How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the best thermostat manufacturers, and we proudly install them on a regular basis in Ravenna. They’re durable and trustworthy. Plus, Honeywell is frequently updating its technology, resulting in more features for your family.

Still, all thermostats can run into errors occasionally. Due to this, we’ve compiled this helpful guide to walk you through troubleshooting. While Honeywell thermostat problems are rare, they do pop up. 

While you can often solve many thermostat troubles alone, they sometimes require Expert help. Our home comfort professionals are here to support you when you need us. We’re just a call away at 330-236-4793.

Let’s get started with the process by figuring out what model of thermostat your house has.

What Type of Thermostat Do I Have?

There are three types of thermostats:

  • Manual—This is the classic dial-shaped thermostat. You won’t run into error codes with this type, but it’s also the least efficient for reducing heating and cooling expenses.
  • Programmable—This thermostat features a digital screen and arrows you use to set your desired temperature. You can also choose daily programs to reduce the temperature when you’re away and increase it when you get back.
  • Smart—You won’t have to schedule any programs on this thermostat, because it picks up on your routine. It automatically raises and lowers the temperature when you or loved ones are out and about to help you save on utility costs. You can also change the temperature anywhere using your phone or other Wi-Fi-enabled device. 

As you’re aware most technologically advanced products, there are regular problems that can occur. Many of these situations don’t call for Expert support and are easy to repair by yourself.

Common Honeywell Thermostat Problems

All thermostats have a special set of codes that correspond to the malfunctions that occur.

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

Here is a listing the most reported Honeywell thermostat errors. These include the following programmable thermostats:

Display is Blank

If the monitor is clear on your programmable thermostat, you might need to replace the batteries. If that doesn’t take care of the problem or you rely on a smart thermostat, there could be a wiring malfunction.

Next, you should ensure the power is on for your furnace or air handler. Confirm the switch by the indoor system is in the “on” position.

Additionally, you should make certain all furnace cabinet or air handler doors/panels are tightly in place.

An unsecured panel may trigger the safety switch, which disconnects power to the system.

Less frequently, an empty display can indicate you need to buy a new thermostat.

Comfort Equipment Won’t Start

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

When it’s hot, confirm you put the thermostat beneath the ambient temperature. When it’s cold, make sure it’s higher. This sounds silly, but we’ve seen it take place lots of times.

Make sure the power switch by your indoor unit is in the “on” position. You should also make sure the cabinet doors or panels are closed on your furnace cabinet or air handler. An open panel can activate the safety switch, stopping power to the unit.

System still won’t turn on? Make sure circuit breakers haven’t tripped and that your HVAC equipment isn’t showing error codes.

“Cool On” or “Heat On” is Blinking

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

Then, verify it’s calling for the right equipment to start. This is typically indicated by “cool on,” “heat on” or an illustration.

If this phrase or the picture is pulsing, your thermostat is in a five-minute delay status. This feature stops your unit from harmful short cycling. This can occur if you lose power.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump requires service. Call Service Experts Heating & Air Conditioning at 330-236-4793 for assistance.
  • 168—Wi-Fi radio error. Reach Lyric technical support at 800-633-3991. 170—Internal memory error. Reach Lyric technical support at 800-633-3991.
  • 171—Set date and time. Finalize these settings so scheduling can take place.
  • 173—Thermostat temperature sensor error. Reach Lyric technical support at 800-633-3991.
  • 175—AC power restored. No action required.
  • 181/182—Install a new air filter. Clear the display by touching “dismiss” after adding a fresh filter.
  • 184—Put in a new humidifier pad. Clear the thermostat by tapping “dismiss” after installing a fresh pad filter.
  • 185—Install a new dehumidifier filter. Clear the thermostat by tapping “dismiss” after putting in a fresh filter.
  • 187—Wash or install a new ventilator filter. Clear the monitor by touching “dismiss” after installing a clean filter.
  • 188/189—Install a new UV bulb. Contact Service Experts Heating & Air Conditioning at 330-236-4793 for assistance.
  • 210—Register online for outside temperature. Get the Lyric app to finish this step and ensure accurate thermostat operation.
  • 388—Register online for remote access and exterior temperature. Download the Lyric app to do this step and ensure correct thermostat operation.
  • 399—No Internet. Verify your network settings.
  • 400—No Wi-Fi signal. Wait for the thermostat to reconnect or pick new Wi-Fi network.
  • 508—Wi-Fi not configured. Download the Lyric app and follow the procedure to link your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump must be serviced service. Call Service Experts Heating & Air Conditioning at 330-236-4793 for help.
  • 168—Wi-Fi radio error. Call Service Experts Heating & Air Conditioning at 330-236-4793 for support.
  • 170—Internal memory error. Contact Service Experts Heating & Air Conditioning at 330-236-4793 for help.
  • 171—Set date and time. Finalize these settings so scheduling can work.
  • 173—Thermostat temperature sensor error. Reach Service Experts Heating & Air Conditioning at 330-236-4793 for support.
  • 175—AC power resumed. No action necessary.
  • 177—Indoor temperature sensor error. Reach Service Experts Heating & Air Conditioning at 330-236-4793 for assistance.
  • 178—Outdoor temperature sensor error. Call Service Experts Heating & Air Conditioning at 330-236-4793 for assistance.
  • 181/182—Install a new air filter. Clear the display by tapping “dismiss” after adding a clean filter.
  • 183—Wash humidifier tank and replace water filter. Clear the display by touching “dismiss” after finishing these tasks.
  • 184—Replace humidifier pad. Clear the thermostat by hitting “dismiss” after getting a new pad filter.
  • 185—Replace dehumidifier filter. Clear the monitor by touching “dismiss” after installing a clean filter.
  • 186—Wash ventilator core. Clear the thermostat by tapping “dismiss” after completing this task.
  • 187—Wash or install a new ventilator filter. Clear the monitor by tapping “dismiss” after buying a new filter.
  • 188/189—Install a new UV bulb. Reach Service Experts Heating & Air Conditioning at 330-236-4793 for help.
  • 210—Register online for outdoor temperature. Use the Lyric app to do this step and ensure proper thermostat operation.
  • 388—Register online for remote access and outside temperature. Get the Lyric app to do this step and ensure correct thermostat operation.
  • 399—No Internet. Confirm your network settings.
  • 400—No Wi-Fi signal. Wait for the thermostat to reconnect or pick new Wi-Fi network.
  • 508—Wi-Fi not set up. Use the Lyric app and follow the steps to connect your thermostat.

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

Our Experts are Ready to Provide Support

If you’re still experiencing problems after working through the troubleshooting process, our Experts are available to help. Give us a call at 330-236-4793 and we’ll arrive as fast as we can to figure out the issue.

If you rely on a dated thermostat, today is a great time to think over a new device. Thermostat technology has come a long way in recent years Ask us for more information on how smart thermostats can make your home better while helping save on utility expenses year-round.

Contact Us