How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the best thermostat brands, and we proudly install them on a regular basis in Albany. They’re sturdy and reliable. Plus, Honeywell is frequently advancing its technology, offering more features for your home.

Still, all thermostats can run into troubles every so often. That’s why we’ve compiled this valuable handbook to run through troubleshooting.

While you can usually repair most thermostat problems alone, they occasionally require Expert support. Our home comfort professionals are here to assist you when you need us. We’re merely a call away at 518-417-2938.

Let’s start the process by determining what kind of thermostat your residence has.

What Kind 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 one, but it’s also the least efficient for reducing energy bills.
  • Programmable—This thermostat includes a digital screen and arrows you touch to choose your desired temperature. You can also use daily programs to reduce the temperature when you’re away and set it higher when you return.
  • Smart—You won’t have to make any programs on this thermostat, since it learns your routine. It automatically adjusts the temperature when you or loved ones are away to help you save on utility bills. You can also change the temperature anywhere using your phone or other Wi-Fi-enabled device. 

As is the case with many technologically advanced solutions, there are common malfunctions that may occur. The majority of of these troubles don’t need pro assistance and are simple to fix by yourself.

Common Honeywell Thermostat Problems

Every thermostat has a special kind of codes that correspond to the problems that happen.

Think how uncomplicated it can be to fix a computer by restarting it. For the most part, diagnosing a thermostat can be just as uncomplicated.

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

Display is Blank

If the monitor is blank on your programmable thermostat, you could need to replace the batteries. If that doesn’t take care of the trouble or you have a smart thermostat, there could be a wiring issue.

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

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

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

Less frequently, a blank display might mean you need to install a new thermostat.

Comfort Equipment Won’t Run

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

When it’s hot, confirm you put the thermostat below the current temperature. When it’s cool, make sure it’s higher. This sounds absurd, but we’ve seen it happen many times.

Confirm the power switch by your indoor system 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 open panel can trip the safety switch, stopping power to the system.

Heating or cooling still won’t turn on? Confirm circuit breakers haven’t flipped and that your HVAC equipment isn’t displaying error codes.

“Cool On” or “Heat On” is Flashing

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

Then, check it’s signaling the right system to turn on. This is usually shown by “cool on,” “heat on” or a picture.

If these words or the illustration is blinking, your thermostat is in a five-minute delay mode. This mode stops your system from damaging short cycling. This could take place if you lose power.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump needs service. Call Roland J. Down Service Experts at 518-417-2938 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. Complete these settings so scheduling can take place.
  • 173—Thermostat temperature sensor error. Contact Lyric technical support at 800-633-3991.
  • 175—AC power restored. No action needed.
  • 181/182—Put in a new air filter. Clear the thermostat by hitting “dismiss” after putting in a clean filter.
  • 184—Replace humidifier pad. Clear the monitor by touching “dismiss” after adding a fresh pad filter.
  • 185—Replace dehumidifier filter. Clear the monitor by hitting “dismiss” after putting in a fresh filter.
  • 187—Wash or install a new ventilator filter. Clear the screen by tapping “dismiss” after putting in a fresh filter.
  • 188/189—Replace UV bulb. Ring Roland J. Down Service Experts at 518-417-2938 for help.
  • 210—Register online for exterior temperature. Use the Lyric app to finish this step and ensure correct thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Get the Lyric app to finish this step and ensure proper 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. Download the Lyric app and follow the procedure to link your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump requires service. Reach Roland J. Down Service Experts at 518-417-2938 for assistance.
  • 168—Wi-Fi radio error. Reach Roland J. Down Service Experts at 518-417-2938 for help.
  • 170—Internal memory error. Contact Roland J. Down Service Experts at 518-417-2938 for assistance.
  • 171—Set date and time. Complete these settings so scheduling can work.
  • 173—Thermostat temperature sensor error. Reach Roland J. Down Service Experts at 518-417-2938 for assistance.
  • 175—AC power reconnected. No action necessary.
  • 177—Indoor temperature sensor error. Contact Roland J. Down Service Experts at 518-417-2938 for support.
  • 178—Outdoor temperature sensor error. Reach Roland J. Down Service Experts at 518-417-2938 for assistance.
  • 181/182—Install a new air filter. Clear the monitor by hitting “dismiss” after putting in a new filter.
  • 183—Wash humidifier tank and replace water filter. Clear the screen by tapping “dismiss” after completing these tasks.
  • 184—Replace humidifier pad. Clear the thermostat by hitting “dismiss” after adding a new pad filter.
  • 185—Get a new dehumidifier filter. Clear the thermostat by hitting “dismiss” after adding a fresh filter.
  • 186—Wash ventilator core. Clear the screen by touching “dismiss” after doing this task.
  • 187—Rinse or install a new ventilator filter. Clear the monitor by touching “dismiss” after installing a new filter.
  • 188/189—Install a new UV bulb. Reach Roland J. Down Service Experts at 518-417-2938 for help.
  • 210—Register online for exterior temperature. Download the Lyric app to finish this step and ensure accurate thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Get the Lyric app to complete this step and ensure proper 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 connected. Download the Lyric app and follow the procedures to connect your thermostat.

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

Our Experts are Here to Provide Support

If you’re still experiencing problems after working through the troubleshooting steps, our professionals are here to support you. Call us at 518-417-2938 and we’ll be out as fast as we can to figure out the malfunction.

If you use an older thermostat, now is a fantastic time to think about a new device. Thermostat technology has advanced over the last few years. Ask us for more info on how smart thermostats can make your residence better while helping save on heating and cooling bills year-round.

Contact Us