How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the leading thermostat producers, and we proudly install them on a frequent basis in Dayton. They’re durable and reliable. Also, Honeywell is frequently updating its technology, bringing more features for your home.

Still, all thermostats can have troubles every so often. That’s why we’ve compiled this helpful guide to go over troubleshooting.

While you can typically repair most thermostat issues on your own, they occasionally require Expert help. Our HVAC pros are here to assist you when you need us. We’re only a call away at 937-503-7896.

Let’s begin the process by determining what type of thermostat your house has.

What Kind of Thermostat Do I Have?

There are three kinds of thermostats:

  • Manual—This is the typical dial-shaped thermostat. You won’t run into error codes with this kind, but it’s also the least efficient for reducing heating and cooling expenses.
  • Programmable—This thermostat includes a digital screen and arrows you touch to determine your desired temperature. You can also choose daily programs to decrease the temperature when you’re gone and set it higher when you get back.
  • Smart—You won’t have to make any programs on this thermostat, since it adjusts to your schedule. It automatically changes the temperature when you or family members are away to help you save on energy bills. You can also raise or lower the temperature anywhere on your phone or other Wi-Fi-enabled device. 

As you know many technologically advanced solutions, there are several problems that can occur. Many of these troubles don’t need professional assistance and are uncomplicated enough to repair on your own.

Common Honeywell Thermostat Problems

Each thermostat has a unique kind of codes assigned to the troubles that happen.

Think how uncomplicated it can be to fix a computer by restarting it. In many instances, troubleshooting a thermostat can be just as easy.

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

Display is Blank

If the display is clear on your programmable thermostat, you may need to get new batteries. If that doesn’t take care of the trouble or you rely on a smart thermostat, there may be a wiring issue.

Next, you should ensure the power is enabled for your furnace or air handler. Confirm the switch near the indoor system is switched “up”.

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

An unsecured panel may activate the safety switch, which disconnects power to the unit.

While it’s less common, a blank display may signify you will need to replace your thermostat.

Heating and Cooling Unit Won’t Run

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

In the summer, confirm you set the thermostat beneath the room temperature. In the winter, make sure it’s higher. This sounds goofy, but we’ve seen it happen lots of times.

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

Unit still won’t turn on? Verify circuit breakers haven’t flipped and that your HVAC equipment isn’t showing error codes.

“Cool On” or “Heat On” is Flickering

To begin, confirm your thermostat is switched to “cool” or “heat.”

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

If these words or the icon is flashing, your thermostat is in a five-minute delay mode. This mode keeps your equipment from damaging short cycling. This could happen if your power is interrupted.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump requires service. Call Stevenson Service Experts at 937-503-7896 for support.
  • 168—Wi-Fi radio error. Call Lyric technical support at 800-633-3991. 170—Internal memory error. Call Lyric technical support at 800-633-3991.
  • 171—Set date and time. Complete these settings so scheduling can run.
  • 173—Thermostat temperature sensor error. Reach Lyric technical support at 800-633-3991.
  • 175—AC power restarted. No action required.
  • 181/182—Replace air filter. Clear the monitor by touching “dismiss” after installing a fresh filter.
  • 184—Install a new humidifier pad. Clear the thermostat by tapping “dismiss” after adding a fresh pad filter.
  • 185—Replace dehumidifier filter. Clear the screen by hitting “dismiss” after installing a new filter.
  • 187—Clean or install a new ventilator filter. Clear the screen by touching “dismiss” after adding a clean filter.
  • 188/189—Install a new UV bulb. Call Stevenson Service Experts at 937-503-7896 for help.
  • 210—Register online for outdoor temperature. Use 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 proper 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 set up. Use the Lyric app and follow the procedure to configure your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump requires service. Contact Stevenson Service Experts at 937-503-7896 for assistance.
  • 168—Wi-Fi radio error. Reach Stevenson Service Experts at 937-503-7896 for help.
  • 170—Internal memory error. Contact Stevenson Service Experts at 937-503-7896 for assistance.
  • 171—Set date and time. Finish these settings so scheduling can work.
  • 173—Thermostat temperature sensor error. Call Stevenson Service Experts at 937-503-7896 for assistance.
  • 175—AC power restored. No action necessary.
  • 177—Indoor temperature sensor error. Reach Stevenson Service Experts at 937-503-7896 for assistance.
  • 178—Outdoor temperature sensor error. Call Stevenson Service Experts at 937-503-7896 for assistance.
  • 181/182—Get a new air filter. Clear the display by tapping “dismiss” after installing a fresh filter.
  • 183—Rinse humidifier tank and install a new water filter. Clear the display by touching “dismiss” after completing these tasks.
  • 184—Get a new humidifier pad. Clear the monitor by tapping “dismiss” after getting a new pad filter.
  • 185—Get a new dehumidifier filter. Clear the screen by tapping “dismiss” after putting in a clean filter.
  • 186—Rinse ventilator core. Clear the thermostat by touching “dismiss” after finishing this task.
  • 187—Clean or install a new ventilator filter. Clear the monitor by hitting “dismiss” after installing a new filter.
  • 188/189—Add a new UV bulb. Contact Stevenson Service Experts at 937-503-7896 for support.
  • 210—Register online for outside temperature. Use the Lyric app to finish this step and ensure accurate thermostat operation.
  • 388—Register online for remote access and exterior temperature. Use 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 configured. Download the Lyric app and follow the process to connect your thermostat.

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

Our Experts are Ready to Help

If you’re still experiencing troubles after going through the troubleshooting steps, our Experts are available to assist you. Reach us at 937-503-7896 and we’ll come to your house quickly to determine the issue.

If you use a dated thermostat, right now is a fantastic time to think about a new device. Thermostat technology has gotten better lately Ask us for more details on how smart thermostats can make your home comfier while helping save on utility expenses year-round.

Contact Us