How to Troubleshoot a Honeywell Thermostat Not Working?

Honeywell has an impressive line of thermostats, and while most have proved incredibly popular with consumers, problems can occur with even the best thermostats. If you’ve been looking for Honeywell thermostat help, you’ve come to the right place, as our guide will help you troubleshoot common issues with their systems.

Troubleshooting Honeywell Thermostats

Honeywell thermostats fall into three basic categories with programmable and non-programmable, along with connected thermostats. In this section, we will touch on problems with their traditional systems as smart thermostats can have their own particular set of issues. With that in mind, some of these problems can occur with those models as well.

Honeywell Thermostat Not Cooling

Nothing is more frustrating than finding out that your central system isn’t cooling down your home on a hot summer day. When this occurs, the first thing you want to do is make sure it’s set to the “cool” setting or the on position and that any panels are closed.

If the system is set on cool, make sure the temperature is set below the temperature in the room for the air conditioner to turn on. If all of the above factors check out and the thermostat still is not functioning, look for a flashing icon on the display. If you see one, that means the thermostat is currently in delay mode and should work normally within 5 minutes.

When all else fails and no circuit breakers are tripped, it may be low Freon or another problem with your air conditioning unit. In either case, you’ll want to call in an experienced technician to take a look at your system.

Honeywell Thermostat Won’t Turn on Heat in my Home

Not having air conditioning for a few hours in the summer can be uncomfortable, but there are other ways you can cool down homes naturally. Things are different with heat, so when your Honeywell thermostat won’t turn on heat in your home, it’s usually time to grab some blankets and call a technician.

Tripped circuit breakers are the most common reason why your heat may not function. You may need to ensure the furnace is on and the cover is closed in some cases. If you feel any air, even if it’s cold, you can rule out problems with the fan. You will also need to call a service technician if you can’t diagnose the issue using your owner’s manual.

When your Honeywell thermostat won’t turn off heat, it can be just as big of a problem as the heat not coming on at all. Unfortunately, this usually happens if your thermostat is broken, has bad wiring, or a faulty switch. The primary controller could also be damaged, or you could have a problem with a check valve if you’re using a radiator-based system.

Thermostat Display Problems

Next to the heat not turning on or off in your home when it should, the next most common problem with Honeywell thermostats is the display itself. You can experience several issues when using a thermostat with a digital display, although most come down to an issue with power.

With systems that use batteries, the Honeywell thermostat blank screen problem typically occurs when the batteries in your thermostat are low or bad. From flashing symbols to fading digits, a fresh set of batteries is a quick and inexpensive fix. If your system is hardwired, the problem can be a bit harder to diagnose, but there are a few steps you can take on your own.

Loose wiring, open furnace doors and tripped electrical breakers are two reasons for a blank screen on a Honeywell thermostat. If the breakers haven’t been tripped, you can refer to your user manual and remove the cover to inspect the wiring if that’s something you are comfortable with. If not, this is another instance where your system will need to be checked out by a certified professional.

Improper Installation

While you need a contractor or HVAC technician to install a new HVAC system, millions of homeowners rely on a handyman or relatives when it comes to thermostat issues. That’s because of the cost of service calls as nobody wants to pay a large fee only to have someone tell them their batteries in their thermostat are dead. If you installed the thermostat yourself or it’s been worked on since its initial installation, you’ll want to pay close attention to this section.

Thermostats are relatively simple devices to install, but a small mistake can significantly impact how your system performs. With older manual thermostats, the easiest way for homeowners to check for an improper installation is to locate a level. If the thermostat is not level, your problem can be solved with a few simple tools in about 5 minutes.

Older thermostats rely on mercury switches, which need to be level. If it’s a few degrees off, the temperature in your home will not be accurate. It can also cause your thermostat to not come on or even short cycle, which can lead to a variety of other issues down the line. If you have a level and screwdriver handy, you simply need to detach, level, and reattach the thermostat to the wall.

It’s also important to note the location where your thermostat is installed. Does it experience a lot of direct sunlight, or is it a neutral position in your home like a hallway? Even the most intelligent Honeywell thermostat will have trouble taking an accurate reading if it’s installed near an air vent, window, or warm areas like kitchens.

Troubleshooting Honeywell Smart Thermostats

All of the Honeywell thermostat problems we’ve covered so far will apply to their Resideo lineup and connected thermostats. As these are premium thermostats with more high-tech features, there are several other issues you’re likely to encounter as well.

With connected thermostats, we found that 90% of the issues and consumer complaints come from connectivity problems. If you can’t control your system remotely, you’ll want to make sure you have the right mobile app installed.

The company actually has several, and the Honeywell Home App is geared for their Round Smart Thermostats and the T-Series thermostats. If you have a VisionPRO, Prestige, or FocusPRO thermostat, you need to have the Honeywell Total Connect Comfort App installed. Both are available through Google Play and the App Store, and each has a specific troubleshooting section.

There are far too many reasons why a mobile app won’t connect, so your best bet is to refer to the app’s official support documentation in question. That said, things like router distance can impact connectivity along with the building materials used in older homes. You can also try resetting your modem, restarting your phone, or uninstalling and reinstalling the mobile application to fix connectivity problems.


We hope our guide to troubleshooting Honeywell thermostats was helpful, and it was able to get your HVAC back up and running again. If you were unable to find a solution or have an older model from the company, it might be time for an upgrade. Whether you’re looking for a new Z Wave thermostat or something a bit simpler, we have you covered.

Honeywell Thermostat FAQ

Q: Can I use rechargeable batteries in a Honeywell thermostat?

A: If you’ve ever encountered the Honeywell thermostat blank screen issue, it could be due to the batteries used in the system. The company recommends using standard batteries, not rechargeable ones

Q: How do I clean my Honeywell thermostat?

A: Even with a cover firmly in place, the inside of your thermostat will become dirty over time. To clean the inside, you need to remove the cover and clear any dirt or debris with canned air or a small paintbrush. If the wiring looks corroded or damaged, contact a specialist to have it serviced.

Q: What’s the best way to dispose of an old mercury-based thermostat?

A: Any thermostat with a mercury switch will need to be disposed of carefully. You can locate a wholesaler or waste transfer station that can properly recycle these units through the Thermostat Recycling Corporation.

Q: How to set Honeywell thermostat without an owner’s manual?

A: While manual or traditional thermostats simply require you to flip a switch and move a dial, newer models can be challenging to program. If you own a digital or smart thermostat from the company but no longer have the user manual, you can access one online by using the model number for your thermostat.  

Q: Will my thermostat work if the batteries are low?

A: Yes, although you may get a warning telling you it’s time for a new set of batteries. When they die, your system could stop working or lose partial functionality.

Q: How do I reset a Honeywell thermostat?

A: Any Honeywell thermostat that’s hardwired or relies on batteries can be reset. The process varies, however, so you’ll need to refer to your owner’s manual or the company’s official website to find the steps for your model. 

Written by

Rene has worked 10 years in the HVAC field and now is the Senior Comfort Specialist for PICKHVAC. He holds an HVAC associate degree and EPA & R-410A Certifications.

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