How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the best thermostat manufacturers, and we proudly install them on a regular basis in Nashville. They’re durable and reliable. Also, Honeywell is regularly updating its technology, resulting in more features for your household.

Still, every thermostat can run into problems now and then. Due to this, we’ve prepared this valuable manual to walk you through troubleshooting.

While you can usually solve the majority of thermostat problems by yourself, they sometimes call for Expert assistance. Our home comfort Experts are available to assist you when you need us. We’re merely a call away at 615-953-9885.

Let’s begin the process by determining what model of thermostat your residence 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 kind, but it’s also the least efficient for reducing energy expenses.
  • Programmable—This thermostat features a digital screen and arrows you use to set your desired temperature. You can also use daily programs to reduce the temperature when you’re away and increase it when you return.
  • Smart—You won’t have to make any programs on this thermostat, because it learns your day. It instinctively raises and lowers the temperature when you or loved ones are gone to help you save on utility bills. You can also change the temperature anywhere on your phone or other Wi-Fi-enabled device. 

As is the case with most technologically advanced solutions, there are regular glitches that might happen. Many of these troubles don’t require professional help and are easy to repair by yourself.

Common Honeywell Thermostat Problems

Every thermostat has an exclusive set of codes that correspond to the problems that occur.

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

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

Display is Blank

If the display is empty on your programmable thermostat, you could need to put in new batteries. If that doesn’t fix the issue or you use a smart thermostat, there could be a wiring malfunction.

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

In addition to that, you should make certain all furnace cabinet or air handler doors/panels are sturdily fastened.

A loose panel may trigger the safety switch, which cuts off power to the equipment.

While it’s less common, an empty screen might indicate you should get a new thermostat.

Heating and Cooling System Won’t Turn On

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

When it’s hot, make sure you set the thermostat lower than the room temperature. When it’s cool, verify it’s higher. This sounds silly, but we’ve seen it take place a lot of times.

Ensure the power switch by 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 open panel can activate the safety switch, cutting off current to the equipment.

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

“Cool On” or “Heat On” is Blinking

To begin, check your thermostat is on “cool” or “heat.”

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

If this set of words or the picture is pulsing, your thermostat is in a five-minute delay state. This setting protects your system from harmful short cycling. This may take place if you lose power.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump needs service. Call Donelson Air Service Experts at 615-953-9885 for support.
  • 168—Wi-Fi radio error. Contact Lyric technical support at 800-633-3991. 170—Internal memory error. Call Lyric technical support at 800-633-3991.
  • 171—Set date and time. Finalize these settings so scheduling can occur.
  • 173—Thermostat temperature sensor error. Reach Lyric technical support at 800-633-3991.
  • 175—AC power restarted. No action required.
  • 181/182—Replace air filter. Clear the display by touching “dismiss” after installing a new filter.
  • 184—Install a new humidifier pad. Clear the display by tapping “dismiss” after installing a fresh pad filter.
  • 185—Install a new dehumidifier filter. Clear the monitor by touching “dismiss” after putting in a new filter.
  • 187—Rinse or install a new ventilator filter. Clear the screen by tapping “dismiss” after adding a fresh filter.
  • 188/189—Install a new UV bulb. Call Donelson Air Service Experts at 615-953-9885 for help.
  • 210—Register online for outdoor temperature. Download the Lyric app to do this step and ensure correct thermostat operation.
  • 388—Register online for remote access and exterior temperature. Get the Lyric app to do 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 choose new Wi-Fi network.
  • 508—Wi-Fi not set. Use the Lyric app and follow the steps to link your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump needs service. Contact Donelson Air Service Experts at 615-953-9885 for support.
  • 168—Wi-Fi radio error. Reach Donelson Air Service Experts at 615-953-9885 for support.
  • 170—Internal memory error. Call Donelson Air Service Experts at 615-953-9885 for support.
  • 171—Set date and time. Finish these settings so scheduling can operate.
  • 173—Thermostat temperature sensor error. Reach Donelson Air Service Experts at 615-953-9885 for help.
  • 175—AC power restored. No action needed.
  • 177—Indoor temperature sensor error. Reach Donelson Air Service Experts at 615-953-9885 for help.
  • 178—Outdoor temperature sensor error. Contact Donelson Air Service Experts at 615-953-9885 for help.
  • 181/182—Get a new air filter. Clear the monitor by tapping “dismiss” after putting in a new filter.
  • 183—Clean humidifier tank and install a new water filter. Clear the display by hitting “dismiss” after doing these procedures.
  • 184—Install a new humidifier pad. Clear the thermostat by tapping “dismiss” after adding a new pad filter.
  • 185—Install a new dehumidifier filter. Clear the screen by touching “dismiss” after putting in a fresh filter.
  • 186—Wash ventilator core. Clear the monitor by touching “dismiss” after finishing this task.
  • 187—Clean or replace ventilator filter. Clear the monitor by touching “dismiss” after getting a new filter.
  • 188/189—Install a new UV bulb. Reach Donelson Air Service Experts at 615-953-9885 for support.
  • 210—Register online for outdoor temperature. Get the Lyric app to complete this step and ensure accurate thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Get the Lyric app to finish this step and ensure accurate thermostat operation.
  • 399—No Internet. Confirm 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. Get the Lyric app and follow the process to connect your thermostat.

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

Our Experts are Available to Provide Assistance

If you’re still having problems after going through the troubleshooting steps, our Experts are ready to support you. Call us at 615-953-9885 and we’ll be out rapidly to determine the malfunction.

If you rely on a dated thermostat, right now is a great time to think about a replacement. Thermostat technology has advanced lately Ask us for more information on how smart thermostats can make your residence better while helping save on energy bills throughout the year.

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