How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the best thermostat producers, and we proudly install them on a frequent basis in Columbus. They’re durable and reliable. In addition, Honeywell is constantly advancing its technology, offering more features for your home.

Still, every thermostat can run into troubles once in awhile. Due to this, we’ve prepared this helpful guidebook to walk you through troubleshooting. While Honeywell thermostat problems are rare, they do occur. 

While you can typically solve the majority of thermostat issues alone, they occasionally need Expert assistance. Our heating and cooling pros are here to assist you when you need us. We’re merely a call away at 614-334-3192.

Let’s begin the process by determining what kind of thermostat your house has.

What Kind of Thermostat Do I Have?

There are three types of thermostats:

  • Manual—This is the older dial-shaped thermostat. You won’t experience error codes with this kind, but it’s also the least efficient for reducing energy bills.
  • Programmable—This thermostat includes a digital screen and arrows you press to choose your desired temperature. You can also choose daily programs to lower the temperature when you’re at work and raise it when you come home.
  • Smart—You won’t have to set any programs on this thermostat, as it adjusts to your schedule. It instinctively adjusts the temperature when you or family members are gone 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 the majority of technologically advanced products, there are several malfunctions that may happen. Most of these situations don’t need Expert help and are easy to solve by yourself.

Common Honeywell Thermostat Problems

Each thermostat has a special set of codes assigned to the glitches that occur.

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

Here is a listing the most reported Honeywell thermostat problems. These are applicable to the following programmable thermostats:

Display is Blank

If the display is clear on your programmable thermostat, you may need to put in new batteries. If that doesn’t solve the problem or you use a smart thermostat, there might be a wiring problem.

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

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

A loose panel may trip the safety switch, which cuts off power to the unit.

While it’s less common, an empty monitor might signify you need to get a new thermostat.

HVAC System Won’t Run

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

In the summer, confirm you put the thermostat beneath the current temperature. In the winter, make sure it’s higher. This sounds goofy, but we’ve seen it happen 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 secure on your furnace cabinet or air handler. A loose panel can trip the safety switch, cutting off current to the equipment.

System still won’t start? Verify circuit breakers haven’t turned off and that your HVAC unit isn’t displaying error codes.

“Cool On” or “Heat On” is Flashing

First, ensure your thermostat is switched to “cool” or “heat.”

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

If these words or the icon is pulsing, your thermostat is in a five-minute delay state. This feature stops your unit from damaging short cycling. This may take place if you lose electricity.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump needs service. Call Service Experts Heating & Air Conditioning at 614-334-3192 for help.
  • 168—Wi-Fi radio error. Call 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 necessary.
  • 181/182—Put in a new air filter. Clear the display by hitting “dismiss” after putting in a clean filter.
  • 184—Install a new humidifier pad. Clear the screen by touching “dismiss” after adding a new pad filter.
  • 185—Put in a new dehumidifier filter. Clear the thermostat by touching “dismiss” after adding a clean filter.
  • 187—Wash or install a new ventilator filter. Clear the monitor by touching “dismiss” after adding a fresh filter.
  • 188/189—Get a new UV bulb. Call Service Experts Heating & Air Conditioning at 614-334-3192 for support.
  • 210—Register online for outdoor temperature. Get 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 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 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, see this thermostat’s user manual.

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump must be serviced service. Contact Service Experts Heating & Air Conditioning at 614-334-3192 for assistance.
  • 168—Wi-Fi radio error. Call Service Experts Heating & Air Conditioning at 614-334-3192 for support.
  • 170—Internal memory error. Reach Service Experts Heating & Air Conditioning at 614-334-3192 for help.
  • 171—Set date and time. Complete these settings so scheduling can work.
  • 173—Thermostat temperature sensor error. Call Service Experts Heating & Air Conditioning at 614-334-3192 for assistance.
  • 175—AC power reconnected. No action necessary.
  • 177—Indoor temperature sensor error. Call Service Experts Heating & Air Conditioning at 614-334-3192 for assistance.
  • 178—Outdoor temperature sensor error. Reach Service Experts Heating & Air Conditioning at 614-334-3192 for assistance.
  • 181/182—Get a new air filter. Clear the thermostat by touching “dismiss” after installing a clean filter.
  • 183—Rinse humidifier tank and install a new water filter. Clear the monitor by tapping “dismiss” after finishing these steps.
  • 184—Get a new humidifier pad. Clear the screen by tapping “dismiss” after installing pad filter.
  • 185—Install a new dehumidifier filter. Clear the screen by touching “dismiss” after installing a new filter.
  • 186—Wash ventilator core. Clear the display by tapping “dismiss” after doing this task.
  • 187—Clean or replace ventilator filter. Clear the screen by tapping “dismiss” after getting a new filter.
  • 188/189—Install a new UV bulb. Reach Service Experts Heating & Air Conditioning at 614-334-3192 for support.
  • 210—Register online for exterior temperature. Download the Lyric app to do this step and ensure proper thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Get 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 set up. Get the Lyric app and follow the steps to connect your thermostat.

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

Our Experts are Here to Provide Assistance

If you’re still experiencing problems after trying the troubleshooting steps, our Experts are available to assist you. Reach us at 614-334-3192 and we’ll be out as fast as we can to figure out the malfunction.

If you have an aging thermostat, now is a good time to think over a replacement. Thermostat technology has gotten better lately Ask us for more details on how smart thermostats can make your home better while helping save on energy bills all year.

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