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How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the best thermostat brands, and we proudly install them on a frequent basis in Oakville. They’re durable and trustworthy. In addition, Honeywell is constantly improving its technology, resulting in more features for your family.

Nevertheless, all thermostats can experience problems every now and then. As a result, we’ve put together this useful guide to run through troubleshooting. While Honeywell thermostat problems are rare, they do pop up. 

While you can often repair many thermostat troubles by yourself, they sometimes call for Expert assistance. Our HVAC pros are ready to assist you when you need us. We’re only a call away at 289-813-5566.

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

What Model 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 one, but it’s also the least efficient for reducing energy bills.
  • Programmable—This thermostat includes a digital screen and arrows you press to determine your desired temperature. You can also use daily programs to reduce the temperature when you’re gone and set it higher when you come home.
  • Smart—You won’t have to make any programs on this thermostat, as it adjusts to your day. It intuitively raises and lowers the temperature when you or loved ones are gone to help you save on energy costs. You can also raise or lower the temperature anywhere on your phone or other Wi-Fi-enabled device. 

As is the case with most technologically advanced things, there are regular glitches that can take place. The majority of of these situations don’t need Expert help and are uncomplicated enough to repair alone.

Common Honeywell Thermostat Troubles

Each thermostat has an exclusive group of codes that correspond to the problems that happen.

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

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

Display is Blank

If the display is empty on your programmable thermostat, you could need to put in new batteries. If that doesn’t solve the issue or you have a smart thermostat, there may be a wiring issue.

Next, you should ensure the power is on for your furnace or air handler. Confirm the switch close to the indoor unit is in the “on” position.

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

A loose panel may trigger the safety switch, which cuts off power to the equipment.

Infrequently, a clear screen may indicate you need to install a new thermostat.

Comfort Equipment Won’t Turn On

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

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

Ensure the power switch near your indoor equipment is in the “on” position. You should also make sure the cabinet doors or panels are secure on your furnace cabinet or air handler. An open panel can trigger the safety switch, stopping power to the equipment.

System 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

First, make sure your thermostat is set to “cool” or “heat.”

Then, verify it’s calling for the correct equipment to start. This is typically shown by “cool on,” “heat on” or an icon.

If this set of words or the illustration is pulsing, your thermostat is in a five-minute delay state. This setting protects your unit from bad 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 requires service. Call Abbey Air Service Experts at 289-813-5566 for assistance.
  • 168—Wi-Fi radio error. Contact Lyric technical support at 800-633-3991. 170—Internal memory error. Call Lyric technical support at 800-633-3991.
  • 171—Set date and time. Complete 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 required.
  • 181/182—Put in a new air filter. Clear the monitor by tapping “dismiss” after installing a clean filter.
  • 184—Put in a new humidifier pad. Clear the thermostat by hitting “dismiss” after installing a fresh pad filter.
  • 185—Replace dehumidifier filter. Clear the display by touching “dismiss” after installing a fresh filter.
  • 187—Clean or install a new ventilator filter. Clear the screen by touching “dismiss” after adding a clean filter.
  • 188/189—Get a new UV bulb. Call Abbey Air Service Experts at 289-813-5566 for support.
  • 210—Register online for outdoor temperature. Get the Lyric app to finish this step and ensure proper thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Use the Lyric app to finish this step and ensure accurate 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 configured. Use the Lyric app and follow the process to link your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump must be serviced service. Reach Abbey Air Service Experts at 289-813-5566 for support.
  • 168—Wi-Fi radio error. Contact Abbey Air Service Experts at 289-813-5566 for help.
  • 170—Internal memory error. Contact Abbey Air Service Experts at 289-813-5566 for support.
  • 171—Set date and time. Complete these settings so scheduling can run.
  • 173—Thermostat temperature sensor error. Contact Abbey Air Service Experts at 289-813-5566 for support.
  • 175—AC power reconnected. No action required.
  • 177—Indoor temperature sensor error. Contact Abbey Air Service Experts at 289-813-5566 for support.
  • 178—Outdoor temperature sensor error. Contact Abbey Air Service Experts at 289-813-5566 for assistance.
  • 181/182—Get a new air filter. Clear the display by touching “dismiss” after adding a fresh filter.
  • 183—Clean humidifier tank and add a new water filter. Clear the thermostat by touching “dismiss” after finishing these tasks.
  • 184—Replace humidifier pad. Clear the thermostat by touching “dismiss” after getting a new pad filter.
  • 185—Get a new dehumidifier filter. Clear the screen by hitting “dismiss” after putting in a new filter.
  • 186—Wash ventilator core. Clear the thermostat by touching “dismiss” after finishing this task.
  • 187—Clean or get a new ventilator filter. Clear the display by tapping “dismiss” after installing a new filter.
  • 188/189—Get a new UV bulb. Contact Abbey Air Service Experts at 289-813-5566 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. Download the Lyric app to finish this step and ensure proper thermostat operation.
  • 399—No Internet. Confirm 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 up. Get the Lyric app and follow the process to connect your thermostat.

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

Our Experts are Here to Provide Assistance

If you’re still experiencing problems after going through the troubleshooting steps, our pros are ready to help. Call us at 289-813-5566 and we’ll arrive rapidly to diagnose the malfunction.

If you rely on an aging thermostat, now is a good time to consider a new device. Thermostat technology has advanced over the last few years. Ask us for more information on how smart thermostats can make your house more convenient while helping save on utility bills all year.

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