How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the leading thermostat producers, and we proudly install them on a frequent basis in Fort Myers. They’re durable and trustworthy. In addition, Honeywell is constantly improving its technology, offering more features for your family.

However, each thermostat can run into problems now and then. That’s why we’ve put together this valuable guide to run through troubleshooting.

While you can typically fix many thermostat issues by yourself, they often require Expert support. Our HVAC Experts are here to support you when you need us. We’re only a call away at 239-908-6991.

Let’s begin the process by finding out what model of thermostat your house 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 run into error codes with this type, but it’s also the least efficient for lowering energy bills.
  • 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 at work and set it higher when you get back.
  • Smart—You won’t have to schedule any programs on this thermostat, since it picks up on your schedule. It automatically adjusts the temperature when you or family members are out and about to help you save on energy bills. You can also change the temperature anywhere using your phone or other Wi-Fi-enabled device. 

As is the case with most technologically advanced things, there are regular problems that may take place. Most of these problems don’t require pro support and are simple to solve by yourself.

Common Honeywell Thermostat Problems

All thermostats have a unique kind of codes matching the troubles that take place.

Think how uncomplicated it can be to fix a computer by restarting it. For the most part, correcting a thermostat can be just as uncomplicated.

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

Display is Blank

If the monitor is clear on your programmable thermostat, you may need to install 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 ensure the power is enabled for your furnace or air handler. Make sure the switch close to the indoor equipment is in the “on” position.

In addition to that, you should confirm all furnace cabinet or air handler doors/panels are securely fastened.

A loose panel may activate the safety switch, which stops power to the unit.

While it’s less common, a clear screen might signify you need to get a new thermostat.

Comfort Equipment Won’t Start

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

In the summer, make sure you set the thermostat lower than the ambient temperature. In the winter, verify it’s higher. This sounds goofy, but we’ve seen it take place lots of times.

Confirm the power switch near your indoor system is in the “on” position. You should also comfirm the cabinet doors or panels are closed on your furnace cabinet or air handler. An open panel can trigger the safety switch, stopping electricity to the system.

Unit still won’t turn on? Verify circuit breakers haven’t turned off and that your HVAC system isn’t displaying error codes.

“Cool On” or “Heat On” is Flickering

To start, ensure your thermostat is set to “cool” or “heat.”

Then, check it’s telling the right system to turn on. This is often indicated by “cool on,” “heat on” or an icon.

If these words or the picture is blinking, your thermostat is in a five-minute delay mode. This mode protects your equipment from damaging 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 Service Experts Heating & Air Conditioning at 239-908-6991 for support.
  • 168—Wi-Fi radio error. Contact Lyric technical support at 800-633-3991. 170—Internal memory error. Reach Lyric technical support at 800-633-3991.
  • 171—Set date and time. Finalize these settings so scheduling can occur.
  • 173—Thermostat temperature sensor error. Contact Lyric technical support at 800-633-3991.
  • 175—AC power restored. No action necessary.
  • 181/182—Install a new air filter. Clear the display by hitting “dismiss” after adding a new filter.
  • 184—Install a new humidifier pad. Clear the thermostat by touching “dismiss” after adding a fresh pad filter.
  • 185—Install a new dehumidifier filter. Clear the display by tapping “dismiss” after putting in a fresh filter.
  • 187—Wash or put in a new ventilator filter. Clear the thermostat by touching “dismiss” after installing a clean filter.
  • 188/189—Replace UV bulb. Call Service Experts Heating & Air Conditioning at 239-908-6991 for assistance.
  • 210—Register online for exterior temperature. Download the Lyric app to finish this step and ensure correct thermostat operation.
  • 388—Register online for remote access and exterior temperature. Download the Lyric app to do this step and ensure proper 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. Use the Lyric app and follow the steps to link your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump requires service. Contact Service Experts Heating & Air Conditioning at 239-908-6991 for assistance.
  • 168—Wi-Fi radio error. Contact Service Experts Heating & Air Conditioning at 239-908-6991 for assistance.
  • 170—Internal memory error. Reach Service Experts Heating & Air Conditioning at 239-908-6991 for help.
  • 171—Set date and time. Complete these settings so scheduling can work.
  • 173—Thermostat temperature sensor error. Call Service Experts Heating & Air Conditioning at 239-908-6991 for support.
  • 175—AC power reconnected. No action necessary.
  • 177—Indoor temperature sensor error. Call Service Experts Heating & Air Conditioning at 239-908-6991 for help.
  • 178—Outdoor temperature sensor error. Contact Service Experts Heating & Air Conditioning at 239-908-6991 for support.
  • 181/182—Get a new air filter. Clear the screen by hitting “dismiss” after putting in a fresh filter.
  • 183—Clean humidifier tank and install a new water filter. Clear the monitor by hitting “dismiss” after doing these procedures.
  • 184—Install a new humidifier pad. Clear the monitor by tapping “dismiss” after adding a new pad filter.
  • 185—Get a new dehumidifier filter. Clear the display by tapping “dismiss” after adding a clean filter.
  • 186—Rinse ventilator core. Clear the thermostat by hitting “dismiss” after completing this task.
  • 187—Wash or get a new ventilator filter. Clear the monitor by touching “dismiss” after installing a new filter.
  • 188/189—Get a new UV bulb. Reach Service Experts Heating & Air Conditioning at 239-908-6991 for support.
  • 210—Register online for exterior temperature. Use the Lyric app to complete this step and ensure accurate thermostat operation.
  • 388—Register online for remote access and outside temperature. Download the Lyric app to do this step and ensure correct thermostat operation.
  • 399—No Internet. Check 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 process to connect your thermostat.

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

Our Experts are Available to Help

If you’re still having problems after trying the troubleshooting steps, our Experts are here to help. Reach us at 239-908-6991 and we’ll arrive rapidly to determine the malfunction.

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

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