How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the best thermostat manufacturers, and we proudly install them on a regular basis in Hurricane. They’re durable and dependable. Also, Honeywell is frequently improving its technology, bringing more features for your household.

Nevertheless, all thermostats can have troubles at one time or another. Due to this, we’ve compiled this helpful manual to run through troubleshooting.

While you can usually repair many thermostat troubles on your own, they often need Expert assistance. Our HVAC professionals are here to help when you need us. We’re just a call away at 304-760-5088.

Let’s get started with the process by determining what model of thermostat your home 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 have error codes with this one, but it’s also the least efficient for lowering energy expenses.
  • Programmable—This thermostat features a digital screen and arrows you use to choose your desired temperature. You can also use daily programs to decrease the temperature when you’re gone and set it higher when you return.
  • Smart—You won’t have to make any programs on this thermostat, as it picks up on your day. It intuitively raises and lowers the temperature when you or other household members are gone to help you save on energy costs. You can also change the temperature anywhere via your phone or other Wi-Fi-enabled device. 

As you know most technologically advanced products, there are regular problems that might occur. Many of these situations don’t call for pro assistance and are simple to repair by yourself.

Common Honeywell Thermostat Problems

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

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

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

Display is Blank

If the monitor is clear on your programmable thermostat, you could need to install new batteries. If that doesn’t take care of the problem or you rely on a smart thermostat, there might be a wiring malfunction.

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

Additionally, you should make sure all furnace cabinet or air handler doors/panels are tightly in place.

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

Less frequently, a clear screen may mean you need to buy a new thermostat.

Comfort Unit Won’t Work

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

In the summer, verify you schedule the thermostat beneath the ambient temperature. When it’s cold, confirm it’s higher. This sounds silly, but we’ve seen it occur lots of times.

Make sure the power switch close to your indoor equipment is in the “on” position. You should also check the cabinet doors or panels are tight on your furnace cabinet or air handler. An unsecured panel can trip the safety switch, stopping power to the unit.

Equipment still won’t run? Verify circuit breakers haven’t tripped and that your HVAC system isn’t showing error codes.

“Cool On” or “Heat On” is Flickering

To start, ensure your thermostat is set to “cool” or “heat.”

Then, verify it’s signaling the right equipment to turn on. This is typically shown by “cool on,” “heat on” or a picture.

If this phrase or the picture is flashing, your thermostat is in a five-minute delay state. This mode protects your equipment from damaging short cycling. This could happen if you lose electricity.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump must be serviced. Call Teays Valley Service Experts at 304-760-5088 for assistance.
  • 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. Complete these settings so scheduling can occur.
  • 173—Thermostat temperature sensor error. Reach Lyric technical support at 800-633-3991.
  • 175—AC power resumed. No action needed.
  • 181/182—Replace air filter. Clear the thermostat by hitting “dismiss” after installing a clean filter.
  • 184—Replace humidifier pad. Clear the display by touching “dismiss” after adding a new pad filter.
  • 185—Replace dehumidifier filter. Clear the thermostat by hitting “dismiss” after adding a clean filter.
  • 187—Wash or put in a new ventilator filter. Clear the thermostat by touching “dismiss” after installing a new filter.
  • 188/189—Replace UV bulb. Contact Teays Valley Service Experts at 304-760-5088 for assistance.
  • 210—Register online for exterior temperature. Use 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 do this step and ensure accurate thermostat operation.
  • 399—No Internet. Confirm your network settings.
  • 400—No Wi-Fi signal. Wait for the thermostat to reconnect or choose new Wi-Fi network.
  • 508—Wi-Fi not set up. Download the Lyric app and follow the procedure to connect your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump must be serviced service. Call Teays Valley Service Experts at 304-760-5088 for assistance.
  • 168—Wi-Fi radio error. Contact Teays Valley Service Experts at 304-760-5088 for help.
  • 170—Internal memory error. Reach Teays Valley Service Experts at 304-760-5088 for assistance.
  • 171—Set date and time. Finish these settings so scheduling can work.
  • 173—Thermostat temperature sensor error. Call Teays Valley Service Experts at 304-760-5088 for help.
  • 175—AC power restored. No action necessary.
  • 177—Indoor temperature sensor error. Call Teays Valley Service Experts at 304-760-5088 for assistance.
  • 178—Outdoor temperature sensor error. Call Teays Valley Service Experts at 304-760-5088 for assistance.
  • 181/182—Replace air filter. Clear the monitor by hitting “dismiss” after installing a new filter.
  • 183—Wash humidifier tank and install a new water filter. Clear the monitor by tapping “dismiss” after doing these steps.
  • 184—Install a new humidifier pad. Clear the display by tapping “dismiss” after getting a new pad filter.
  • 185—Replace dehumidifier filter. Clear the screen by touching “dismiss” after putting in a fresh filter.
  • 186—Clean ventilator core. Clear the display by touching “dismiss” after completing this task.
  • 187—Wash or install a new ventilator filter. Clear the monitor by tapping “dismiss” after installing a new filter.
  • 188/189—Get a new UV bulb. Contact Teays Valley Service Experts at 304-760-5088 for assistance.
  • 210—Register online for outside 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 accurate 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. Use the Lyric app and follow the steps to connect your thermostat.

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

Our Experts are Ready to Provide Support

If you’re still having troubles after going through the troubleshooting steps, our Experts are available to assist you. Give us a call at 304-760-5088 and we’ll come to your house quickly to determine the malfunction.

If you rely on an aging thermostat, now is a great time to think over a new thermostat. Thermostat technology has come a long way over the last few years. Ask us for more details on how smart thermostats can make your home comfier while helping save on energy expenses throughout the year.

Contact Us