Furnace thermostat question.

[KATMAN]

My furnace has been acting up,now that cold weather is setting in. Last week,the furnace wouldn't come on,as the tempature dipped into the teens.Now it comes on but it won't go off.We bought a new thermostat,but haven't put it in yet.It needs one anyway,but do you think that is the problem,or do I have to get a repairman over here to check it out? They were here when It wouldn't come on at all,but it's been messing up ever since. What do you think the problem could be?

[Reynolds357]

My furnace has been acting up,now that cold weather is setting in. Last week,the furnace wouldn't come on,as the tempature dipped into the teens.Now it comes on but it won't go off.We bought a new thermostat,but haven't put it in yet.It needs one anyway,but do you think that is the problem,or do I have to get a repairman over here to check it out? They were here when It wouldn't come on at all,but it's been messing up ever since. What do you think the problem could be?

Sounds like it could be the thermostat. Will not come on could be many things, but will not turn off sounds like the thermostat.

[JohnDB]

If you are using gas heat...

Yeah...

There are so many different things that it could be that will keep it from starting it isn't funny.

Sounds like hekel and jeckel fixed it good when they were out last and bypassed most every safety device on there to get it to work.

Call them back out and tell them they screwed it up and to fix it right.

Usually it means a new circuit board. (on their dime this time)

Thermostats are funny criters. They are usually just bridge circuits (diodes) and a temperature sensor. So....they either work or they don't.

You can install the new thermostat but I seriously doubt it is going to fix anything. (and I would before you call them jokers back out)

This is electronics and the color scheme for electronics is different than electrics. I think of white as neutral but in electronics white is signal and black is neutral. (really strange IMHO) Green can be anything in Electronics. But in electrics it is ground.