How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the top thermostat brands, and we proudly install them on a usual basis in Wheeling. They’re durable and dependable. Also, Honeywell is regularly enhancing its technology, offering more features for your residence.

Nevertheless, each thermostat can have troubles occasionally. That’s why we’ve prepared this valuable guide to walk you through troubleshooting. While Honeywell thermostat problems are rare, they happen. 

While you can typically repair many thermostat problems on your own, they occasionally require Expert support. Our home comfort Experts are available to help when you need us. We’re merely a call away at 847-250-6729.

Let’s begin the process by determining what model of thermostat your home has.

What Type of Thermostat Do I Have?

There are three models of thermostats:

  • Manual—This is the typical dial-shaped thermostat. You won’t have error codes with this one, but it’s also the least efficient for reducing heating and cooling costs.
  • Programmable—This thermostat has a digital screen and arrows you touch to set your desired temperature. You can also choose daily programs to decrease the temperature when you’re at work and set it higher when you come home.
  • Smart—You won’t have to set any programs on this thermostat, as it picks up on your schedule. It intuitively raises and lowers the temperature when you or loved ones are away to help you save on utility bills. You can also raise or lower the temperature anywhere using your phone or other Wi-Fi-enabled device. 

As you’re aware many technologically advanced products, there are regular malfunctions that might occur. The majority of of these issues don’t need pro support and are simple to solve alone.

Common Honeywell Thermostat Problems

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

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

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

Display is Blank

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

Next, you should check the power is flowing for your furnace or air handler. Verify the switch close to the indoor equipment is switched “up”.

In addition to that, you should make certain all furnace cabinet or air handler doors/panels are sturdily fastened.

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

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

HVAC Unit Won’t Work

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

In the summer, make sure you set the thermostat lower than the ambient temperature. When it’s cool, make sure it’s higher. This sounds silly, but we’ve seen it occur lots of times.

Confirm the power switch near your indoor unit 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 open panel can trigger the safety switch, stopping power to the system.

System still won’t start? Make sure circuit breakers haven’t tripped and that your HVAC system isn’t displaying error codes.

“Cool On” or “Heat On” is Flickering

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

Then, ensure it’s calling for the correct system to run. This is often demonstrated by “cool on,” “heat on” or a picture.

If this set of words or the icon is blinking, your thermostat is in a five-minute delay state. This feature protects your unit from damaging short cycling. This can occur if you lose power.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump needs service. Call Comfort Masters Service Experts at 847-250-6729 for assistance.
  • 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 run.
  • 173—Thermostat temperature sensor error. Call Lyric technical support at 800-633-3991.
  • 175—AC power restarted. No action necessary.
  • 181/182—Replace air filter. Clear the display by tapping “dismiss” after installing a new filter.
  • 184—Put in a new humidifier pad. Clear the monitor by touching “dismiss” after adding a new pad filter.
  • 185—Install a new dehumidifier filter. Clear the thermostat by touching “dismiss” after adding a fresh filter.
  • 187—Clean or replace ventilator filter. Clear the thermostat by touching “dismiss” after adding a fresh filter.
  • 188/189—Get a new UV bulb. Call Comfort Masters Service Experts at 847-250-6729 for support.
  • 210—Register online for exterior temperature. Download the Lyric app to finish this step and ensure accurate thermostat operation.
  • 388—Register online for remote access and outside temperature. Get the Lyric app to do this step and ensure accurate thermostat operation.
  • 399—No Internet. Check 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 procedure to connect your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump needs service. Contact Comfort Masters Service Experts at 847-250-6729 for assistance.
  • 168—Wi-Fi radio error. Reach Comfort Masters Service Experts at 847-250-6729 for support.
  • 170—Internal memory error. Contact Comfort Masters Service Experts at 847-250-6729 for support.
  • 171—Set date and time. Finalize these settings so scheduling can work.
  • 173—Thermostat temperature sensor error. Call Comfort Masters Service Experts at 847-250-6729 for assistance.
  • 175—AC power reconnected. No action required.
  • 177—Indoor temperature sensor error. Call Comfort Masters Service Experts at 847-250-6729 for help.
  • 178—Outdoor temperature sensor error. Call Comfort Masters Service Experts at 847-250-6729 for assistance.
  • 181/182—Replace air filter. Clear the display by hitting “dismiss” after putting in a clean filter.
  • 183—Clean humidifier tank and add a new water filter. Clear the screen by tapping “dismiss” after doing these steps.
  • 184—Get a new humidifier pad. Clear the screen by hitting “dismiss” after adding a new pad filter.
  • 185—Get a new dehumidifier filter. Clear the screen by touching “dismiss” after adding a new filter.
  • 186—Wash ventilator core. Clear the display by tapping “dismiss” after completing this task.
  • 187—Rinse or install a new ventilator filter. Clear the screen by touching “dismiss” after getting a new filter.
  • 188/189—Get a new UV bulb. Get in touch with Comfort Masters Service Experts at 847-250-6729 for support.
  • 210—Register online for outdoor temperature. Download the Lyric app to finish this step and ensure accurate thermostat operation.
  • 388—Register online for remote access and exterior temperature. Use the Lyric app to complete 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 choose new Wi-Fi network.
  • 508—Wi-Fi not connected. Download the Lyric app and follow the procedures to connect your thermostat.

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

Our Experts are Ready to Provide Support

If you’re still running into problems after trying the troubleshooting steps, our professionals are here to assist you. Call us at 847-250-6729 and we’ll come to your house as fast as we can to determine the malfunction.

If you rely on an aging thermostat, today is a great time to think about a new device. Thermostat technology has advanced over the last few years. Ask us for more information on how smart thermostats can make your house more comfortable while helping save on energy bills year-round.

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