How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the top thermostat brands, and we proudly install them on a regular basis in the U.S.. They’re durable and dependable. Also, Honeywell is frequently enhancing its technology, resulting in more features for your residence.

However, each thermostat can run into troubles now and again. That’s why we’ve put together this informative guidebook to run through troubleshooting. While Honeywell thermostat troubleshooting problems are rare, they do pop up.

While you can typically fix the majority of thermostat issues on your own, they often call for Expert help. Our home comfort professionals are ready to support you when you need us. We’re just a call away at 866-397-3787.

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

What Kind of Thermostat Do I Have?

There are three models of thermostats:

  • Manual—This is the classic dial-shaped thermostat. You won’t run into error codes with this one, but it’s also the least efficient for reducing energy bills.
  • Programmable—This thermostat has a digital screen and arrows you press to choose your desired temperature. You can also use daily programs to lower the temperature when you’re at work and raise it when you return.
  • Smart—You won’t have to set any programs on this thermostat, as it learns your routine. It instinctively raises and lowers the temperature when you or other household members are gone to help you save on utility bills. You can also adjust the temperature anywhere on your phone or other Wi-Fi-enabled device.

As you know most technologically advanced solutions, there are common glitches that might occur. Many of these issues don’t call for professional help and are easy to fix on your own.

Common Honeywell Thermostat Troubleshooting Issues

Every Honeywell thermostat has an exclusive group of codes matching the problems that occur.

Think how easy it can be to restore a computer by restarting it. In many instances, diagnosing a thermostat can be just as easy.

Here is a listing the most common Honeywell thermostat errors. These are applicable to the following programmable thermostats:

Display is Blank

If the display is blank on your programmable thermostat, you may need to replace the batteries. If that doesn’t fix the malfunction or you have a smart thermostat, there might be a wiring malfunction.

Next, you should make sure the power is enabled for your furnace or air handler. Make sure the switch close to the indoor equipment is switched “up”.

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

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

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

Heating and Cooling Equipment Won’t Start

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

During warm weather, confirm you put the thermostat lower than the current temperature. In the winter, confirm it’s higher. This sounds absurd, but we’ve seen it happen many times.

Ensure the power switch by your indoor equipment is in the “on” position. You should also check the cabinet doors or panels are closed on your furnace cabinet or air handler. A loose panel can activate the safety switch, cutting off current to the unit.

Heating or cooling still won’t run? Make sure circuit breakers haven’t turned off and that your HVAC system isn’t displaying error codes.

“Cool On” or “Heat On” is Flickering

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

Then, make sure it’s signaling the correct equipment to run. This is usually shown by “cool on,” “heat on” or an illustration.

If these words or the illustration is blinking, your thermostat is in a five-minute delay status. This mode keeps your system from damaging short cycling. This can occur if your power is interrupted.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump needs service. Call Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for assistance.
  • 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. Complete 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 thermostat by hitting “dismiss” after adding a clean filter.
  • 184—Replace humidifier pad. Clear the monitor by hitting “dismiss” after installing a new pad filter.
  • 185—Replace dehumidifier filter. Clear the monitor by hitting “dismiss” after putting in a new filter.
  • 187—Wash or put in a new ventilator filter. Clear the monitor by hitting “dismiss” after putting in a fresh filter.
  • 188/189—Install a new UV bulb. Ring Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for help.
  • 210—Register online for outside temperature. Download the Lyric app to complete this step and ensure correct thermostat operation.
  • 388—Register online for remote access and exterior temperature. Use the Lyric app to finish 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 choose new Wi-Fi network.
  • 508—Wi-Fi not configured. Use the Lyric app and follow the procedure to configure your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005)

  • 164—Heat pump requires service. Reach Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for help.
  • 168—Wi-Fi radio error. Reach Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for assistance.
  • 170—Internal memory error. Contact Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for assistance.
  • 171—Set date and time. Finish these settings so scheduling can work.
  • 173—Thermostat temperature sensor error. Contact Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for support.
  • 175—AC power resumed. No action needed.
  • 177—Indoor temperature sensor error. Call Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for help.
  • 178—Outdoor temperature sensor error. Reach Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for help.
  • 181/182—Install a new air filter. Clear the display by touching “dismiss” after adding a clean filter.
  • 183—Wash humidifier tank and replace water filter. Clear the thermostat by tapping “dismiss” after completing these tasks.
  • 184—Get a new humidifier pad. Clear the monitor by hitting “dismiss” after adding a new pad filter.
  • 185—Get a new dehumidifier filter. Clear the display by tapping “dismiss” after putting in a fresh filter.
  • 186—Rinse ventilator core. Clear the thermostat by touching “dismiss” after finishing this task.
  • 187—Rinse or get a new ventilator filter. Clear the screen by touching “dismiss” after getting a new filter.
  • 188/189—Install a new UV bulb. Contact Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for support.
  • 210—Register online for exterior temperature. Get the Lyric app to finish this step and ensure correct thermostat operation.
  • 388—Register online for remote access and exterior temperature. Use the Lyric app to do this step and ensure proper 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 connected. Download the Lyric app and follow the steps to connect your thermostat.

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

Our Experts are Here to Provide Assistance

If you’re still running into troubles after going through the troubleshooting list, our Experts are available to support you. Call us at 866-397-3787 and we’ll arrive as fast as we can to diagnose the problem.

If you rely on an older thermostat, today is a great time to think about a replacement. Thermostat technology has gotten better in recent years Ask us for more information on how smart thermostats can make your residence comfier while helping save on energy bills throughout the year.