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Heating, Air Conditioning, Fridge, HVAC/Thermostat auto mode on gas furnace



A couple of months ago, I purchased my first home and have recently been experiencing an anomaly with the thermostat and gas furnace.

The thermostat is always in a manual temperature mode (it is not programmed).  On Friday, 3/7, and Friday 3/21, I woke up in the morning to find the indoor temperature in the 50s, even though the temperature is set to 65.

If I slide the thermostat to the off position and back on, the furnace turns on immediately and reaches the set temperature.

It seems strange that is has only happened twice, and the rest of the time it works without any issue.  Any ideas on what may be the cause of this issue would be appreciated.


ANSWER: Hello John, I have seen this many times and it is usually a problem in the furnace. But your problem is a little different. It sounds like it might be in the stat. Check to see if the stat has batteries, some do and some don't. If it has batteries replace them.

I hope this helps. If you have any other questions let me know.

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QUESTION: Thanks for the response.  The thermostat does have batteries, and I replaced them after an extended power outage drained the old batteries in an ice storm back in early February.

I can try swapping them out for new batteries again, unless you think there is something else to check.  Thanks.

John, if you replaced batteries in February I think your ok. When the furnace failed did have you to turn the breaker off and on at the furnace? Or just at the stat?

I would turn the breaker off to the furnace and pull the covers off the furnace. Find the stat terminal in the furnace. They should be labeled R,G,W,Y........ Make sure  the wire's are secure. Do the same at the stat.

If it fails again take the stat off to expose the wire's. Jumper R to W then wait a few minutes and see if the furnace starts. If it starts the stat is bad.

Let me know.

Heating, Air Conditioning, Fridge, HVAC

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Jim S.


I can answer questions on gas or electric furnaces, ac units and heat pumps. I don't work on boilers,chillers,or home appliances.


I have been in the HVAC trade for over 35 years. For the past 15 years I have owned my own business. I am semi-retired so I can answer questions in a timely manner.

I attended trade school for 5 years on weekends and evenings. This was very hard to do, but well worth it!

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