How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the top thermostat manufacturers, and we proudly install them on a frequent basis in Cleveland. They’re sturdy and reliable. Plus, Honeywell is constantly advancing its technology, resulting in more features for your household.

Still, each thermostat can run into problems at times. Due to this, we’ve compiled this valuable guide to run through troubleshooting.

While you can usually fix the majority of thermostat troubles alone, they sometimes require Expert support. Our heating and cooling Experts are ready to assist you when you need us. We’re merely a call away at 440-252-1375.

Let’s start the process by finding 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 run into error codes with this one, but it’s also the least efficient for lowering energy expenses.
  • Programmable—This thermostat has a digital screen and arrows you touch to choose your desired temperature. You can also choose daily programs to reduce the temperature when you’re gone and increase it when you get back.
  • Smart—You won’t have to schedule any programs on this thermostat, as it adjusts to your schedule. It automatically adjusts the temperature when you or loved ones are out and about to help you save on utility expenses. You can also change the temperature anywhere via your phone or other Wi-Fi-enabled device. 

As is the case with most technologically advanced things, there are regular glitches that might occur. Most of these issues don’t require Expert support and are easy to repair by yourself.

Common Honeywell Thermostat Problems

Every thermostat has an exclusive kind of codes that correspond to the glitches that occur.

Think how easy it can be to fix 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 problems. These involve the following programmable thermostats:

Display is Blank

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

Next, you should make sure the power is enabled for your furnace or air handler. Verify 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 tightly in place.

An unsecured panel may trigger the safety switch, which disconnects power to the system.

Less frequently, a clear monitor can signify you need to get a new thermostat.

HVAC Equipment Won’t Run

Ensure that your thermostat is switched to “cool” or “heat,” not “off.”

In the summer, make sure you put the thermostat below the ambient temperature. When it’s cold, verify it’s higher. This sounds goofy, but we’ve seen it take place many times.

Ensure the power switch by your indoor equipment is in the “on” position. You should also make sure the cabinet doors or panels are secure on your furnace cabinet or air handler. A loose panel can trip the safety switch, stopping power to the unit.

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

“Cool On” or “Heat On” is Blinking

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

Then, ensure it’s calling for the correct unit to run. This is typically indicated by “cool on,” “heat on” or an illustration.

If this set of words or the picture is flashing, your thermostat is in a five-minute delay state. This mode keeps your unit from bad 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 must be serviced. Call Service Experts Heating & Air Conditioning at 440-252-1375 for assistance.
  • 168—Wi-Fi radio error. Reach 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 occur.
  • 173—Thermostat temperature sensor error. Call Lyric technical support at 800-633-3991.
  • 175—AC power restarted. No action necessary.
  • 181/182—Put in a new air filter. Clear the thermostat by tapping “dismiss” after installing a fresh filter.
  • 184—Put in a new humidifier pad. Clear the thermostat by hitting “dismiss” after installing a clean pad filter.
  • 185—Put in a new dehumidifier filter. Clear the thermostat by hitting “dismiss” after adding a clean filter.
  • 187—Clean or install a new ventilator filter. Clear the monitor by touching “dismiss” after installing a fresh filter.
  • 188/189—Get a new UV bulb. Contact Service Experts Heating & Air Conditioning at 440-252-1375 for support.
  • 210—Register online for outside temperature. Use the Lyric app to complete this step and ensure accurate thermostat operation.
  • 388—Register online for remote access and outside 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 select new Wi-Fi network.
  • 508—Wi-Fi not set up. Get the Lyric app and follow the steps to connect your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump must be serviced service. Contact Service Experts Heating & Air Conditioning at 440-252-1375 for assistance.
  • 168—Wi-Fi radio error. Call Service Experts Heating & Air Conditioning at 440-252-1375 for assistance.
  • 170—Internal memory error. Reach Service Experts Heating & Air Conditioning at 440-252-1375 for support.
  • 171—Set date and time. Finalize these settings so scheduling can work.
  • 173—Thermostat temperature sensor error. Reach Service Experts Heating & Air Conditioning at 440-252-1375 for help.
  • 175—AC power reconnected. No action needed.
  • 177—Indoor temperature sensor error. Reach Service Experts Heating & Air Conditioning at 440-252-1375 for support.
  • 178—Outdoor temperature sensor error. Reach Service Experts Heating & Air Conditioning at 440-252-1375 for help.
  • 181/182—Install a new air filter. Clear the screen by hitting “dismiss” after putting in a fresh filter.
  • 183—Wash humidifier tank and install a new water filter. Clear the monitor by hitting “dismiss” after completing these procedures.
  • 184—Get a new humidifier pad. Clear the monitor by tapping “dismiss” after getting a new pad filter.
  • 185—Get a new dehumidifier filter. Clear the thermostat by hitting “dismiss” after putting in a clean 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 monitor by tapping “dismiss” after installing a new filter.
  • 188/189—Add a new UV bulb. Get in touch with Service Experts Heating & Air Conditioning at 440-252-1375 for assistance.
  • 210—Register online for outdoor temperature. Download the Lyric app to complete this step and ensure proper thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Use the Lyric app to complete this step and ensure accurate 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 set up. Get the Lyric app and follow the procedures to connect your thermostat.

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

Our Experts are Available to Provide Assistance

If you’re still having troubles after working through the troubleshooting steps, our Experts are ready to assist you. Give us a call at 440-252-1375 and we’ll be out rapidly to figure out the malfunction.

If you have an older thermostat, today is a fantastic time to think about a replacement. Thermostat technology has advanced over the last few years. Ask us for more info on how smart thermostats can make your residence more convenient while helping save on heating and cooling expenses all year.

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