How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the best thermostat brands, and we proudly install them on a usual basis in Rochester. They’re long-lasting and dependable. In addition, Honeywell is constantly improving its technology, bringing more features for your home.

Still, all thermostats can run into problems now and then. As a result, we’ve prepared this useful guidebook to go over troubleshooting. While Honeywell thermostat problems are rare, they do pop up. 

While you can usually solve most thermostat problems on your own, they often call for Expert assistance. Our heating and cooling professionals are here to support you when you need us. We’re just a call away at 603-923-4570.

Let’s begin the process by determining what model of thermostat your home has.

What Type of Thermostat Do I Have?

There are three kinds of thermostats:

  • Manual—This is the older dial-shaped thermostat. You won’t have error codes with this kind, but it’s also the least efficient for lowering energy expenses.
  • Programmable—This thermostat has a digital screen and arrows you press to set your desired temperature. You can also set daily programs to decrease the temperature when you’re away and raise it when you come home.
  • Smart—You won’t have to make any programs on this thermostat, as it adjusts to your day. It instinctively raises and lowers the temperature when you or other household members are away to help you save on utility expenses. You can also adjust the temperature anywhere on your phone or other Wi-Fi-enabled device. 

As you know the majority of technologically advanced solutions, there are several malfunctions that may happen. The majority of of these situations don’t call for professional help and are uncomplicated enough to fix alone.

Common Honeywell Thermostat Troubles

Each thermostat has a special group of codes assigned to the glitches that occur.

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

Here is a guide to the most encountered Honeywell thermostat problems. These apply to the following programmable thermostats:

Display is Blank

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

Next, you should make sure the power is flowing for your furnace or air handler. Make sure the switch close to 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.

A panel that isn’t tight may activate the safety switch, which stops power to the equipment.

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

Heating and Cooling Equipment Won’t Work

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

When it’s hot, confirm you schedule the thermostat beneath the ambient temperature. When it’s cool, confirm it’s higher. This sounds goofy, but we’ve seen it occur many times.

Ensure the power switch by your indoor equipment 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 activate the safety switch, stopping power to the equipment.

Unit still won’t start? Make sure circuit breakers haven’t tripped and that your HVAC system isn’t showing error codes.

“Cool On” or “Heat On” is Blinking

First, confirm your thermostat is on “cool” or “heat.”

Then, make sure it’s telling the right equipment to turn on. This is usually shown by “cool on,” “heat on” or an icon.

If these words or the picture is flashing, your thermostat is in a five-minute delay status. This setting stops your equipment from harmful short cycling. This can happen if your power is interrupted.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump requires service. Call Strogen's Service Experts at 603-923-4570 for support.
  • 168—Wi-Fi radio error. Call Lyric technical support at 800-633-3991. 170—Internal memory error. Contact Lyric technical support at 800-633-3991.
  • 171—Set date and time. Finalize these settings so scheduling can occur.
  • 173—Thermostat temperature sensor error. Contact Lyric technical support at 800-633-3991.
  • 175—AC power restored. No action required.
  • 181/182—Replace air filter. Clear the display by tapping “dismiss” after putting in a fresh filter.
  • 184—Install a new humidifier pad. Clear the monitor by tapping “dismiss” after putting in a new pad filter.
  • 185—Install a new dehumidifier filter. Clear the screen by tapping “dismiss” after installing a fresh filter.
  • 187—Clean or put in a new ventilator filter. Clear the display by hitting “dismiss” after adding a clean filter.
  • 188/189—Replace UV bulb. Ring Strogen's Service Experts at 603-923-4570 for support.
  • 210—Register online for outside temperature. Use the Lyric app to complete this step and ensure proper thermostat operation.
  • 388—Register online for remote access and exterior temperature. Get the Lyric app to complete 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 select new Wi-Fi network.
  • 508—Wi-Fi not set up. Download the Lyric app and follow the process to link your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump must be serviced service. Reach Strogen's Service Experts at 603-923-4570 for help.
  • 168—Wi-Fi radio error. Call Strogen's Service Experts at 603-923-4570 for support.
  • 170—Internal memory error. Call Strogen's Service Experts at 603-923-4570 for support.
  • 171—Set date and time. Finish these settings so scheduling can work.
  • 173—Thermostat temperature sensor error. Contact Strogen's Service Experts at 603-923-4570 for assistance.
  • 175—AC power resumed. No action necessary.
  • 177—Indoor temperature sensor error. Contact Strogen's Service Experts at 603-923-4570 for assistance.
  • 178—Outdoor temperature sensor error. Call Strogen's Service Experts at 603-923-4570 for help.
  • 181/182—Replace air filter. Clear the display by touching “dismiss” after installing a clean filter.
  • 183—Wash humidifier tank and add a new water filter. Clear the screen by tapping “dismiss” after finishing these procedures.
  • 184—Get a new humidifier pad. Clear the screen by touching “dismiss” after adding a new pad filter.
  • 185—Replace dehumidifier filter. Clear the display by touching “dismiss” after installing a clean filter.
  • 186—Clean ventilator core. Clear the display by touching “dismiss” after doing this task.
  • 187—Clean or get a new ventilator filter. Clear the monitor by touching “dismiss” after buying a new filter.
  • 188/189—Add a new UV bulb. Contact Strogen's Service Experts at 603-923-4570 for help.
  • 210—Register online for outside temperature. Download the Lyric app to finish this step and ensure proper thermostat operation.
  • 388—Register online for remote access and exterior temperature. Get the Lyric app to complete 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 pick new Wi-Fi network.
  • 508—Wi-Fi not configured. Download the Lyric app and follow the process to connect your thermostat.

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

Our Experts are Available to Provide Assistance

If you’re still running into troubles after trying the troubleshooting process, our Experts are here to support you. Reach us at 603-923-4570 and we’ll come to your house quickly to figure out the problem.

If you rely on a dated thermostat, right now is a great time to think about a new device. Thermostat technology has advanced lately Ask us for more information on how smart thermostats can make your home comfier while helping save on utility costs throughout the year.

Contact Us