How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the best thermostat manufacturers, and we proudly install them on a usual basis in Roanoke. They’re sturdy and dependable. Also, Honeywell is frequently enhancing its technology, bringing more features for your house.

Still, each thermostat can run into problems once in awhile. Due to this, we’ve put together this helpful guide to walk you through troubleshooting.

While you can typically fix the majority of thermostat issues by yourself, they often require Expert help. Our HVAC pros are available to assist you when you need us. We’re just a call away at 540-302-8645.

Let’s get started with the process by figuring out what type of thermostat your home has.

What Type of Thermostat Do I Have?

There are three kinds of thermostats:

  • Manual—This is the older dial-shaped thermostat. You won’t have error codes with this type, but it’s also the least efficient for lowering energy costs.
  • Programmable—This thermostat includes a digital screen and arrows you touch to set your desired temperature. You can also set daily programs to reduce the temperature when you’re gone and increase it when you get back.
  • Smart—You won’t have to set any programs on this thermostat, as it learns your routine. It automatically adjusts the temperature when you or family members are gone to help you save on energy bills. You can also raise or lower the temperature anywhere using your phone or other Wi-Fi-enabled device. 

As is the case with most technologically advanced products, there are several glitches that might occur. Most of these troubles don’t require pro assistance and are simple to solve alone.

Common Honeywell Thermostat Troubles

Every thermostat has a unique group of codes matching the malfunctions that happen.

Think how easy it can be to restore a computer by restarting it. In most cases, troubleshooting a thermostat can be just as simple.

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

Display is Blank

If the display is clear on your programmable thermostat, you could need to install new batteries. If that doesn’t fix 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. Confirm the switch by the indoor unit is in the “on” position.

Additionally, you should confirm all furnace cabinet or air handler doors/panels are securely in place.

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

Less frequently, a clear display can indicate you need to buy a new thermostat.

Heating and Cooling Unit Won’t Run

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

In the summer, verify you schedule the thermostat below the room temperature. In the winter, make sure it’s higher. This sounds goofy, but we’ve seen it happen lots of times.

Confirm the power switch near your indoor unit 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 activate the safety switch, cutting off power to the system.

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

“Cool On” or “Heat On” is Flashing

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

Then, ensure it’s calling for the correct equipment to run. This is typically demonstrated by “cool on,” “heat on” or an illustration.

If this phrase or the illustration is blinking, your thermostat is in a five-minute delay state. This setting keeps 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 must be serviced. Call Service Experts Heating & Air Conditioning at 540-302-8645 for assistance.
  • 168—Wi-Fi radio error. Reach 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 run.
  • 173—Thermostat temperature sensor error. Reach Lyric technical support at 800-633-3991.
  • 175—AC power restored. No action necessary.
  • 181/182—Replace air filter. Clear the screen by hitting “dismiss” after putting in a fresh filter.
  • 184—Replace humidifier pad. Clear the screen by touching “dismiss” after putting in a new pad filter.
  • 185—Put in a new dehumidifier filter. Clear the thermostat by touching “dismiss” after installing a new filter.
  • 187—Wash or replace ventilator filter. Clear the monitor by tapping “dismiss” after adding a fresh filter.
  • 188/189—Install a new UV bulb. Call Service Experts Heating & Air Conditioning at 540-302-8645 for support.
  • 210—Register online for outside temperature. Get the Lyric app to complete this step and ensure accurate thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Use the Lyric app to do 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 configured. Get the Lyric app and follow the steps to link your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump needs service. Call Service Experts Heating & Air Conditioning at 540-302-8645 for assistance.
  • 168—Wi-Fi radio error. Call Service Experts Heating & Air Conditioning at 540-302-8645 for support.
  • 170—Internal memory error. Contact Service Experts Heating & Air Conditioning at 540-302-8645 for assistance.
  • 171—Set date and time. Complete these settings so scheduling can work.
  • 173—Thermostat temperature sensor error. Call Service Experts Heating & Air Conditioning at 540-302-8645 for assistance.
  • 175—AC power restored. No action needed.
  • 177—Indoor temperature sensor error. Contact Service Experts Heating & Air Conditioning at 540-302-8645 for help.
  • 178—Outdoor temperature sensor error. Reach Service Experts Heating & Air Conditioning at 540-302-8645 for assistance.
  • 181/182—Install a new air filter. Clear the screen by touching “dismiss” after putting in a clean filter.
  • 183—Clean humidifier tank and install a new water filter. Clear the monitor by hitting “dismiss” after finishing these tasks.
  • 184—Replace humidifier pad. Clear the monitor by tapping “dismiss” after getting a new pad filter.
  • 185—Get a new dehumidifier filter. Clear the thermostat by tapping “dismiss” after adding a fresh filter.
  • 186—Clean ventilator core. Clear the thermostat by tapping “dismiss” after doing this task.
  • 187—Wash or install a new ventilator filter. Clear the monitor by hitting “dismiss” after buying a new filter.
  • 188/189—Add a new UV bulb. Reach Service Experts Heating & Air Conditioning at 540-302-8645 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. Use the Lyric app to complete 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 pick new Wi-Fi network.
  • 508—Wi-Fi not connected. Get the Lyric app and follow the procedures to connect your thermostat.

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

Our Experts are Here to Provide Assistance

If you’re still running into problems after going through the troubleshooting steps, our Experts are available to help. Reach us at 540-302-8645 and we’ll arrive rapidly to determine the malfunction.

If you have an aging thermostat, now is a good time to think about a new device. Thermostat technology has come a long way in recent years Ask us for more details on how smart thermostats can make your house comfier while helping save on energy costs year-round.

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