Thermostat problem?

[juddspaintballs]

I'm pretty new to RV's. In December we listed our house for sale with no real plans of where to move, just a future idea of building on my parents' farm about 20 miles away. To our surprise, we had several offers the very same day we listed and signed a contract for more than listing a couple days later. With closing set only a month out, we had to scramble.




We had talked about buying a 5th wheel and living in that until we starting building a house a few months out. Well, here we are in our new-to-us Montana Mountaineer 350QBQ. We have four kids, so this layout is perfect for us. In just a couple of weeks, we had a gravel pad setup with a temporary power pole, a septic connection, and a hose bib. As part of the purchase, the sellers towed it and parked it in place for us since I don't have anything big enough to move it. We're only about 100' behind the farm house and have a second washer and dryer in the house plus another fridge and deep freezer.





All things being new, I've had a few issues but nothing I can't figure out until now. The furnace runs oddly and I think it is a thermostat issue.


The first couple of weeks, the furnace would run for a few minutes then turn off for a few minutes, then turn on, etc. I thought this to be normal, especially since the furnace was actually firing and producing heat. No issues as far as I know. Now, it seems as though the furnace either runs too much or not enough.



I have the set temperature at 67 since last night and the Dometic CCC2 thermostat says it is 74 degrees inside temperature. I haven't heard the furnace kick on in hours and it is only 30 degrees out. The other night, the thermostat was set at 67 and it said it was only 63 inside, but I was burning up when I went to bed and still burning up when I got up for work. The furnace ran almost non-stop I think in that timeframe.


Since I'm pretty new to RVs, my first instinct is that this is a thermostat sensing issue. Some Googling suggests I could be right, or way wrong, depending on who you listen to. As far as I know, there's a temperature sensor on the wall in the bunkhouse area and none in the main living area or the front bedroom. It appears the main control board for the thermostat is installed in the rear AC and there's just wiring inside the front AC cover. Does this mean Zone 1 is the rear bunkhouse AC or the front bedroom AC (and which one cools the main living area?) If there's no temperature sensor in the main living area or the front bedroom, is the thermostat the temperature sensor then?




How do I fix this problem? I've turned the thermostat off and held the "Mode" and "Zone" buttons until it read IniT and then turned it back on with no change in performance. I even tossed the thermostat in the freezer for 10 minutes and then plugged it back in. It was reading an inside temperature of 71 degrees at that point. We aren't freezing with the fireplace heater and a single electric space heater going, but it would be nice if the furnace worked properly.

[juddspaintballs]

An interesting thought:


I was curious if Zone 1 was considered the bunkhouse or not. It seems as though, it is. Since the inside temperature for the furnace ONLY reads Zone 1 and the temperature swing in the bunkhouse can vary greatly if the door is open or closed, that could be the problem. I had a space heater in that room with the door closed, so the temperature could easily have been as read on the thermostat while the main living area and front bedroom was far colder. This would also explain why we were roasting the other night since the kids were staying with the grandparents so we had the space heater off in that room and the door closed. The furnace doesn't blow much out of that bunkhouse vent in comparison to the bedroom and main living vents.

I tested this theory out by putting a bag of frozen food over the temperature sensor in the bunk house for a couple minutes. The temperature dropped down to 66 in just a couple minutes and the furnace kicked right on until it was satisfied.


So, problem solved?

[RMcNeal]

I'm no expert but I thought I would chime in. It sounds like you are on the right track. Many of these systems have a remote temp sensor and it sounds like yours is in the bunkhouse. In my experience, Zone 1 is the main living area (rear) and Zone 2 is the bedroom (front), but that may be reversed in front living units. I haven't had any experience with those.
Our unit does not have a bunkhouse or remote sensor, but the thermostat is above the coffee bar in the kitchen. The upper levels, front and rear, can easily be 10 degrees warmer than the kitchen lower area. Hot air rises, as they say. And I have noticed that the thermostat is greatly effected in the morning when I make coffee on the coffee bar and the heat from the coffee maker is inches from the thermostat. Seems like poor placement for the thermostat, but in all honesty, I can't find another place that it might be better, so I've just learned to work around the problem.