How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the leading thermostat producers, and we proudly install them on a regular basis in Fort Myers. They’re durable and trustworthy. In addition, Honeywell is constantly improving its technology, offering more features for your family.

However, each thermostat can experience problems now and then. That’s why we’ve put together this valuable manual to go over troubleshooting. While Honeywell thermostat problems are rare, they do occur. 

While you can typically fix the majority of thermostat issues alone, they often require Expert support. Our home comfort professionals are available to assist you when you need us. We’re only a call away at 239-908-6991.

Let’s begin the process by finding out what model of thermostat your house has.

What Model of Thermostat Do I Have?

There are three kinds of thermostats:

  • Manual—This is the older dial-shaped thermostat. You won’t run into error codes with this type, but it’s also the least efficient for lowering utility bills.
  • Programmable—This thermostat features a digital screen and arrows you use to choose your desired temperature. You can also set daily programs to lower the temperature when you’re at work and increase it when you return.
  • Smart—You won’t have to make any programs on this thermostat, since it picks up on your schedule. It instinctively adjusts the temperature when you or loved ones are gone to help you save on heating and cooling bills. You can also change the temperature anywhere on your phone or other Wi-Fi-enabled device. 

As is the case with most technologically advanced solutions, there are several problems that might happen. The majority of of these problems don’t require pro support and are uncomplicated enough to repair by yourself.

Common Honeywell Thermostat Problems

All thermostats have a unique kind of codes matching the troubles that take place.

Think how uncomplicated it can be to fix a computer by restarting it. For the most part, correcting a thermostat can be just as uncomplicated.

Here is a listing the most common Honeywell thermostat issues. These apply to the following programmable thermostats:

Display is Blank

If the screen is empty on your programmable thermostat, you could need to install new batteries. If that doesn’t take care of the problem or you use a smart thermostat, there may be a wiring problem.

Next, you should check the power is enabled for your furnace or air handler. Make sure the switch by the indoor system is in the “on” position.

Also, you should confirm all furnace cabinet or air handler doors/panels are securely fastened.

A loose panel may trigger the safety switch, which disconnects power to the unit.

Less frequently, a clear screen might signify you need to get a new thermostat.

Heating and Cooling Equipment Won’t Start

Ensure that your thermostat is set to “cool” or “heat,” not “off.”

In the summer, make sure you set the thermostat lower than the ambient temperature. In the winter, confirm it’s higher. This sounds absurd, but we’ve seen it occur lots of times.

Confirm the power switch near your indoor equipment is in the “on” position. You should also check the cabinet doors or panels are closed on your furnace cabinet or air handler. An unsecured panel can trigger the safety switch, stopping current to the equipment.

System still won’t turn on? Confirm circuit breakers haven’t turned off and that your HVAC system isn’t displaying error codes.

“Cool On” or “Heat On” is Blinking

To start, ensure your thermostat is set to “cool” or “heat.”

Then, check it’s signaling the correct system to start. This is typically indicated by “cool on,” “heat on” or an icon.

If these words or the picture is blinking, your thermostat is in a five-minute delay mode. This mode protects your unit from damaging short cycling. This may occur if you lose electricity.

Honeywell Thermostat-Specific Error Codes

Honeywell Lyric™ T5 Wi-Fi (RCHT8612WF/RCHT9510WFW)

  • 164—Heat pump requires service. Call Service Experts Heating & Air Conditioning at 239-908-6991 for support.
  • 168—Wi-Fi radio error. Contact Lyric technical support at 800-633-3991. 170—Internal memory error. Contact Lyric technical support at 800-633-3991.
  • 171—Set date and time. Finish these settings so scheduling can take place.
  • 173—Thermostat temperature sensor error. Contact Lyric technical support at 800-633-3991.
  • 175—AC power restored. No action necessary.
  • 181/182—Put in a new air filter. Clear the display by hitting “dismiss” after putting in a new filter.
  • 184—Put in a new humidifier pad. Clear the thermostat by touching “dismiss” after putting in a clean pad filter.
  • 185—Put in a new dehumidifier filter. Clear the display by hitting “dismiss” after adding a fresh filter.
  • 187—Rinse or install a new ventilator filter. Clear the thermostat by touching “dismiss” after installing a clean filter.
  • 188/189—Replace UV bulb. Call Service Experts Heating & Air Conditioning at 239-908-6991 for assistance.
  • 210—Register online for outside temperature. Download the Lyric app to do this step and ensure accurate thermostat operation.
  • 388—Register online for remote access and exterior temperature. Download the Lyric app to finish this step and ensure proper thermostat operation.
  • 399—No Internet. Verify your network settings.
  • 400—No Wi-Fi signal. Wait for the thermostat to reconnect or select new Wi-Fi network.
  • 508—Wi-Fi not set up. Use the Lyric app and follow the steps to link your thermostat.

For more details, view this thermostat’s user manual.

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump must be serviced service. Contact Service Experts Heating & Air Conditioning at 239-908-6991 for assistance.
  • 168—Wi-Fi radio error. Contact Service Experts Heating & Air Conditioning at 239-908-6991 for assistance.
  • 170—Internal memory error. Reach Service Experts Heating & Air Conditioning at 239-908-6991 for support.
  • 171—Set date and time. Complete these settings so scheduling can operate.
  • 173—Thermostat temperature sensor error. Call Service Experts Heating & Air Conditioning at 239-908-6991 for help.
  • 175—AC power restored. No action necessary.
  • 177—Indoor temperature sensor error. Call Service Experts Heating & Air Conditioning at 239-908-6991 for support.
  • 178—Outdoor temperature sensor error. Reach Service Experts Heating & Air Conditioning at 239-908-6991 for support.
  • 181/182—Get a new air filter. Clear the screen by tapping “dismiss” after adding a fresh filter.
  • 183—Clean humidifier tank and install a new water filter. Clear the monitor by hitting “dismiss” after doing these procedures.
  • 184—Get a new humidifier pad. Clear the monitor by hitting “dismiss” after adding a new pad filter.
  • 185—Install a new dehumidifier filter. Clear the display by tapping “dismiss” after adding a fresh filter.
  • 186—Rinse ventilator core. Clear the thermostat by hitting “dismiss” after completing this task.
  • 187—Rinse or get a new ventilator filter. Clear the display by touching “dismiss” after installing a new filter.
  • 188/189—Get a new UV bulb. Get in touch with Service Experts Heating & Air Conditioning at 239-908-6991 for support.
  • 210—Register online for outside temperature. Use the Lyric app to complete this step and ensure correct thermostat operation.
  • 388—Register online for remote access and exterior temperature. Download the Lyric app to finish this step and ensure accurate thermostat operation.
  • 399—No Internet. Check your network settings.
  • 400—No Wi-Fi signal. Wait for the thermostat to reconnect or select new Wi-Fi network.
  • 508—Wi-Fi not set up. Use the Lyric app and follow the procedures to connect your thermostat.

For more specifics, look at this thermostat’s user manual.

Our Experts are Ready to Help

If you’re still having problems after trying the troubleshooting steps, our Experts are here to help. Call us at 239-908-6991 and we’ll arrive as fast as we can to determine the malfunction.

If you have an older thermostat, right now is a good time to think about a new thermostat. Thermostat technology has advanced over the last few years. Ask us for more details on how smart thermostats can make your house better while helping save on heating and cooling expenses throughout the year.

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