How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the best thermostat brands, and we proudly install them on a usual basis in Rochester. They’re sturdy and reliable. In addition, Honeywell is constantly improving its technology, bringing more features for your home.

Nevertheless, all thermostats can run into problems at times. Due to this, we’ve prepared this useful guidebook to run through troubleshooting.

While you can usually solve most thermostat problems on your own, they occasionally call for Expert assistance. Our heating and cooling professionals are available to assist you when you need us. We’re just a call away at 603-923-4570.

Let’s get started with the process by determining what kind of thermostat your home 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 experience error codes with this kind, but it’s also the least efficient for lowering energy expenses.
  • Programmable—This thermostat has a digital screen and arrows you press to set your desired temperature. You can also set daily programs to decrease the temperature when you’re gone and raise it when you come home.
  • Smart—You won’t have to schedule any programs on this thermostat, since it adjusts to your day. It instinctively raises and lowers the temperature when you or other household members are away to help you save on utility expenses. You can also adjust the temperature anywhere using your phone or other Wi-Fi-enabled device. 

As you know many technologically advanced things, there are several glitches that might happen. The majority of of these situations don’t need professional support and are simple to fix alone.

Common Honeywell Thermostat Troubles

Each thermostat has a special kind of codes assigned to the malfunctions that occur.

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

Here is a listing the most encountered 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 replace the batteries. If that doesn’t fix the problem or you have a smart thermostat, there might be a wiring malfunction.

Next, you should make sure the power is flowing for your furnace or air handler. Make sure the switch by the indoor equipment is in the “on” position.

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

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

Less frequently, a blank display can indicate you need to replace your thermostat.

Heating and Cooling Equipment Won’t Work

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

During warm weather, confirm 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 many times.

Confirm the power switch close to 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, diverting power to the system.

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

“Cool On” or “Heat On” is Blinking

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

Then, make sure it’s telling the right unit to start. This is usually shown by “cool on,” “heat on” or an icon.

If these words or the picture is flashing, your thermostat is in a five-minute delay status. This setting keeps your unit from bad short cycling. This can happen if you lose electricity.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump needs service. Call Strogen's Service Experts at 603-923-4570 for support.
  • 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 take place.
  • 173—Thermostat temperature sensor error. Reach Lyric technical support at 800-633-3991.
  • 175—AC power restarted. No action required.
  • 181/182—Replace air filter. Clear the display by hitting “dismiss” after adding a clean filter.
  • 184—Install a new humidifier pad. Clear the monitor by hitting “dismiss” after adding a new pad filter.
  • 185—Put in a new dehumidifier filter. Clear the monitor by tapping “dismiss” after installing a fresh filter.
  • 187—Clean or install a new ventilator filter. Clear the display by tapping “dismiss” after putting in a fresh filter.
  • 188/189—Replace UV bulb. Ring Strogen's Service Experts at 603-923-4570 for support.
  • 210—Register online for exterior temperature. Get the Lyric app to complete this step and ensure proper 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. Verify 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. Download the Lyric app and follow the process to configure your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump requires service. Reach Strogen's Service Experts at 603-923-4570 for support.
  • 168—Wi-Fi radio error. Call Strogen's Service Experts at 603-923-4570 for help.
  • 170—Internal memory error. Call Strogen's Service Experts at 603-923-4570 for help.
  • 171—Set date and time. Finalize these settings so scheduling can work.
  • 173—Thermostat temperature sensor error. Reach Strogen's Service Experts at 603-923-4570 for assistance.
  • 175—AC power resumed. No action needed.
  • 177—Indoor temperature sensor error. Contact Strogen's Service Experts at 603-923-4570 for assistance.
  • 178—Outdoor temperature sensor error. Call Strogen's Service Experts at 603-923-4570 for support.
  • 181/182—Replace air filter. Clear the display by touching “dismiss” after installing a fresh filter.
  • 183—Wash humidifier tank and install a new water filter. Clear the screen by hitting “dismiss” after doing these procedures.
  • 184—Install a new humidifier pad. Clear the screen by touching “dismiss” after getting a new pad filter.
  • 185—Replace dehumidifier filter. Clear the display by touching “dismiss” after installing a clean filter.
  • 186—Clean ventilator core. Clear the display by touching “dismiss” after doing this task.
  • 187—Clean or get a new ventilator filter. Clear the monitor by touching “dismiss” after buying a new filter.
  • 188/189—Add a new UV bulb. Contact Strogen's Service Experts at 603-923-4570 for support.
  • 210—Register online for outside temperature. Download the Lyric app to finish this step and ensure proper 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. Check 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. Download the Lyric app and follow the process to connect your thermostat.

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

Our Experts are Available to Provide Assistance

If you’re still experiencing issues after going through the troubleshooting process, our Experts are here to support you. Reach us at 603-923-4570 and we’ll arrive quickly to determine the problem.

If you rely on an aging thermostat, right now is a fantastic time to think about a new device. Thermostat technology has gotten better in recent years Ask us for more information on how smart thermostats can make your home comfier while helping save on energy costs throughout the year.

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