How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the best thermostat manufacturers, and we proudly install them on a regular basis in Memphis. They’re durable and reliable. In addition, Honeywell is regularly improving its technology, offering more features for your house.

Nevertheless, all thermostats can run into errors at times. That’s why we’ve compiled this helpful guidebook to walk you through troubleshooting. While Honeywell thermostat problems are rare, they do occur. 

While you can typically repair most thermostat troubles by yourself, they occasionally call for Expert help. Our home comfort pros are here to support you when you need us. We’re only a call away at 901-235-1196.

Let’s get started with the process by determining what type of thermostat your residence has.

What Model of Thermostat Do I Have?

There are three types of thermostats:

  • Manual—This is the classic dial-shaped thermostat. You won’t have error codes with this one, but it’s also the least efficient for reducing heating and cooling bills.
  • Programmable—This thermostat has a digital screen and arrows you use to choose your desired temperature. You can also use daily programs to reduce the temperature when you’re gone and set it higher when you get back.
  • Smart—You won’t have to set any programs on this thermostat, since it learns your schedule. It intuitively changes the temperature when you or other household members are out and about to help you save on heating and cooling expenses. You can also raise or lower the temperature anywhere via your phone or other Wi-Fi-enabled device. 

As is the case with many technologically advanced things, there are regular glitches that may take place. Most of these troubles don’t call for pro help and are uncomplicated enough to fix alone.

Common Honeywell Thermostat Issues

Each thermostat has an exclusive kind of codes assigned to the troubles that happen.

Think how easy it can be to restore a computer by restarting it. Many times, correcting a thermostat can be just as easy.

Here are some of the most encountered Honeywell thermostat issues. These involve the following programmable thermostats:

Display is Blank

If the screen is clear on your programmable thermostat, you may need to get new batteries. If that doesn’t solve the malfunction or you have a smart thermostat, there could be a wiring issue.

Next, you should make sure the power is flowing for your furnace or air handler. Confirm the switch by the indoor unit is switched “up”.

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

A loose panel may trip the safety switch, which stops power to the equipment.

Infrequently, an empty screen might signify you need to get a new thermostat.

Heating and Cooling Equipment Won’t Work

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

When it’s hot, confirm you put the thermostat lower than the room temperature. In the winter, make sure it’s higher. This sounds absurd, but we’ve seen it occur a lot of times.

Confirm the power switch near your indoor system is in the “on” position. You should also comfirm the cabinet doors or panels are closed on your furnace cabinet or air handler. An unsecured panel can trip the safety switch, diverting power to the system.

Unit still won’t run? Make sure circuit breakers haven’t flipped and that your HVAC equipment isn’t experiencing error codes.

“Cool On” or “Heat On” is Flickering

To start, make sure your thermostat is switched to “cool” or “heat.”

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

If this set of words or the picture is flashing, your thermostat is in a five-minute delay status. This setting stops your system from damaging short cycling. This could take place if your power is interrupted.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump must be serviced. Call Service Experts Heating & Air Conditioning at 901-235-1196 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. Finish 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 needed.
  • 181/182—Replace air filter. Clear the display by tapping “dismiss” after adding a new filter.
  • 184—Replace humidifier pad. Clear the thermostat by touching “dismiss” after adding a new pad filter.
  • 185—Install a new dehumidifier filter. Clear the screen by hitting “dismiss” after installing a new filter.
  • 187—Rinse or put in a new ventilator filter. Clear the thermostat by tapping “dismiss” after putting in a clean filter.
  • 188/189—Install a new UV bulb. Ring Service Experts Heating & Air Conditioning at 901-235-1196 for assistance.
  • 210—Register online for outdoor temperature. Get the Lyric app to complete this step and ensure correct thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Download the Lyric app to complete this step and ensure accurate 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. Use the Lyric app and follow the procedure to link your thermostat.

For more specifics, view 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 901-235-1196 for support.
  • 168—Wi-Fi radio error. Call Service Experts Heating & Air Conditioning at 901-235-1196 for support.
  • 170—Internal memory error. Contact Service Experts Heating & Air Conditioning at 901-235-1196 for assistance.
  • 171—Set date and time. Complete these settings so scheduling can work.
  • 173—Thermostat temperature sensor error. Contact Service Experts Heating & Air Conditioning at 901-235-1196 for help.
  • 175—AC power reconnected. No action required.
  • 177—Indoor temperature sensor error. Call Service Experts Heating & Air Conditioning at 901-235-1196 for help.
  • 178—Outdoor temperature sensor error. Call Service Experts Heating & Air Conditioning at 901-235-1196 for support.
  • 181/182—Install a new air filter. Clear the monitor by touching “dismiss” after adding a fresh filter.
  • 183—Clean humidifier tank and add a new water filter. Clear the thermostat by touching “dismiss” after doing these steps.
  • 184—Replace humidifier pad. Clear the display by touching “dismiss” after getting a new pad filter.
  • 185—Get a new dehumidifier filter. Clear the screen by touching “dismiss” after adding a clean filter.
  • 186—Wash ventilator core. Clear the screen by touching “dismiss” after doing this task.
  • 187—Wash or get a new ventilator filter. Clear the monitor by touching “dismiss” after installing a new filter.
  • 188/189—Install a new UV bulb. Contact Service Experts Heating & Air Conditioning at 901-235-1196 for assistance.
  • 210—Register online for exterior temperature. Get the Lyric app to do this step and ensure accurate thermostat operation.
  • 388—Register online for remote access and exterior temperature. Use the Lyric app to complete this step and ensure correct thermostat operation.
  • 399—No Internet. Check 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. Download the Lyric app and follow the procedures to connect your thermostat.

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

Our Experts are Ready to Provide Support

If you’re still running into issues after trying the troubleshooting list, our Experts are here to help. Call us at 901-235-1196 and we’ll be out as fast as we can to determine the malfunction.

If you rely on an older thermostat, now is a fantastic time to consider a replacement. Thermostat technology has come a long way lately Ask us for more information on how smart thermostats can make your home more convenient while helping save on utility costs year-round.

Contact Us