off but the fan continues until the furnace box cools off a bit.
Plus the bedroom furnace points across the narrow hallway if memory serves me.
Part of the natural beauty of the vehicle
Unless the blower motors are bad? I can't imagine things wearing out after just 28 years.
Your furnace action sounds about "normal" to me. I have never timed our furnaces, but when they run they usually don't stay on long. They will keep the coach warm on average, but you have to accept fairly wide swings in room temperature. If we are plugged in to shore power, we prefer to use several small electric space heaters scattered around the coach, and keep the OEM propane heaters in reserve for emergency heat in case of power failure. The small heaters will do a much better job of maintaining a consistant temp throughout the coach, plus they are quieter, and probably (?) cheaper to operate.
Plus add a small fan up near the ceiling to circulate the air--prevents stratification of the hot air staying up "top" of the cooler air.
Recommend using the furnaces when it gets so cold the water lines might freeze. The furnaces in newer coaches heat the areas/compartments where it is crucial water doesn't freeze and damage things.
something else going on - I had two furnaces (noisy as hell) in my 1989 OREG, both worked fine - had coach in WI in below freezing weather many times, snug as a bug (of course the single pane windows were not my favorite in the cold with furnaces going)
Tim Fiedler
Sure Start Soft Start (http://www.gen-pro.biz)
TCER Direct (http://www.tcerdirect.com) generator-gas-prod (http://www.generatorgasproducts.com) 630 240-9139
Gen-Pro
It's that crappy American-made stuff, just don't last a lifetime any more! My files show our front Atwood furnace was replaced in 07. The rear Atwood I replaced this year, after being "re-built" by a PO. Typical of furnaces to cycle, that's their job, but, something is haywire with a furnace that won't let you just wear a tee-shirt inside! ^.^d I don't think it would matter, but has the electronic board been replaced?
You are probably correct that furnace is shutting down on high plenum temp. We found 'dummy' covers for extra distribution hoses. Removed the closed off covers and added additional outlets which eliminated the high heat shutoff. We just need to move more air. Be sure cold air return is open and all heat duct tubes are clear.
I got my furnaces checked today.. The circuit board on the front needed to be replaced. Both on them spit a cloud of crap when given a blast of compressed air.
Picking the repair techs for knowledge... a good blowing out is usually all they need. If there is anything providing resistance to air flow the flame won't stay lit.
batteries low, lowering fan speed causing overheat?
Tim Fiedler
Sure Start Soft Start (http://www.gen-pro.biz)
TCER Direct (http://www.tcerdirect.com) generator-gas-prod (http://www.generatorgasproducts.com) 630 240-9139
Gen-Pro