How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the leading thermostat brands, and we proudly install them on a regular basis in Grand Island. They’re durable and reliable. In addition, Honeywell is constantly improving its technology, resulting in more features for your home.

Nevertheless, all thermostats can have issues once in awhile. That’s why we’ve compiled this helpful handbook to walk you through troubleshooting.

While you can usually repair the majority of thermostat issues on your own, they occasionally call for Expert help. Our heating and cooling Experts are ready to assist you when you need us. We’re merely a call away at 308-210-4398.

Let’s get started with the process by determining what type of thermostat your residence has.

What Type of Thermostat Do I Have?

There are three models of thermostats:

  • Manual—This is the older dial-shaped thermostat. You won’t experience error codes with this kind, but it’s also the least efficient for saving on utility expenses.
  • Programmable—This thermostat features a digital screen and arrows you use to set your desired temperature. You can also use daily programs to reduce the temperature when you’re away and set it higher when you return.
  • Smart—You won’t have to make any programs on this thermostat, as it adjusts to your routine. It instinctively adjusts the temperature when you or loved ones are gone to help you save on heating and cooling costs. You can also change the temperature anywhere using your phone or other Wi-Fi-enabled device. 

As is the case with many technologically advanced products, there are several malfunctions that can happen. Many of these problems don’t call for pro support and are uncomplicated enough to fix alone.

Common Honeywell Thermostat Troubles

Each thermostat has a special set of codes that correspond to the malfunctions that occur.

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

Here is a guide to the most encountered Honeywell thermostat problems. These involve the following programmable thermostats:

Display is Blank

If the monitor is blank on your programmable thermostat, you may need to put in new batteries. If that doesn’t take care of the issue or you use a smart thermostat, there could be a wiring problem.

Next, you should check the power is flowing for your furnace or air handler. Confirm the switch by the indoor system is switched “up”.

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

An unsecured panel may trigger the safety switch, which cuts off power to the unit.

Less frequently, a blank monitor could signify you need to get a new thermostat.

Heating and Cooling Equipment Won’t Run

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

During warm weather, confirm you set the thermostat lower than the ambient temperature. In the winter, confirm it’s higher. This sounds goofy, but we’ve seen it happen a lot of times.

Make sure the power switch by your indoor system is in the “on” position. You should also check the cabinet doors or panels are closed on your furnace cabinet or air handler. An open panel can activate the safety switch, diverting current to the unit.

Heating or cooling still won’t run? Verify circuit breakers haven’t turned off and that your HVAC unit isn’t experiencing error codes.

“Cool On” or “Heat On” is Blinking

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

Then, ensure it’s signaling the appropriate equipment to turn on. This is usually shown by “cool on,” “heat on” or an icon.

If these words or the picture is blinking, your thermostat is in a five-minute delay status. This setting protects your unit from bad short cycling. This can occur if you lose power.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump requires service. Call McElroy Service Experts at 308-210-4398 for help.
  • 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. Complete these settings so scheduling can occur.
  • 173—Thermostat temperature sensor error. Reach Lyric technical support at 800-633-3991.
  • 175—AC power restored. No action needed.
  • 181/182—Install a new air filter. Clear the monitor by touching “dismiss” after adding a clean filter.
  • 184—Install a new humidifier pad. Clear the screen by touching “dismiss” after putting in a clean pad filter.
  • 185—Install a new dehumidifier filter. Clear the monitor by tapping “dismiss” after adding a fresh filter.
  • 187—Clean or install a new ventilator filter. Clear the monitor by tapping “dismiss” after installing a new filter.
  • 188/189—Replace UV bulb. Call McElroy Service Experts at 308-210-4398 for assistance.
  • 210—Register online for outside temperature. Get the Lyric app to finish this step and ensure proper thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Get the Lyric app to finish 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. Use the Lyric app and follow the procedure to configure your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump requires service. Call McElroy Service Experts at 308-210-4398 for support.
  • 168—Wi-Fi radio error. Reach McElroy Service Experts at 308-210-4398 for assistance.
  • 170—Internal memory error. Call McElroy Service Experts at 308-210-4398 for assistance.
  • 171—Set date and time. Finalize these settings so scheduling can work.
  • 173—Thermostat temperature sensor error. Contact McElroy Service Experts at 308-210-4398 for help.
  • 175—AC power reconnected. No action required.
  • 177—Indoor temperature sensor error. Call McElroy Service Experts at 308-210-4398 for assistance.
  • 178—Outdoor temperature sensor error. Call McElroy Service Experts at 308-210-4398 for support.
  • 181/182—Install a new air filter. Clear the display by touching “dismiss” after installing a new filter.
  • 183—Wash humidifier tank and replace water filter. Clear the thermostat by tapping “dismiss” after completing these procedures.
  • 184—Get a new humidifier pad. Clear the screen by tapping “dismiss” after installing pad filter.
  • 185—Replace dehumidifier filter. Clear the display by touching “dismiss” after adding a new filter.
  • 186—Clean ventilator core. Clear the thermostat by touching “dismiss” after completing this task.
  • 187—Wash or get a new ventilator filter. Clear the screen by tapping “dismiss” after installing a new filter.
  • 188/189—Add a new UV bulb. Get in touch with McElroy Service Experts at 308-210-4398 for assistance.
  • 210—Register online for outdoor 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 correct 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 configured. Download the Lyric app and follow the procedures to connect your thermostat.

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

Our Experts are Ready to Provide Assistance

If you’re still having issues after trying the troubleshooting process, our pros are here to assist you. Call us at 308-210-4398 and we’ll come to your house quickly to figure out the malfunction.

If you have an aging thermostat, right now is a fantastic time to think about a new thermostat. Thermostat technology has advanced in recent years Ask us for more details on how smart thermostats can make your house more convenient while helping save on heating and cooling bills all year.

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