How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the leading thermostat producers, and we proudly install them on a usual basis in Toronto. They’re sturdy and dependable. In addition, Honeywell is frequently enhancing its technology, resulting in more features for your house.

Still, all thermostats can run into issues from time to time. That’s why we’ve prepared this informative guidebook to walk you through troubleshooting.

While you can often solve many thermostat issues by yourself, they sometimes call for Expert support. Our home comfort professionals are ready to support you when you need us. We’re only a call away at 905-453-6700.

Let’s begin the process by figuring out what type of thermostat your residence has.

What Type of Thermostat Do I Have?

There are three kinds of thermostats:

  • Manual—This is the typical dial-shaped thermostat. You won’t have error codes with this kind, but it’s also the least efficient for reducing energy costs.
  • Programmable—This thermostat features a digital screen and arrows you touch to determine your desired temperature. You can also choose daily programs to reduce the temperature when you’re away and increase it when you come home.
  • Smart—You won’t have to make any programs on this thermostat, as it learns your day. It automatically raises and lowers the temperature when you or family members are out and about to help you save on energy expenses. You can also change the temperature anywhere via your phone or other Wi-Fi-enabled device. 

As is the case with the majority of technologically advanced solutions, there are regular malfunctions that may occur. The majority of of these problems don’t require professional support and are uncomplicated enough to solve alone.

Common Honeywell Thermostat Problems

Each thermostat has a special kind of codes matching the malfunctions that happen.

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

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

Display is Blank

If the display is clear on your programmable thermostat, you may need to replace the batteries. If that doesn’t fix the issue or you use a smart thermostat, there may be a wiring problem.

Next, you should check the power is flowing for your furnace or air handler. Verify the switch close to the indoor system is switched “on”.

In addition to that, you should make certain all furnace cabinet or air handler doors/panels are securely fastened.

An unsecured panel may trip the safety switch, which stops power to the equipment.

Less frequently, a blank monitor might indicate you should replace your thermostat.

Heating and Cooling System Won’t Run

Make sure that your thermostat is switched to “cool” or “heat,” not “off.”

During warm weather, verify you schedule the thermostat below the room temperature. When it’s cool, make sure it’s higher. This sounds absurd, but we’ve seen it happen lots of times.

Ensure the power switch close to your indoor system 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 trip the safety switch, diverting current to the equipment.

Heating or cooling still won’t run? Verify circuit breakers haven’t flipped and that your HVAC equipment isn’t showing error codes.

“Cool On” or “Heat On” is Flashing

First, ensure your thermostat is switched to “cool” or “heat.”

Then, make sure it’s calling for the appropriate unit to start. This is usually indicated by “cool on,” “heat on” or an icon.

If this phrase or the icon is blinking, your thermostat is in a five-minute delay state. This mode keeps your system from harmful short cycling. This could 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 Commercial HVAC at 905-453-6700 for help.
  • 168—Wi-Fi radio error. Reach Lyric technical support at 800-633-3991. 170—Internal memory error. Call Lyric technical support at 800-633-3991.
  • 171—Set date and time. Finish these settings so scheduling can run.
  • 173—Thermostat temperature sensor error. Call 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 adding a new filter.
  • 184—Install a new humidifier pad. Clear the display by hitting “dismiss” after installing a clean pad filter.
  • 185—Replace dehumidifier filter. Clear the thermostat by tapping “dismiss” after installing a new filter.
  • 187—Wash or install a new ventilator filter. Clear the monitor by tapping “dismiss” after adding a clean filter.
  • 188/189—Get a new UV bulb. Contact Service Experts Commercial HVAC at 905-453-6700 for assistance.
  • 210—Register online for outdoor temperature. Download the Lyric app to complete this step and ensure correct thermostat operation.
  • 388—Register online for remote access and outside temperature. Get the Lyric app to finish 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 set. Use the Lyric app and follow the procedure to configure your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump requires service. Contact Service Experts Commercial HVAC at 905-453-6700 for help.
  • 168—Wi-Fi radio error. Reach Service Experts Commercial HVAC at 905-453-6700 for support.
  • 170—Internal memory error. Contact Service Experts Commercial HVAC at 905-453-6700 for help.
  • 171—Set date and time. Finish these settings so scheduling can run.
  • 173—Thermostat temperature sensor error. Call Service Experts Commercial HVAC at 905-453-6700 for help.
  • 175—AC power reconnected. No action needed.
  • 177—Indoor temperature sensor error. Call Service Experts Commercial HVAC at 905-453-6700 for support.
  • 178—Outdoor temperature sensor error. Contact Service Experts Commercial HVAC at 905-453-6700 for help.
  • 181/182—Get a new air filter. Clear the screen by hitting “dismiss” after putting in a new filter.
  • 183—Wash humidifier tank and add a new water filter. Clear the screen by hitting “dismiss” after completing these tasks.
  • 184—Get a new humidifier pad. Clear the display by touching “dismiss” after installing pad filter.
  • 185—Get a new dehumidifier filter. Clear the thermostat by tapping “dismiss” after installing a new filter.
  • 186—Clean ventilator core. Clear the monitor by hitting “dismiss” after completing this task.
  • 187—Clean or get a new ventilator filter. Clear the screen by hitting “dismiss” after buying a new filter.
  • 188/189—Get a new UV bulb. Reach Service Experts Commercial HVAC at 905-453-6700 for help.
  • 210—Register online for exterior temperature. Get the Lyric app to complete this step and ensure proper thermostat operation.
  • 388—Register online for remote access and outside temperature. Download the Lyric app to complete this step and ensure accurate 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. Download the Lyric app and follow the procedures to connect your thermostat.

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

Our Experts are Available to Provide Support

If you’re still having issues after going through the troubleshooting steps, our pros are here to assist you. Give us a call at 905-453-6700 and we’ll be out as fast as we can to determine the malfunction.

If you use an aging thermostat, right now is a good time to consider a new thermostat. Thermostat technology has advanced over the last few years. Ask us for more info on how smart thermostats can make your house better while helping save on energy bills all year.

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