How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the leading thermostat manufacturers, and we proudly install them on a usual basis in Voorhees. They’re long-lasting and reliable. In addition, Honeywell is frequently improving its technology, bringing more features for your family.

Nevertheless, all thermostats can experience troubles every now and then. As a result, we’ve compiled this helpful handbook to walk you through troubleshooting.

While you can typically solve most thermostat problems alone, they occasionally call for Expert support. Our home comfort professionals are available to support you when you need us. We’re just a call away at 856-310-4824.

Let’s start the process by figuring out what model of thermostat your house has.

What Model of Thermostat Do I Have?

There are three models of thermostats:

  • Manual—This is the classic dial-shaped thermostat. You won’t experience error codes with this type, but it’s also the least efficient for reducing heating and cooling bills.
  • Programmable—This thermostat features a digital screen and arrows you press to determine your desired temperature. You can also use daily programs to decrease the temperature when you’re away and raise it when you come home.
  • Smart—You won’t have to set any programs on this thermostat, because it learns your routine. It intuitively raises and lowers the temperature when you or family members are away to help you save on energy expenses. You can also raise or lower the temperature anywhere using your phone or other Wi-Fi-enabled device. 

As is the case with many technologically advanced things, there are regular malfunctions that can take place. Many of these troubles don’t call for professional assistance and are simple to solve on your own.

Common Honeywell Thermostat Problems

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

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

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

Display is Blank

If the screen is blank on your programmable thermostat, you might need to get new batteries. If that doesn’t take care of the trouble or you use a smart thermostat, there could be a wiring problem.

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

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

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

Infrequently, a blank monitor might signify you will need to get a new thermostat.

Heating and Cooling Equipment Won’t Start

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

When it’s hot, make sure you set the thermostat beneath the room temperature. When it’s cool, make sure it’s higher. This sounds goofy, but we’ve seen it occur a lot of times.

Make sure the power switch near your indoor system is in the “on” position. You should also make sure the cabinet doors or panels are secure on your furnace cabinet or air handler. A loose panel can activate the safety switch, cutting off current to the unit.

Heating or cooling still won’t turn on? Make sure circuit breakers haven’t flipped and that your HVAC system isn’t experiencing error codes.

“Cool On” or “Heat On” is Blinking

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

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

If this set of words or the picture is pulsing, your thermostat is in a five-minute delay state. This mode protects your system from bad short cycling. This may occur if you lose electricity.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump must be serviced. Call Atmostemp Service Experts at 856-310-4824 for help.
  • 168—Wi-Fi radio error. Contact Lyric technical support at 800-633-3991. 170—Internal memory error. Contact 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. Reach Lyric technical support at 800-633-3991.
  • 175—AC power restarted. No action needed.
  • 181/182—Put in a new air filter. Clear the display by touching “dismiss” after putting in a clean filter.
  • 184—Replace humidifier pad. Clear the display by hitting “dismiss” after adding a clean pad filter.
  • 185—Replace dehumidifier filter. Clear the screen by touching “dismiss” after putting in a clean filter.
  • 187—Wash or put in a new ventilator filter. Clear the monitor by touching “dismiss” after installing a fresh filter.
  • 188/189—Replace UV bulb. Contact Atmostemp Service Experts at 856-310-4824 for help.
  • 210—Register online for exterior temperature. Get the Lyric app to do this step and ensure accurate thermostat operation.
  • 388—Register online for remote access and exterior temperature. Use 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 choose new Wi-Fi network.
  • 508—Wi-Fi not set up. Get the Lyric app and follow the procedure to link your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump needs service. Contact Atmostemp Service Experts at 856-310-4824 for assistance.
  • 168—Wi-Fi radio error. Contact Atmostemp Service Experts at 856-310-4824 for help.
  • 170—Internal memory error. Contact Atmostemp Service Experts at 856-310-4824 for support.
  • 171—Set date and time. Finalize these settings so scheduling can run.
  • 173—Thermostat temperature sensor error. Contact Atmostemp Service Experts at 856-310-4824 for assistance.
  • 175—AC power restored. No action needed.
  • 177—Indoor temperature sensor error. Call Atmostemp Service Experts at 856-310-4824 for help.
  • 178—Outdoor temperature sensor error. Call Atmostemp Service Experts at 856-310-4824 for assistance.
  • 181/182—Replace air filter. Clear the display by hitting “dismiss” after adding a fresh filter.
  • 183—Wash humidifier tank and add a new water filter. Clear the screen by touching “dismiss” after finishing these tasks.
  • 184—Get a new humidifier pad. Clear the screen by tapping “dismiss” after adding a new pad filter.
  • 185—Replace dehumidifier filter. Clear the thermostat by hitting “dismiss” after installing a clean filter.
  • 186—Wash ventilator core. Clear the screen by hitting “dismiss” after doing this task.
  • 187—Clean or install a new ventilator filter. Clear the display by touching “dismiss” after buying a new filter.
  • 188/189—Replace UV bulb. Get in touch with Atmostemp Service Experts at 856-310-4824 for support.
  • 210—Register online for outdoor temperature. Use the Lyric app to do this step and ensure accurate thermostat operation.
  • 388—Register online for remote access and exterior temperature. Use the Lyric app to complete 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 select new Wi-Fi network.
  • 508—Wi-Fi not configured. Download the Lyric app and follow the process to connect your thermostat.

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

Our Experts are Ready to Provide Support

If you’re still running into issues after working through the troubleshooting list, our Experts are ready to support you. Reach us at 856-310-4824 and we’ll come to your house rapidly to diagnose the malfunction.

If you have an aging thermostat, now is a great time to think over a new thermostat. Thermostat technology has advanced in recent years Ask us for more info on how smart thermostats can make your residence more convenient while helping save on utility expenses all year.

Contact Us