Replace Atwood thermostat

Honeywell TH1100DV1000 HEAT Digital T-stat....




Simple Install..remove old install new connect the 2 wires and install 2 AA batteries

Thanks everyone for your advice. I think the thermostat contacts have worn themselves out. It has not been used much the heater that is and if I play with the toggle switch it does come on or if I touch the contacts it will start up. Furnace does heat up but I have to start it by playing with the thermostat.

I replaced my thermostat with the same one as j-d but unfortunately they no longer make it and it is impossible to find, the newer model should work just fine. I control both A/C and heat with mine. I like it because you can set it to one degree or 2 degree of desired temp and the digital read out is a real plus.

I bought a Hunter Non Programmable that looks about like this at Walmart. The left panel is hinged for switches, and the right is hinged for 02 - AA Batteries. Mine isn't quite the same because the one I pictured has a "Filter Change Alert" and apparently 03 temperature modes.
On mine, the wall thermostat controlled Furnace ONLY and there were only 02 wires coming out of the wall and connected to the OEM thermostat. If you have a wall thermostat for your A/C, I can offer that I haven't tried to use one of these to control both, BUT others have, successfully, in several cases. I think somebody could post a link to such a project. If you're not controlling A/C as well as Furnace, just connect 02 wires and go.
We use the furnace only rarely, but I really like the conversion when we do.

Standard two wire thermostats can be replaced with most millivolt thermostat and many digital thermostats. Digitals are larger but work better when set up correctly.
Digital thermostats run off battery with in the thermostat and should be replaced every few months.
Millivolt thermostats are mechanical. There is an attenuator that acts like a resistor to change temperature differential. These give up the ghost faster then the thermostat contacts. My guess this is whaty is wrong wiith yours.