How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the leading thermostat brands, and we proudly install them on a regular basis in Columbia. They’re durable and dependable. In addition, Honeywell is frequently improving its technology, resulting in more features for your household.

Nevertheless, all thermostats can experience issues from time to time. As a result, we’ve compiled this valuable guidebook to run through troubleshooting.

While you can usually solve most thermostat troubles on your own, they sometimes require Expert support. Our HVAC pros are ready to assist you when you need us. We’re merely a call away at 803-399-7208.

Let’s start the process by figuring out what model of thermostat your home has.

What Type of Thermostat Do I Have?

There are three kinds of thermostats:

  • Manual—This is the classic dial-shaped thermostat. You won’t have error codes with this type, but it’s also the least efficient for reducing heating and cooling bills.
  • Programmable—This thermostat includes a digital screen and arrows you press to determine your desired temperature. You can also choose daily programs to reduce the temperature when you’re at work and raise it when you get back.
  • Smart—You won’t have to schedule any programs on this thermostat, because it picks up on your schedule. It intuitively adjusts the temperature when you or family members are gone to help you save on energy expenses. You can also raise or lower the temperature anywhere via your phone or other Wi-Fi-enabled device. 

As is the case with most technologically advanced things, there are several malfunctions that can occur. Most of these troubles don’t need professional support and are uncomplicated enough to solve alone.

Common Honeywell Thermostat Troubles

All thermostats have a special kind of codes matching the troubles that happen.

Think how easy it can be to fix a computer by restarting it. Many times, troubleshooting a thermostat can be just as simple.

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

Display is Blank

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

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

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

A panel that isn’t tight may trigger the safety switch, which stops power to the system.

Infrequently, a clear monitor could mean you should replace your thermostat.

HVAC Unit Won’t Work

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

During warm weather, verify you put the thermostat below the room temperature. In the winter, verify it’s higher. This sounds goofy, but we’ve seen it occur many times.

Make sure the power switch near 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 unsecured panel can trigger the safety switch, stopping power to the system.

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

“Cool On” or “Heat On” is Flashing

To begin, verify your thermostat is set to “cool” or “heat.”

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

If this set of words or the illustration is pulsing, your thermostat is in a five-minute delay state. This mode stops your unit from bad short cycling. This can happen if you lose electricity.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump needs service. Call Midland Air Service Experts at 803-399-7208 for support.
  • 168—Wi-Fi radio error. Contact Lyric technical support at 800-633-3991. 170—Internal memory error. Contact Lyric technical support at 800-633-3991.
  • 171—Set date and time. Finish these settings so scheduling can take place.
  • 173—Thermostat temperature sensor error. Reach Lyric technical support at 800-633-3991.
  • 175—AC power restarted. No action necessary.
  • 181/182—Replace air filter. Clear the display by hitting “dismiss” after installing a new filter.
  • 184—Put in a new humidifier pad. Clear the display by touching “dismiss” after adding a new pad filter.
  • 185—Put in a new dehumidifier filter. Clear the thermostat by touching “dismiss” after installing a new filter.
  • 187—Wash or install a new ventilator filter. Clear the screen by hitting “dismiss” after putting in a new filter.
  • 188/189—Replace UV bulb. Call Midland Air Service Experts at 803-399-7208 for assistance.
  • 210—Register online for outside temperature. Get the Lyric app to do this step and ensure correct thermostat operation.
  • 388—Register online for remote access and exterior temperature. Download the Lyric app to finish this step and ensure correct 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 set up. Download the Lyric app and follow the process to link your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump requires service. Contact Midland Air Service Experts at 803-399-7208 for assistance.
  • 168—Wi-Fi radio error. Reach Midland Air Service Experts at 803-399-7208 for assistance.
  • 170—Internal memory error. Call Midland Air Service Experts at 803-399-7208 for assistance.
  • 171—Set date and time. Finish these settings so scheduling can work.
  • 173—Thermostat temperature sensor error. Contact Midland Air Service Experts at 803-399-7208 for assistance.
  • 175—AC power restored. No action necessary.
  • 177—Indoor temperature sensor error. Call Midland Air Service Experts at 803-399-7208 for assistance.
  • 178—Outdoor temperature sensor error. Contact Midland Air Service Experts at 803-399-7208 for assistance.
  • 181/182—Install a new air filter. Clear the display by touching “dismiss” after installing a fresh filter.
  • 183—Rinse humidifier tank and add a new water filter. Clear the display by touching “dismiss” after finishing these procedures.
  • 184—Replace humidifier pad. Clear the thermostat by touching “dismiss” after getting a new pad filter.
  • 185—Replace dehumidifier filter. Clear the thermostat by hitting “dismiss” after installing a clean filter.
  • 186—Rinse ventilator core. Clear the monitor by hitting “dismiss” after doing this task.
  • 187—Wash or get a new ventilator filter. Clear the screen by touching “dismiss” after buying a new filter.
  • 188/189—Get a new UV bulb. Contact Midland Air Service Experts at 803-399-7208 for assistance.
  • 210—Register online for outside temperature. Use the Lyric app to do this step and ensure proper thermostat operation.
  • 388—Register online for remote access and exterior temperature. Use 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 pick new Wi-Fi network.
  • 508—Wi-Fi not configured. Download the Lyric app and follow the process to connect your thermostat.

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

Our Experts are Ready to Help

If you’re still experiencing troubles after trying the troubleshooting steps, our professionals are ready to support you. Reach us at 803-399-7208 and we’ll arrive as fast as we can to diagnose the problem.

If you rely on an older thermostat, now is a fantastic time to think over a new thermostat. Thermostat technology has come a long way lately Ask us for more info on how smart thermostats can make your house more comfortable while helping save on energy costs all year.

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