Furnace

[PowellsMonty]

I replaced the thermostat because I thought it wasn't working properly and I think something is still wrong. I have the thermo set at 72, furnace on & it turns off before reaching temperature. Thermometer says it is 68 in here. Why won't it keep running to higher temperature?
Thanks in advance!

[CORattler]

Place a thermostat right next to it at the same height.
If it read the same your therrmostat is OK. A operational thermostat wil satisfy the setting.
Maybe you are checking the temp in 2 different places, heights?

[jwedell]

First use a known good thermometer and varify that the thermostat reading is accurate. Second turn up the thermastat to 74 and see if it heats up to 70. I don't think the problem is in the furnace, probably still the thermostat. Good luck.

[PowellsMonty]

I replaced it with a Dometic again. Ours is a 2003 3295RK, What kind of thermostat shoul I replace it with? That is for simple old folks?

[DQDick]

Several issues could be in play including that the thermostat may be off a degree or two. Not really a problem you just have to set the thermostat to get the temperature you want in the room. As long as it's consistent it's not really a problem, you just need to know where to set it to get the comfort you want. Other issues could be an open space behind the thermostat causing it to read incorrectly. If the sun is on the side of the rig the thermostat is on and there isn't insulation behind the thermostat it could be picking up a couple of degrees from the sun on that wall.

[racerjoe]

Some duotherms have a reset feature. It might need to be reset. I think the heat function on those use 68 as a set point in case of problems. worth a try

[PowellsMonty]

if i put it on 80, it shuts off at 68. Will try to figure out how to rest. Thanks everyone.

[racerjoe]

try this:
1. Turn slide switch to OFF position
2. Press and hold MODE (top) and ZONE (bottom) buttons
3. Turn slide switch to ON position
4. Release MODE and ZONE buttons
5. FF appears indicating reset is complete

[PowellsMonty]

It fixed itself. Hate that sometimes, but it is working now. Thanks for all the help!!!

[thekennys]

mine is above the fireplace so i have to set it high to get the rest of the rig warmed up
mikey

[RJI47]

Mine does that to, although not as drastic. The problem on a 3400 is that the 32" television is right next to the thermostat, and that generates quite a bit of heat. If you have a separate thermometer on the counter, that and the furnace/a/c thermostat never agree. It gets pretty warm where the t-stat is.