Furnace Keeps Running and Running

Updated on January 14, 2011
B.W. asks from Bethel Park, PA
7 answers

My gas furnace has just started to keep running and running even after it is way warmer in the house than the thermostat is set for. Has anybody had this happen to them before? What could the cause be? I have completely unhooked the thermostat twice and it still keeps doing it. I am hoping to avoid calling an HVAC repairman out.

It is on auto, not run. If the thermostat is disconnected, the furnace will turn on.

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So What Happened?

i prayed last night and it worked all night and all day today.....if it happens again, i'll probably try to replace the thermostat.

More Answers


answers from Cincinnati on

I agree with the other moms. Replacing the thermostat will cost like $40 at Walmart. They're easy to switch out. If that doesn't take care of it, then you may have to call in the HVAC repairman. Good luck B.!



answers from Pittsburgh on

This happened to me when I was living in my old apt. There is a switch on the furnace itself. Try turning it off there, leaving it off for 5-10 minutes and turning it back on. That resolved my issue.


answers from Philadelphia on

Have you tried replacing the thermostat? They cost between $20 to $50ish
and are very easy to install.


answers from Cleveland on

like the other post said it could be a sensor i would have someone come out and take a look at it. it will be cheaper then paying a 600 gas bill



answers from Johnstown on

I asked my hubby because he knows some about these things. He thinks it is the thermocouple. That usually costs about $40-$50.



answers from Detroit on

You might need a new thermostat. Or it could be a little sensor in the furnace itself that was the problem my daughter and her husband had. I would check the thermostat first.


answers from Sacramento on

Have you had your ducts cleaned recently? Some systems have sensors in the return air ducts. Dirt can cause them to read incorrectly. Take off the return air grilles and see if you can see any sensors in there - and if so, vacuum the area.

Honestly, it's not a bad idea to have a repair guy out there. When you're dealing with a gas appliance that's on the fritz, why not have a professional perform a maintenance service on it and troubleshoot the issue? If they give you a crazy estimate to repair it, you can get a second opinion. In my experience (as a construction manager) ignoring these types of issues can cause a lot of harm to expensive equipment. Taking care of it right away is almost always less expensive.

Good luck, I hope it's an easy fix!

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