How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the best thermostat brands, and we proudly install them on a frequent basis in Memphis. They’re durable and dependable. In addition, Honeywell is regularly improving its technology, offering more features for your house.

Nevertheless, all thermostats can experience issues now and then. That’s why we’ve compiled this helpful guidebook to walk you through troubleshooting.

While you can often repair most thermostat issues by yourself, they occasionally need Expert support. Our home comfort pros are available to assist you when you need us. We’re only a call away at 901-235-1196.

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

What Model 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 heating and cooling bills.
  • Programmable—This thermostat has a digital screen and arrows you use to determine your desired temperature. You can also choose daily programs to reduce the temperature when you’re away and set it higher when you get back.
  • Smart—You won’t have to set any programs on this thermostat, since it learns your schedule. It intuitively raises and lowers the temperature when you or other household members are out and about 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 many technologically advanced solutions, there are several malfunctions that might happen. Most of these issues don’t need Expert support and are simple to fix by yourself.

Common Honeywell Thermostat Troubles

Each thermostat has a special kind of codes assigned to the problems that take place.

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

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

Display is Blank

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

Next, you should make sure the power is flowing for your furnace or air handler. Confirm the switch close to the indoor unit is switched “up”.

Additionally, you should confirm all furnace cabinet or air handler doors/panels are securely secured.

A loose panel may trip the safety switch, which stops power to the equipment.

Infrequently, an empty screen might indicate you need to replace your thermostat.

Heating and Cooling Unit Won’t Work

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

During warm weather, verify you put the thermostat lower than the ambient temperature. In the winter, make sure it’s higher. This sounds absurd, but we’ve seen it take place a lot of times.

Ensure the power switch near your indoor equipment is in the “on” position. You should also check 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 equipment.

System still won’t start? Make sure circuit breakers haven’t turned off and that your HVAC equipment isn’t experiencing error codes.

“Cool On” or “Heat On” is Blinking

To start, verify your thermostat is set to “cool” or “heat.”

Then, verify it’s calling for the correct unit to run. This is often indicated by “cool on,” “heat on” or an icon.

If this set of words or the picture is flashing, your thermostat is in a five-minute delay status. This feature keeps your system from damaging short cycling. This could occur if your power is interrupted.

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 901-235-1196 for assistance.
  • 168—Wi-Fi radio error. Reach Lyric technical support at 800-633-3991. 170—Internal memory error. Reach Lyric technical support at 800-633-3991.
  • 171—Set date and time. Finish these settings so scheduling can take place.
  • 173—Thermostat temperature sensor error. Reach Lyric technical support at 800-633-3991.
  • 175—AC power restored. No action necessary.
  • 181/182—Replace air filter. Clear the display by hitting “dismiss” after putting in a new filter.
  • 184—Replace humidifier pad. Clear the thermostat by touching “dismiss” after adding a new pad filter.
  • 185—Put in a new dehumidifier filter. Clear the screen by hitting “dismiss” after installing a new filter.
  • 187—Rinse or put in a new ventilator filter. Clear the thermostat by tapping “dismiss” after putting in a clean filter.
  • 188/189—Install a new UV bulb. Ring Service Experts Heating & Air Conditioning at 901-235-1196 for assistance.
  • 210—Register online for outdoor temperature. Use the Lyric app to complete 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 accurate 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. Get the Lyric app and follow the process to link your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump requires service. Call Service Experts Heating & Air Conditioning at 901-235-1196 for help.
  • 168—Wi-Fi radio error. Call Service Experts Heating & Air Conditioning at 901-235-1196 for support.
  • 170—Internal memory error. Contact Service Experts Heating & Air Conditioning at 901-235-1196 for assistance.
  • 171—Set date and time. Complete these settings so scheduling can operate.
  • 173—Thermostat temperature sensor error. Reach Service Experts Heating & Air Conditioning at 901-235-1196 for support.
  • 175—AC power restored. No action required.
  • 177—Indoor temperature sensor error. Call Service Experts Heating & Air Conditioning at 901-235-1196 for support.
  • 178—Outdoor temperature sensor error. Call Service Experts Heating & Air Conditioning at 901-235-1196 for help.
  • 181/182—Install a new air filter. Clear the screen by touching “dismiss” after adding a clean filter.
  • 183—Clean humidifier tank and add a new water filter. Clear the thermostat by touching “dismiss” after finishing these procedures.
  • 184—Replace humidifier pad. Clear the display by touching “dismiss” after adding a new pad filter.
  • 185—Install a new dehumidifier filter. Clear the screen by touching “dismiss” after adding a clean filter.
  • 186—Wash ventilator core. Clear the screen by touching “dismiss” after doing this task.
  • 187—Rinse or get a new ventilator filter. Clear the display by touching “dismiss” after installing a new filter.
  • 188/189—Install a new UV bulb. Contact Service Experts Heating & Air Conditioning at 901-235-1196 for assistance.
  • 210—Register online for outside temperature. Get the Lyric app to finish 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 accurate 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 process to connect your thermostat.

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

Our Experts are Ready to Provide Assistance

If you’re still running into troubles after going through the troubleshooting process, our Experts are here to help. Reach us at 901-235-1196 and we’ll be out as fast as we can to determine the issue.

If you rely on an older thermostat, now is a fantastic time to consider a replacement. Thermostat technology has come a long way lately Ask us for more information on how smart thermostats can make your home more comfortable while helping save on utility expenses year-round.

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