What kind of heating system do you have? Does the thermostat also control air conditioning?

How old is the thermostat (roughly)?

It certainly sounds as if the thermostat is failing.

Replacing a thermostat isn't tough, but it can be tricky depending on how many functions it controls and what kind of power feed it has. Most thermostats use low voltage, but some systems, normally older ones or electric furnace models, can use line voltage (110 volts).

kframe,
Thank you for your help, I wish I could tell you more...The brand is Totaline, though the house is 50 years old it is not the original thermostat as you can see it at some point replaced an old round one. It does control our air conditioner as well. I think that our heating is electric...I'm pretty sure.

The whole thing has happened very suddenly, we never had a problem and then very quickly we had this overwhelming smell. The strange thing is that even though the thermostat stayed on through the night the smell did go mostly away until I noticed it again this morning. I have it off right now and in the 15 below temps we have now I'm concerned about the pipes if I keep it off...what do I do?

Here's a picture if this helps...
{{gwi:1541414}}From Kitchen!

Unfortunately I can't see your picture because of restrictions at the office.

Many older thermostats had a little electric heater in them that was called an anticipator. It was to help keep the heat even by helping control the thermostat.

My guess is that the anticipator on your thermostat is going bad and overheating.

Your best bet at this point, given the weather conditions you're facing, is to call your service company and have them come in and replace it.

Turn your heat off at the breaker, and call a heating and air conditioning company immediately.

If they can't come out right away, arrange to get some portable heaters form friends or where and plug enough in to keep the house above freezing. Open cabinet doors under sinks and other places with faucets or water pipes. Leave the doors open. Open the facets and run water very slowly to prevent the pipes from freezing.

Darn, wish we could edit these posts. That should read portable heaters from friends or wherever, and plug enough in to keep the house above freezing.

Is there a model number on that thermostat anywhere? Totaline has a website with instruction manuals for its thermostats. You should be able to get the manual for your thermostat to see if it's line voltage, low voltage, or what.

After that it simply becomes a case of purchasing a thermostat, say a Honeywell or Hunter, from Lowes, Home Depot, or similar, and carefully following the instructions to install the new one.

From the photo it certainly does not look like a line voltage thermostat, but it doesn't matter, it needs to be taken care of by a professional.

There is the possibility that it isn't the thermostat itself, especially since the system still seems to be working. The odor may be coming from inside the wall. Thermostats have a wiring penetration hole behind them, frequently left unsealed. It is not uncommon for air currents to exit this hole. That may be the source of the odor. It should be taken care of immediately.

I vote get rid of it. Electronics only have so much magic smoke and that is what you smell. If all that magic smoke goes out it will quit working. Kind of like a light bulb will only suck so much dark and when its full it stops working until you replace it. Hold the new one up with the old one and compare how much dark the old one sucked, pretty impressive. Electronics are much more mysterious and only give that telltale odor.

enigma

always err on the side of safety as well as piece of mind. thermostats do fail. replace the stat.

IMO