How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the leading thermostat manufacturers, and we proudly install them on a regular basis in the U.S.. They’re long-lasting and dependable. In addition, Honeywell is regularly updating its technology, offering more features for your house.

Still, every thermostat can experience problems at times. As a result, we’ve put together this useful handbook to run through troubleshooting. While Honeywell thermostat troubleshooting problems are rare, they do occur.

While you can often repair many thermostat issues alone, they occasionally call for Expert support. Our HVAC professionals are available to assist you when you need us. We’re just a call away at 866-397-3787.

Let’s begin the process by finding out what kind of thermostat your house has.

What Type of Thermostat Do I Have?

There are three kinds of thermostats:

  • Manual—This is the typical dial-shaped thermostat. You won’t experience error codes with this kind, but it’s also the least efficient for reducing energy costs.
  • Programmable—This thermostat includes a digital screen and arrows you touch to choose your desired temperature. You can also use daily programs to decrease the temperature when you’re gone and increase it when you return.
  • Smart—You won’t have to schedule any programs on this thermostat, since it adjusts to your routine. It automatically changes the temperature when you or family members are gone to help you save on heating and cooling costs. You can also change the temperature anywhere on your phone or other Wi-Fi-enabled device.

As you know many technologically advanced things, there are regular malfunctions that may happen. Most of these problems don’t call for pro help and are simple to repair alone.

Common Honeywell Thermostat Troubleshooting Issues

Every Honeywell thermostat has an exclusive group of codes matching the malfunctions that happen.

Think how simple it can be to repair a computer by restarting it. In most situations, diagnosing a thermostat can be just as easy.

Here is a listing the most encountered Honeywell thermostat problems. These are applicable to the following programmable thermostats:

Display is Blank

If the screen is clear on your programmable thermostat, you may need to install new batteries. If that doesn’t solve the trouble or you use a smart thermostat, there may be a wiring problem.

Next, you should ensure the power is enabled for your furnace or air handler. Verify the switch by the indoor equipment is switched “on”.

In addition to that, 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 equipment.

While it’s less common, an empty screen might indicate you should install a new thermostat.

Heating and Cooling Unit Won’t Start

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

When it’s hot, verify you put the thermostat below the room temperature. When it’s cold, verify it’s higher. This sounds goofy, but we’ve seen it occur a lot of times.

Confirm the power switch by your indoor equipment 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 trigger the safety switch, stopping electricity to the system.

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

“Cool On” or “Heat On” is Blinking

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

Then, check it’s telling the right equipment to turn on. This is typically shown by “cool on,” “heat on” or an illustration.

If this phrase or the picture is pulsing, your thermostat is in a five-minute delay state. This setting stops your equipment from harmful short cycling. This may occur 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 & Plumbing at 866-397-3787 for help.
  • 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. Finish 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—Put in a new air filter. Clear the display by tapping “dismiss” after adding a fresh filter.
  • 184—Install a new humidifier pad. Clear the monitor by hitting “dismiss” after adding a clean pad filter.
  • 185—Put in a new dehumidifier filter. Clear the thermostat by hitting “dismiss” after adding a fresh filter.
  • 187—Wash or install a new ventilator filter. Clear the thermostat by tapping “dismiss” after putting in a fresh filter.
  • 188/189—Install a new UV bulb. Call Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for help.
  • 210—Register online for outside temperature. Get the Lyric app to do this step and ensure correct 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. 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 link your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005)

  • 164—Heat pump requires service. Reach Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for support.
  • 168—Wi-Fi radio error. Contact Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for support.
  • 170—Internal memory error. Reach Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for help.
  • 171—Set date and time. Finish these settings so scheduling can work.
  • 173—Thermostat temperature sensor error. Contact Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for support.
  • 175—AC power restored. No action necessary.
  • 177—Indoor temperature sensor error. Reach Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for support.
  • 178—Outdoor temperature sensor error. Contact Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for help.
  • 181/182—Get a new air filter. Clear the thermostat by tapping “dismiss” after putting in a clean filter.
  • 183—Rinse humidifier tank and install a new water filter. Clear the thermostat by hitting “dismiss” after finishing these steps.
  • 184—Install a new humidifier pad. Clear the monitor by tapping “dismiss” after getting a new pad filter.
  • 185—Get a new dehumidifier filter. Clear the display by tapping “dismiss” after putting in a clean filter.
  • 186—Rinse ventilator core. Clear the thermostat by hitting “dismiss” after completing this task.
  • 187—Rinse or get a new ventilator filter. Clear the monitor by tapping “dismiss” after getting a new filter.
  • 188/189—Add a new UV bulb. Get in touch with Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for help.
  • 210—Register online for exterior temperature. Get the Lyric app to do this step and ensure correct thermostat operation.
  • 388—Register online for remote access and exterior 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 set up. Use the Lyric app and follow the process to connect your thermostat.

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

Our Experts are Ready to Provide Support

If you’re still experiencing issues after going through the troubleshooting process, our professionals are ready to assist you. Reach us at 866-397-3787 and we’ll arrive rapidly to determine the issue.

If you use an aging thermostat, today is a great time to think about a new device. Thermostat technology has advanced in recent years Ask us for more details on how smart thermostats can make your house better while helping save on energy expenses all year.