How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the leading thermostat manufacturers, and we proudly install them on a frequent basis in Waldorf. They’re durable and reliable. In addition, Honeywell is frequently advancing its technology, bringing more features for your residence.

However, all thermostats can experience errors at times. As a result, we’ve put together this useful guidebook to walk you through troubleshooting.

While you can often solve the majority of thermostat problems by yourself, they often require Expert support. Our home comfort professionals are here to support you when you need us. We’re merely a call away at 301-747-3140.

Let’s start the process by determining what kind of thermostat your residence has.

What Model of Thermostat Do I Have?

There are three models of thermostats:

  • Manual—This is the classic dial-shaped thermostat. You won’t run into error codes with this kind, but it’s also the least efficient for saving on energy expenses.
  • Programmable—This thermostat features a digital screen and arrows you touch to determine your desired temperature. You can also set daily programs to decrease 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 routine. It intuitively adjusts the temperature when you or loved ones are away to help you save on energy costs. You can also raise or lower the temperature anywhere on your phone or other Wi-Fi-enabled device. 

As you’re aware many technologically advanced things, there are several problems that can occur. Many of these situations don’t call for professional help and are easy to repair on your own.

Common Honeywell Thermostat Problems

Every thermostat has a special group of codes matching the glitches that happen.

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

Here are some of the most common Honeywell thermostat problems. These involve the following programmable thermostats:

Display is Blank

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

Next, you should ensure the power is enabled for your furnace or air handler. Confirm the switch near the indoor equipment is in the “on” position.

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

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

Infrequently, a clear screen can signify you will need to buy a new thermostat.

Heating and Cooling Unit Won’t Turn On

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

In the summer, confirm you put the thermostat lower than the ambient temperature. When it’s cold, make sure it’s higher. This sounds goofy, but we’ve seen it occur a lot of times.

Confirm the power switch close to 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 current to the system.

Equipment still won’t run? Verify circuit breakers haven’t flipped and that your HVAC equipment isn’t displaying error codes.

“Cool On” or “Heat On” is Flashing

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

Then, make sure it’s calling for the appropriate equipment to run. This is typically shown by “cool on,” “heat on” or an icon.

If this set of words or the icon is pulsing, your thermostat is in a five-minute delay mode. This mode stops your unit from harmful 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 requires service. Call A-PLUS Service Experts at 301-747-3140 for support.
  • 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. Finalize these settings so scheduling can take place.
  • 173—Thermostat temperature sensor error. Reach Lyric technical support at 800-633-3991.
  • 175—AC power restored. No action required.
  • 181/182—Put in a new air filter. Clear the display by tapping “dismiss” after installing a new filter.
  • 184—Replace humidifier pad. Clear the monitor by hitting “dismiss” after adding a fresh pad filter.
  • 185—Replace dehumidifier filter. Clear the monitor by touching “dismiss” after putting in a new filter.
  • 187—Wash or replace ventilator filter. Clear the thermostat by hitting “dismiss” after adding a fresh filter.
  • 188/189—Replace UV bulb. Ring A-PLUS Service Experts at 301-747-3140 for assistance.
  • 210—Register online for exterior temperature. Download the Lyric app to do this step and ensure correct thermostat operation.
  • 388—Register online for remote access and exterior 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 choose new Wi-Fi network.
  • 508—Wi-Fi not set up. Download the Lyric app and follow the steps to connect your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump requires service. Contact A-PLUS Service Experts at 301-747-3140 for support.
  • 168—Wi-Fi radio error. Call A-PLUS Service Experts at 301-747-3140 for support.
  • 170—Internal memory error. Contact A-PLUS Service Experts at 301-747-3140 for assistance.
  • 171—Set date and time. Finish these settings so scheduling can operate.
  • 173—Thermostat temperature sensor error. Contact A-PLUS Service Experts at 301-747-3140 for support.
  • 175—AC power restored. No action necessary.
  • 177—Indoor temperature sensor error. Reach A-PLUS Service Experts at 301-747-3140 for assistance.
  • 178—Outdoor temperature sensor error. Contact A-PLUS Service Experts at 301-747-3140 for help.
  • 181/182—Replace air filter. Clear the monitor by hitting “dismiss” after installing a new filter.
  • 183—Rinse humidifier tank and replace water filter. Clear the monitor by touching “dismiss” after completing these steps.
  • 184—Get a new humidifier pad. Clear the thermostat by touching “dismiss” after getting a new pad filter.
  • 185—Install a new dehumidifier filter. Clear the thermostat by tapping “dismiss” after putting in a fresh filter.
  • 186—Rinse ventilator core. Clear the display by touching “dismiss” after completing this task.
  • 187—Wash or replace ventilator filter. Clear the display by hitting “dismiss” after getting a new filter.
  • 188/189—Replace UV bulb. Reach A-PLUS Service Experts at 301-747-3140 for assistance.
  • 210—Register online for outdoor temperature. Use the Lyric app to do this step and ensure accurate thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Use the Lyric app to finish 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 choose new Wi-Fi network.
  • 508—Wi-Fi not connected. Use the Lyric app and follow the process to connect your thermostat.

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

Our Experts are Ready to Help

If you’re still experiencing issues after trying the troubleshooting steps, our pros are available to support you. Reach us at 301-747-3140 and we’ll arrive as fast as we can to diagnose the problem.

If you have an aging thermostat, right 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 house more convenient while helping save on heating and cooling costs throughout the year.

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