How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the top thermostat brands, and we proudly install them on a regular basis in Cocoa. They’re sturdy and trustworthy. Plus, Honeywell is constantly enhancing its technology, resulting in more features for your house.

However, every thermostat can experience troubles once in awhile. Due to this, we’ve put together this helpful handbook to run through troubleshooting.

While you can usually solve most thermostat troubles on your own, they often require Expert assistance. Our heating and cooling professionals are available to help when you need us. We’re just a call away at 321-428-7635.

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

What Kind of Thermostat Do I Have?

There are three kinds of thermostats:

  • Manual—This is the classic dial-shaped thermostat. You won’t run into error codes with this one, but it’s also the least efficient for lowering energy bills.
  • Programmable—This thermostat includes a digital screen and arrows you use to determine your desired temperature. You can also choose daily programs to reduce the temperature when you’re away 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 instinctively raises and lowers the temperature when you or loved ones are away to help you save on heating and cooling expenses. You can also change the temperature anywhere via your phone or other Wi-Fi-enabled device. 

As is the case with the majority of technologically advanced things, there are regular glitches that might occur. The majority of of these issues don’t require Expert assistance and are simple to solve on your own.

Common Honeywell Thermostat Problems

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

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

Here is a guide to the most reported Honeywell thermostat issues. These apply to the following programmable thermostats:

Display is Blank

If the display is clear on your programmable thermostat, you might need to install new batteries. If that doesn’t take care of the malfunction or you use a smart thermostat, there might be a wiring problem.

Next, you should check the power is enabled for your furnace or air handler. Confirm the switch near the indoor unit is in the “on” position.

Also, you should make certain all furnace cabinet or air handler doors/panels are tightly in place.

A panel that isn’t tight may trigger the safety switch, which disconnects power to the unit.

Less frequently, a clear display can signify you should get a new thermostat.

Comfort Equipment Won’t Work

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

In the summer, verify you set the thermostat below the room temperature. When it’s cool, make sure it’s higher. This sounds goofy, but we’ve seen it take place many times.

Ensure the power switch close to 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 unsecured panel can trigger the safety switch, cutting off electricity to the system.

Unit still won’t run? Make sure circuit breakers haven’t tripped and that your HVAC equipment isn’t showing error codes.

“Cool On” or “Heat On” is Flickering

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

Then, verify it’s calling for the right system to run. This is often shown by “cool on,” “heat on” or an illustration.

If these words or the icon is pulsing, your thermostat is in a five-minute delay mode. This setting stops your equipment 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 requires service. Call Service Experts Heating & Air Conditioning at 321-428-7635 for help.
  • 168—Wi-Fi radio error. Call 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. Call Lyric technical support at 800-633-3991.
  • 175—AC power resumed. No action needed.
  • 181/182—Install a new air filter. Clear the monitor by hitting “dismiss” after putting in a clean filter.
  • 184—Put in a new humidifier pad. Clear the display by touching “dismiss” after installing a fresh pad filter.
  • 185—Install a new dehumidifier filter. Clear the monitor by tapping “dismiss” after adding a new filter.
  • 187—Clean or replace ventilator filter. Clear the monitor by hitting “dismiss” after putting in a fresh filter.
  • 188/189—Get a new UV bulb. Contact Service Experts Heating & Air Conditioning at 321-428-7635 for support.
  • 210—Register online for outside temperature. Use 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 do this step and ensure correct thermostat operation.
  • 399—No Internet. Confirm 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 procedure to configure your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump must be serviced service. Contact Service Experts Heating & Air Conditioning at 321-428-7635 for support.
  • 168—Wi-Fi radio error. Contact Service Experts Heating & Air Conditioning at 321-428-7635 for assistance.
  • 170—Internal memory error. Contact Service Experts Heating & Air Conditioning at 321-428-7635 for assistance.
  • 171—Set date and time. Finish these settings so scheduling can run.
  • 173—Thermostat temperature sensor error. Call Service Experts Heating & Air Conditioning at 321-428-7635 for help.
  • 175—AC power reconnected. No action necessary.
  • 177—Indoor temperature sensor error. Call Service Experts Heating & Air Conditioning at 321-428-7635 for assistance.
  • 178—Outdoor temperature sensor error. Reach Service Experts Heating & Air Conditioning at 321-428-7635 for support.
  • 181/182—Replace air filter. Clear the display by tapping “dismiss” after installing a new filter.
  • 183—Wash humidifier tank and install a new water filter. Clear the thermostat by touching “dismiss” after completing these tasks.
  • 184—Replace humidifier pad. Clear the monitor by tapping “dismiss” after installing pad filter.
  • 185—Install a new dehumidifier filter. Clear the screen by hitting “dismiss” after installing a fresh filter.
  • 186—Clean ventilator core. Clear the display by tapping “dismiss” after completing this task.
  • 187—Wash or replace ventilator filter. Clear the screen by hitting “dismiss” after getting a new filter.
  • 188/189—Get a new UV bulb. Contact Service Experts Heating & Air Conditioning at 321-428-7635 for support.
  • 210—Register online for outside temperature. Get the Lyric app to do this step and ensure accurate thermostat operation.
  • 388—Register online for remote access and exterior temperature. Get 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 pick new Wi-Fi network.
  • 508—Wi-Fi not configured. Use the Lyric app and follow the steps to connect your thermostat.

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

Our Experts are Here to Help

If you’re still running into issues after going through the troubleshooting process, our pros are here to support you. Give us a call at 321-428-7635 and we’ll arrive quickly to determine the problem.

If you rely on an older thermostat, now is a good time to consider a replacement. Thermostat technology has advanced over the last few years. Ask us for more info on how smart thermostats can make your residence more comfortable while helping save on energy expenses year-round.

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