How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the top thermostat brands, and we proudly install them on a usual basis in Kitchener. They’re sturdy and reliable. Plus, Honeywell is constantly updating its technology, resulting in more features for your family.

Still, every thermostat can have issues every now and then. That’s why we’ve compiled this informative handbook to run through troubleshooting.

While you can typically repair many thermostat problems alone, they occasionally need Expert help. Our HVAC Experts are ready to support you when you need us. We’re just a call away at 519-804-1617.

Let’s get started with the process by determining what model of thermostat your home has.

What Model of Thermostat Do I Have?

There are three kinds 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 lowering heating and cooling expenses.
  • Programmable—This thermostat includes a digital screen and arrows you use to determine your desired temperature. You can also set daily programs to reduce the temperature when you’re away and raise it when you return.
  • Smart—You won’t have to schedule any programs on this thermostat, as it learns your routine. It intuitively adjusts the temperature when you or family members 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 most technologically advanced solutions, there are common malfunctions that can take place. Most of these issues don’t call for professional assistance and are simple to solve alone.

Common Honeywell Thermostat Problems

Every thermostat has an exclusive group of codes that correspond to the malfunctions that happen.

Think how simple it can be to fix a computer by restarting it. In many instances, correcting a thermostat can be just as easy.

Here are some of the most common Honeywell thermostat problems. These include the following programmable thermostats:

Display is Blank

If the screen is empty on your programmable thermostat, you may need to install new batteries. If that doesn’t solve the problem or you use a smart thermostat, there may be a wiring problem.

Next, you should ensure the power is flowing for your furnace or air handler. Make sure the switch near the indoor equipment is in the “on” position.

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

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

While it’s less common, a blank screen might indicate you need to install a new thermostat.

Heating and Cooling System Won’t Turn On

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

During warm weather, confirm you schedule the thermostat beneath the room temperature. When it’s cool, confirm it’s higher. This sounds goofy, but we’ve seen it happen many times.

Ensure the power switch by 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. An unsecured panel can trip the safety switch, cutting off electricity to the equipment.

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

“Cool On” or “Heat On” is Flickering

To start, confirm your thermostat is on “cool” or “heat.”

Then, make sure it’s calling for the correct system to turn on. This is usually demonstrated by “cool on,” “heat on” or an illustration.

If these words or the illustration is blinking, your thermostat is in a five-minute delay mode. This mode keeps your equipment from damaging 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 Boehmers/Cronin Emery Service Experts at 519-804-1617 for assistance.
  • 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. Finalize these settings so scheduling can run.
  • 173—Thermostat temperature sensor error. Contact Lyric technical support at 800-633-3991.
  • 175—AC power restarted. No action necessary.
  • 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—Replace dehumidifier filter. Clear the monitor by hitting “dismiss” after putting in a clean filter.
  • 187—Rinse or replace ventilator filter. Clear the monitor by hitting “dismiss” after putting in a fresh filter.
  • 188/189—Install a new UV bulb. Contact Boehmers/Cronin Emery Service Experts at 519-804-1617 for assistance.
  • 210—Register online for outdoor temperature. Download the Lyric app to complete this step and ensure correct thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Download the Lyric app to complete 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. Get the Lyric app and follow the procedure to connect your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump needs service. Call Boehmers/Cronin Emery Service Experts at 519-804-1617 for help.
  • 168—Wi-Fi radio error. Contact Boehmers/Cronin Emery Service Experts at 519-804-1617 for support.
  • 170—Internal memory error. Contact Boehmers/Cronin Emery Service Experts at 519-804-1617 for help.
  • 171—Set date and time. Finalize these settings so scheduling can work.
  • 173—Thermostat temperature sensor error. Call Boehmers/Cronin Emery Service Experts at 519-804-1617 for help.
  • 175—AC power restored. No action needed.
  • 177—Indoor temperature sensor error. Reach Boehmers/Cronin Emery Service Experts at 519-804-1617 for help.
  • 178—Outdoor temperature sensor error. Call Boehmers/Cronin Emery Service Experts at 519-804-1617 for support.
  • 181/182—Get a new air filter. Clear the display by tapping “dismiss” after putting in a clean filter.
  • 183—Wash humidifier tank and replace water filter. Clear the screen by hitting “dismiss” after doing these procedures.
  • 184—Get a new humidifier pad. Clear the thermostat by touching “dismiss” after getting a new pad filter.
  • 185—Install a new dehumidifier filter. Clear the display by tapping “dismiss” after adding a fresh filter.
  • 186—Wash ventilator core. Clear the screen by tapping “dismiss” after finishing this task.
  • 187—Rinse or replace ventilator filter. Clear the monitor by tapping “dismiss” after buying a new filter.
  • 188/189—Add a new UV bulb. Reach Boehmers/Cronin Emery Service Experts at 519-804-1617 for assistance.
  • 210—Register online for outside temperature. Download the Lyric app to complete this step and ensure correct thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Get the Lyric app to do 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 configured. Download the Lyric app and follow the procedures to connect your thermostat.

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

Our Experts are Here to Provide Assistance

If you’re still experiencing troubles after trying the troubleshooting process, our Experts are ready to assist you. Reach us at 519-804-1617 and we’ll arrive rapidly to diagnose the problem.

If you use a dated thermostat, now is a good time to think over a new device. Thermostat technology has gotten better in recent years Ask us for more info on how smart thermostats can make your house comfier while helping save on energy bills year-round.

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