How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the best thermostat producers, and we proudly install them on a regular basis in Alliance. They’re long-lasting and dependable. Plus, Honeywell is frequently advancing its technology, resulting in more features for your family.

Still, every thermostat can run into problems every now and then. That’s why we’ve put together this useful handbook to walk you through troubleshooting. While Honeywell thermostat problems are rare, they do occur. 

While you can typically fix the majority of thermostat troubles on your own, they sometimes call for Expert help. Our HVAC professionals are ready to help when you need us. We’re merely a call away at 330-235-1260.

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

What Model of Thermostat Do I Have?

There are three types of thermostats:

  • Manual—This is the typical dial-shaped thermostat. You won’t run into error codes with this one, but it’s also the least efficient for reducing heating and cooling bills.
  • Programmable—This thermostat features a digital screen and arrows you use to determine your desired temperature. You can also use daily programs to lower the temperature when you’re gone and set it higher when you come home.
  • Smart—You won’t have to schedule any programs on this thermostat, since it learns your routine. It automatically adjusts the temperature when you or other household members are away to help you save on utility costs. You can also change the temperature anywhere via your phone or other Wi-Fi-enabled device. 

As you know the majority of technologically advanced things, there are regular malfunctions that might take place. Most of these situations don’t call for pro support and are uncomplicated enough to fix by yourself.

Common Honeywell Thermostat Issues

All thermostats have an exclusive kind of codes assigned to the problems that happen.

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

Here is a listing the most encountered Honeywell thermostat errors. These involve the following programmable thermostats:

Display is Blank

If the display is empty on your programmable thermostat, you could need to get new batteries. If that doesn’t solve the issue or you rely on a smart thermostat, there might be a wiring problem.

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

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

An unsecured panel may trip the safety switch, which cuts off power to the unit.

Less frequently, a blank monitor may indicate you should get a new thermostat.

Heating and Cooling Unit Won’t Start

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

When it’s hot, verify you set the thermostat beneath the ambient temperature. In the winter, confirm it’s higher. This sounds goofy, but we’ve seen it occur a lot of times.

Make sure the power switch by your indoor unit 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 unsecured panel can trigger the safety switch, stopping power to the unit.

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

“Cool On” or “Heat On” is Flashing

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

Then, check it’s signaling the right equipment to turn on. This is typically indicated by “cool on,” “heat on” or an icon.

If this set of words or the illustration is pulsing, your thermostat is in a five-minute delay state. This setting protects your unit from bad short cycling. This may 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 330-235-1260 for assistance.
  • 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. Contact Lyric technical support at 800-633-3991.
  • 175—AC power resumed. No action necessary.
  • 181/182—Put in a new air filter. Clear the monitor by touching “dismiss” after adding a new filter.
  • 184—Replace humidifier pad. Clear the monitor by touching “dismiss” after putting in a new pad filter.
  • 185—Replace dehumidifier filter. Clear the screen by tapping “dismiss” after adding a fresh filter.
  • 187—Rinse or install a new ventilator filter. Clear the monitor by tapping “dismiss” after putting in a clean filter.
  • 188/189—Get a new UV bulb. Ring Service Experts Heating & Air Conditioning at 330-235-1260 for support.
  • 210—Register online for exterior temperature. Use the Lyric app to complete this step and ensure proper thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Download the Lyric app to do this step and ensure proper thermostat operation.
  • 399—No Internet. Check your network settings.
  • 400—No Wi-Fi signal. Wait for the thermostat to reconnect or select new Wi-Fi network.
  • 508—Wi-Fi not configured. Download the Lyric app and follow the procedure to connect your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump needs service. Contact Service Experts Heating & Air Conditioning at 330-235-1260 for help.
  • 168—Wi-Fi radio error. Contact Service Experts Heating & Air Conditioning at 330-235-1260 for support.
  • 170—Internal memory error. Call Service Experts Heating & Air Conditioning at 330-235-1260 for help.
  • 171—Set date and time. Complete these settings so scheduling can run.
  • 173—Thermostat temperature sensor error. Reach Service Experts Heating & Air Conditioning at 330-235-1260 for help.
  • 175—AC power restored. No action needed.
  • 177—Indoor temperature sensor error. Call Service Experts Heating & Air Conditioning at 330-235-1260 for support.
  • 178—Outdoor temperature sensor error. Contact Service Experts Heating & Air Conditioning at 330-235-1260 for help.
  • 181/182—Replace air filter. Clear the screen by touching “dismiss” after adding a clean filter.
  • 183—Rinse humidifier tank and replace water filter. Clear the display by hitting “dismiss” after finishing these steps.
  • 184—Replace humidifier pad. Clear the screen by touching “dismiss” after getting a new pad filter.
  • 185—Replace dehumidifier filter. Clear the screen by tapping “dismiss” after adding a clean filter.
  • 186—Rinse ventilator core. Clear the monitor 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—Get a new UV bulb. Get in touch with Service Experts Heating & Air Conditioning at 330-235-1260 for assistance.
  • 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 outdoor temperature. Get 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 configured. Use the Lyric app and follow the process to connect your thermostat.

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

Our Experts are Ready to Provide Assistance

If you’re still having issues after trying the troubleshooting list, our Experts are available to support you. Reach us at 330-235-1260 and we’ll come to your house quickly to diagnose the malfunction.

If you rely on a dated thermostat, now is a fantastic time to think about a new device. Thermostat technology has gotten better over the last few years. Ask us for more information on how smart thermostats can make your home more convenient while helping save on heating and cooling costs all year.