How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the best thermostat manufacturers, and we proudly install them on a frequent basis in Nashville. They’re durable and reliable. Also, Honeywell is frequently updating its technology, resulting in more features for your household.

Still, each thermostat can experience problems now and then. As a result, we’ve prepared this valuable manual to walk you through troubleshooting.

While you can usually solve the majority of thermostat problems by yourself, they sometimes call for Expert assistance. Our HVAC professionals are available to support you when you need us. We’re merely a call away at 615-953-9885.

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

What Type of Thermostat Do I Have?

There are three types of thermostats:

  • Manual—This is the classic dial-shaped thermostat. You won’t have error codes with this kind, but it’s also the least efficient for reducing utility costs.
  • Programmable—This thermostat includes a digital screen and arrows you touch to set your desired temperature. You can also use daily programs to reduce the temperature when you’re away and increase it when you return.
  • Smart—You won’t have to schedule any programs on this thermostat, because it learns your day. It instinctively changes the temperature when you or family members are out and about to help you save on utility bills. You can also raise or lower the temperature anywhere on your phone or other Wi-Fi-enabled device. 

As is the case with most technologically advanced solutions, there are several malfunctions that may happen. Many of these troubles don’t require professional support and are easy to repair by yourself.

Common Honeywell Thermostat Problems

Every thermostat has an exclusive set of codes that correspond to the troubles that occur.

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

Here are some of the most encountered Honeywell thermostat problems. These are applicable to the following programmable thermostats:

Display is Blank

If the display is clear on your programmable thermostat, you may need to put in new batteries. If that doesn’t fix the problem or you rely on a smart thermostat, there may be a wiring malfunction.

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

Also, you should make certain all furnace cabinet or air handler doors/panels are sturdily secured.

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

While it’s less common, a clear monitor might indicate you should replace your thermostat.

Heating and Cooling System Won’t Turn On

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

When it’s hot, make sure you set the thermostat lower than the ambient temperature. When it’s cold, confirm it’s higher. This sounds silly, but we’ve seen it take place lots of times.

Ensure the power switch close to 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 open panel can trigger the safety switch, cutting off current to the system.

Heating or cooling still won’t start? Confirm circuit breakers haven’t flipped and that your HVAC unit isn’t displaying error codes.

“Cool On” or “Heat On” is Blinking

To start, check your thermostat is on “cool” or “heat.”

Then, verify it’s calling for the appropriate system to start. This is usually indicated by “cool on,” “heat on” or a picture.

If this set of words or the picture is blinking, your thermostat is in a five-minute delay status. This setting protects your system from bad short cycling. This may take place if you lose power.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump requires service. Call Donelson Air Service Experts at 615-953-9885 for help.
  • 168—Wi-Fi radio error. Contact Lyric technical support at 800-633-3991. 170—Internal memory error. Call Lyric technical support at 800-633-3991.
  • 171—Set date and time. Finalize these settings so scheduling can occur.
  • 173—Thermostat temperature sensor error. Reach Lyric technical support at 800-633-3991.
  • 175—AC power restarted. No action required.
  • 181/182—Replace air filter. Clear the display by touching “dismiss” after installing a new filter.
  • 184—Install a new humidifier pad. Clear the screen by hitting “dismiss” after installing a fresh pad filter.
  • 185—Install a new dehumidifier filter. Clear the monitor by touching “dismiss” after adding a new filter.
  • 187—Wash or put in a new ventilator filter. Clear the screen by hitting “dismiss” after adding a fresh filter.
  • 188/189—Get a new UV bulb. Ring Donelson Air Service Experts at 615-953-9885 for help.
  • 210—Register online for outdoor temperature. Download the Lyric app to finish 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 correct thermostat operation.
  • 399—No Internet. Verify 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. Get the Lyric app and follow the steps to link your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump needs service. Contact Donelson Air Service Experts at 615-953-9885 for support.
  • 168—Wi-Fi radio error. Contact Donelson Air Service Experts at 615-953-9885 for help.
  • 170—Internal memory error. Call Donelson Air Service Experts at 615-953-9885 for support.
  • 171—Set date and time. Finish these settings so scheduling can work.
  • 173—Thermostat temperature sensor error. Contact Donelson Air Service Experts at 615-953-9885 for help.
  • 175—AC power reconnected. No action necessary.
  • 177—Indoor temperature sensor error. Contact Donelson Air Service Experts at 615-953-9885 for support.
  • 178—Outdoor temperature sensor error. Contact Donelson Air Service Experts at 615-953-9885 for support.
  • 181/182—Get a new air filter. Clear the screen by tapping “dismiss” after putting in a new filter.
  • 183—Clean humidifier tank and add a new water filter. Clear the display by tapping “dismiss” after finishing these steps.
  • 184—Get a new humidifier pad. Clear the thermostat by tapping “dismiss” after adding a new pad filter.
  • 185—Get a new dehumidifier filter. Clear the thermostat by touching “dismiss” after adding a fresh filter.
  • 186—Wash ventilator core. Clear the monitor by touching “dismiss” after completing this task.
  • 187—Clean or replace ventilator filter. Clear the display by touching “dismiss” after getting a new filter.
  • 188/189—Install a new UV bulb. Reach Donelson Air Service Experts at 615-953-9885 for support.
  • 210—Register online for outdoor temperature. Get the Lyric app to complete this step and ensure accurate thermostat operation.
  • 388—Register online for remote access and outdoor 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 choose new Wi-Fi network.
  • 508—Wi-Fi not set up. Use the Lyric app and follow the procedures to connect your thermostat.

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

Our Experts are Available to Provide Support

If you’re still having problems after going through the troubleshooting steps, our Experts are available to assist you. Call us at 615-953-9885 and we’ll be out as fast as we can to figure out the malfunction.

If you use an aging thermostat, right now is a fantastic time to think over a replacement. Thermostat technology has advanced in recent years Ask us for more information on how smart thermostats can make your residence better while helping save on utility bills throughout the year.

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