How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the top thermostat producers, and we proudly install them on a usual basis in Toronto. They’re sturdy and reliable. Plus, Honeywell is regularly enhancing its technology, resulting in more features for your residence.

Still, all thermostats can run into issues from time to time. That’s why we’ve prepared this informative guidebook to walk you through troubleshooting.

While you can typically repair the majority of thermostat troubles alone, they sometimes need Expert help. Our HVAC Experts are ready to assist you when you need us. We’re only a call away at 289-201-2346.

Let’s get started with the process by figuring out what type of thermostat your residence 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 type, but it’s also the least efficient for lowering energy expenses.
  • Programmable—This thermostat features a digital screen and arrows you touch to determine your desired temperature. You can also use daily programs to reduce the temperature when you’re away and set it higher when you come home.
  • Smart—You won’t have to schedule any programs on this thermostat, since it learns your day. It instinctively changes the temperature when you or loved ones are gone to help you save on heating and cooling costs. You can also raise or lower 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 several malfunctions that may occur. The majority of of these problems don’t require professional support and are uncomplicated enough to solve by yourself.

Common Honeywell Thermostat Problems

Each thermostat has a special kind of codes that correspond to the malfunctions that take place.

Think how easy it can be to repair a computer by restarting it. In many instances, diagnosing a thermostat can be just as uncomplicated.

Here are some of the most encountered Honeywell thermostat issues. These include the following programmable thermostats:

Display is Blank

If the display is clear on your programmable thermostat, you may need to get new batteries. If that doesn’t solve the issue or you rely on a smart thermostat, there may be a wiring issue.

Next, you should check the power is enabled for your furnace or air handler. Verify the switch close to the indoor system is switched “up”.

Also, you should confirm all furnace cabinet or air handler doors/panels are securely fastened.

A panel that isn’t tight may trip the safety switch, which stops power to the equipment.

While it’s less common, a blank screen might signify you should replace your thermostat.

Heating and Cooling System Won’t Turn On

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

During warm weather, verify you put the thermostat below the ambient temperature. When it’s cold, make sure it’s higher. This sounds goofy, but we’ve seen it happen lots of times.

Ensure the power switch by your indoor equipment is in the “on” position. You should also make sure the cabinet doors or panels are tight on your furnace cabinet or air handler. An unsecured panel can trip the safety switch, diverting electricity to the equipment.

Heating or cooling still won’t run? Confirm circuit breakers haven’t flipped and that your HVAC unit isn’t showing error codes.

“Cool On” or “Heat On” is Flashing

First, confirm your thermostat is switched to “cool” or “heat.”

Then, verify it’s calling for the appropriate unit to turn on. This is usually indicated by “cool on,” “heat on” or an icon.

If this phrase or the icon is blinking, your thermostat is in a five-minute delay state. This mode keeps your system from harmful short cycling. This could 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 Commercial HVAC at 289-201-2346 for help.
  • 168—Wi-Fi radio error. Reach Lyric technical support at 800-633-3991. 170—Internal memory error. Call 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 restarted. No action required.
  • 181/182—Replace air filter. Clear the monitor by touching “dismiss” after putting in a new filter.
  • 184—Install a new humidifier pad. Clear the display by tapping “dismiss” after installing a clean pad filter.
  • 185—Replace dehumidifier filter. Clear the thermostat by hitting “dismiss” after installing a new filter.
  • 187—Wash or install a new ventilator filter. Clear the screen by tapping “dismiss” after adding a fresh filter.
  • 188/189—Get a new UV bulb. Contact Service Experts Commercial HVAC at 289-201-2346 for assistance.
  • 210—Register online for outdoor temperature. Download the Lyric app to complete 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 correct 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 set up. Get the Lyric app and follow the procedure to link your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump requires service. Contact Service Experts Commercial HVAC at 289-201-2346 for help.
  • 168—Wi-Fi radio error. Contact Service Experts Commercial HVAC at 289-201-2346 for support.
  • 170—Internal memory error. Reach Service Experts Commercial HVAC at 289-201-2346 for support.
  • 171—Set date and time. Finalize these settings so scheduling can run.
  • 173—Thermostat temperature sensor error. Call Service Experts Commercial HVAC at 289-201-2346 for support.
  • 175—AC power restored. No action needed.
  • 177—Indoor temperature sensor error. Call Service Experts Commercial HVAC at 289-201-2346 for help.
  • 178—Outdoor temperature sensor error. Reach Service Experts Commercial HVAC at 289-201-2346 for help.
  • 181/182—Install a new air filter. Clear the monitor by hitting “dismiss” after putting in a new filter.
  • 183—Wash humidifier tank and add a new water filter. Clear the screen by tapping “dismiss” after completing these tasks.
  • 184—Install a new humidifier pad. Clear the display by touching “dismiss” after installing pad filter.
  • 185—Get a new dehumidifier filter. Clear the thermostat by hitting “dismiss” after installing a new filter.
  • 186—Clean ventilator core. Clear the monitor by hitting “dismiss” after completing this task.
  • 187—Clean or get a new ventilator filter. Clear the screen by tapping “dismiss” after buying a new filter.
  • 188/189—Replace UV bulb. Reach Service Experts Commercial HVAC at 289-201-2346 for help.
  • 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 outside temperature. Download the Lyric app to complete 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 choose new Wi-Fi network.
  • 508—Wi-Fi not connected. Download the Lyric app and follow the process to connect your thermostat.

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

Our Experts are Available to Provide Assistance

If you’re still having issues after going through the troubleshooting steps, our pros are here to support you. Give us a call at 289-201-2346 and we’ll be out as fast as we can to determine the malfunction.

If you use a dated thermostat, right now is a good time to consider a new thermostat. Thermostat technology has gotten better over the last few years. Ask us for more info on how smart thermostats can make your residence better while helping save on energy bills all year.

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