How to Troubleshoot Honeywell Thermostat Errors

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

Still, each thermostat can run into problems at one time or another. As a result, we’ve compiled this informative manual to walk you through troubleshooting. While Honeywell thermostat problems are rare, they do occur. 

While you can usually repair most thermostat issues on your own, they sometimes need Expert help. Our heating and cooling professionals are here to help when you need us. We’re merely a call away at 613-817-1591.

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

What Type of Thermostat Do I Have?

There are three types of thermostats:

  • Manual—This is the classic dial-shaped thermostat. You won’t experience error codes with this one, but it’s also the least efficient for reducing energy bills.
  • Programmable—This thermostat features a digital screen and arrows you press to determine your desired temperature. You can also set daily programs to decrease the temperature when you’re gone and raise it when you return.
  • Smart—You won’t have to set any programs on this thermostat, since it learns your day. It automatically adjusts the temperature when you or other household members are out and about to help you save on energy bills. You can also change the temperature anywhere using your phone or other Wi-Fi-enabled device. 

As you’re aware many technologically advanced things, there are common glitches that may occur. The majority of of these issues don’t require pro assistance and are uncomplicated enough to fix on your own.

Common Honeywell Thermostat Problems

Every thermostat has a special kind of codes assigned to the troubles that occur.

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

Here is a listing the most encountered Honeywell thermostat issues. These involve the following programmable thermostats:

Display is Blank

If the screen is blank on your programmable thermostat, you might need to install new batteries. If that doesn’t fix the problem or you rely on a smart thermostat, there might be a wiring malfunction.

Next, you should check the power is enabled for your furnace or air handler. Make sure the switch close to the indoor equipment is in the “on” position.

In addition to that, you should confirm all furnace cabinet or air handler doors/panels are tightly fastened.

A panel that isn’t tight may activate the safety switch, which cuts off power to the system.

While it’s less common, a blank monitor might indicate you need to replace your thermostat.

HVAC Unit Won’t Turn On

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

During warm weather, confirm you schedule the thermostat beneath the room temperature. When it’s cool, make sure 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 comfirm the cabinet doors or panels are tight on your furnace cabinet or air handler. An unsecured panel can trigger the safety switch, cutting off power to the system.

Equipment still won’t turn on? Confirm circuit breakers haven’t tripped and that your HVAC unit isn’t displaying error codes.

“Cool On” or “Heat On” is Flickering

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

Then, verify it’s telling the right equipment to turn on. This is typically indicated by “cool on,” “heat on” or a picture.

If these words or the icon is blinking, your thermostat is in a five-minute delay status. This mode keeps your system from bad short cycling. This can take place if you lose power.

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 613-817-1591 for help.
  • 168—Wi-Fi radio error. Contact Lyric technical support at 800-633-3991. 170—Internal memory error. Reach Lyric technical support at 800-633-3991.
  • 171—Set date and time. Complete these settings so scheduling can occur.
  • 173—Thermostat temperature sensor error. Call Lyric technical support at 800-633-3991.
  • 175—AC power restored. No action required.
  • 181/182—Install a new air filter. Clear the display by tapping “dismiss” after installing a fresh filter.
  • 184—Replace humidifier pad. Clear the thermostat by touching “dismiss” after putting in a fresh pad filter.
  • 185—Put in a new dehumidifier filter. Clear the thermostat by tapping “dismiss” after putting in a clean filter.
  • 187—Rinse or put in a new ventilator filter. Clear the thermostat by tapping “dismiss” after adding a clean filter.
  • 188/189—Get a new UV bulb. Ring Service Experts Heating & Air Conditioning at 613-817-1591 for support.
  • 210—Register online for exterior temperature. Get the Lyric app to finish this step and ensure correct thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Use 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 choose new Wi-Fi network.
  • 508—Wi-Fi not set. Download the Lyric app and follow the steps to configure your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump needs service. Reach Service Experts Heating & Air Conditioning at 613-817-1591 for assistance.
  • 168—Wi-Fi radio error. Call Service Experts Heating & Air Conditioning at 613-817-1591 for support.
  • 170—Internal memory error. Call Service Experts Heating & Air Conditioning at 613-817-1591 for help.
  • 171—Set date and time. Finalize these settings so scheduling can operate.
  • 173—Thermostat temperature sensor error. Contact Service Experts Heating & Air Conditioning at 613-817-1591 for assistance.
  • 175—AC power reconnected. No action needed.
  • 177—Indoor temperature sensor error. Reach Service Experts Heating & Air Conditioning at 613-817-1591 for help.
  • 178—Outdoor temperature sensor error. Reach Service Experts Heating & Air Conditioning at 613-817-1591 for assistance.
  • 181/182—Get a new air filter. Clear the thermostat by tapping “dismiss” after putting in a fresh filter.
  • 183—Rinse humidifier tank and replace water filter. Clear the monitor by touching “dismiss” after finishing these procedures.
  • 184—Get a new humidifier pad. Clear the monitor by tapping “dismiss” after installing pad filter.
  • 185—Install a new dehumidifier filter. Clear the display by tapping “dismiss” after installing a clean filter.
  • 186—Wash ventilator core. Clear the thermostat by touching “dismiss” after completing this task.
  • 187—Wash or get a new ventilator filter. Clear the screen by hitting “dismiss” after buying a new filter.
  • 188/189—Install a new UV bulb. Get in touch with Service Experts Heating & Air Conditioning at 613-817-1591 for assistance.
  • 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 outdoor temperature. Download 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. Use the Lyric app and follow the procedures to connect your thermostat.

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

Our Experts are Ready to Help

If you’re still experiencing issues after trying the troubleshooting process, our Experts are here to assist you. Call us at 613-817-1591 and we’ll be out as fast as we can to determine the issue.

If you rely on an aging thermostat, now is a great time to consider a new thermostat. Thermostat technology has come a long way over the last few years. Ask us for more info on how smart thermostats can make your house more convenient while helping save on energy bills throughout the year.

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