Furnace thermostat error df


The furnace thermostat error df was the message that I started seeing on the getlowercooling.com website I purchased years ago when the system had been keeping heat all winter long. “The furnace has continuously been running.”

This confusion could have easily been avoided if I had received emails notifying me of anything that was going wrong.

My home is insulated, and it’s only a 1,000-square-foot ranch-style house in Colorado. It shouldn’t be this hot in here! Instead, it’s more like eighty-five degrees and humid from my air conditioner running constantly to compensate for the insulation on the walls.

I disconnected my thermostat to figure out what the problem was: The display showed an error message indicator code df on one digit in red letters.< br> Wiring checks found no problems with my furnace or electrical outlets, so I

If the furnace’s pilot lights won’t stay lit or you smell gas, stop using the furnace and leave the home immediately. The following are possible problems:

Electrical Service: Make sure to keep the distance between wires at least 18 inches apart, and make sure all screw terminals and binding posts are tight. If you replace any wires, including switch wires, you should label each one before plugging it in. This will keep accidents from happening.

Gas furnace thermostat new installing the purging the pilot light switch step

Excessive short cycling can lead to system overheating and may cause damage to other heating components

This post is about “df”, which stands for “dual fuel”

This post is about the furnace thermostat error df. In this post, I will be discussing what this means, what you should do in the event this error happens to your thermostat, and the best way to prevent it from happening.

Then I will discuss how to solve the df error when it does happen from our technician’s perspective. Once we have discussed both sides of the argument in detail, we will review whether or not this problem seems difficult to fix or not depending on who you are (the consumer or our techs). Our final verdict on DF errors and possible resolutions is shown at the end of this article. You can take it all with a grain of salt after you read both sides of the argument- especially if you don’t like flipping through long sections filled with text.


This post’s introduction talks about a type of furnace thermostat error called DF

We can troubleshoot furnace thermostat error df problems by checking and analyzing each checkpoint.

The power relay is the first line of defense.  It works to protect dormant systems in the event of a power outage and or loss of power to your HVAC system.  If you are experiencing a furnace thermostat error df, one possibility may be that it does not recognize that sufficient power is present at startup. Another possible option for this issue is a technical fault in the fuse link

Energy waste and expensive heating bills are becoming common with old thermostats, like analog thermostats. However with a modern thermostat that is easy to install, like a Nest thermostat, and more affordably, customers can save on heating bills by up to 15%.

Maintaining your furnace is not as difficult as you think – one way is to simply switch your furnace’s settings so that it only heats when necessary from 7 am-6 pm. All our furnaces will switch back off automatically at 7 pm, so it takes less than a minute.