How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the best thermostat producers, and we proudly install them on a regular basis in Columbus. They’re durable and dependable. Plus, Honeywell is constantly enhancing its technology, offering more features for your family.

Still, each thermostat can experience troubles at one time or another. As a result, we’ve prepared this informative guidebook to walk you through troubleshooting.

While you can typically repair the majority of thermostat troubles alone, they often need Expert assistance. Our heating and cooling pros are available to support you when you need us. We’re just a call away at 614-334-3192.

Let’s begin the process by determining what kind of thermostat your residence 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 have error codes with this type, but it’s also the least efficient for reducing utility bills.
  • Programmable—This thermostat features a digital screen and arrows you press to choose your desired temperature. You can also use 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 loved ones are out and about to help you save on energy costs. You can also raise or lower the temperature anywhere on your phone or other Wi-Fi-enabled device. 

As is the case with many technologically advanced products, there are regular glitches that might happen. Most of these situations don’t call for pro 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 simple it can be to fix a computer by restarting it. For the most part, diagnosing a thermostat can be just as uncomplicated.

Here is a guide to the most encountered Honeywell thermostat issues. 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 fix the issue or you rely on 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 close to the indoor equipment is switched “on”.

In addition to that, 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, a clear monitor might indicate you need to get a new thermostat.

HVAC System Won’t Run

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

In the summer, confirm you put the thermostat below the current temperature. In the winter, make sure it’s higher. This sounds absurd, but we’ve seen it happen a lot of times.

Confirm the power switch close to your indoor system 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? Confirm circuit breakers haven’t turned off and that your HVAC equipment isn’t displaying error codes.

“Cool On” or “Heat On” is Flashing

First, confirm your thermostat is set to “cool” or “heat.”

Then, check it’s telling the right equipment to run. This is typically 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 status. This feature keeps your unit from damaging short cycling. This may occur if you lose electricity.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump requires service. Call Service Experts Heating & Air Conditioning at 614-334-3192 for support.
  • 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. 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 needed.
  • 181/182—Install a new air filter. Clear the display by tapping “dismiss” after putting in a fresh filter.
  • 184—Put in a new humidifier pad. Clear the display 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 fresh filter.
  • 187—Rinse or put in a new ventilator filter. Clear the monitor by touching “dismiss” after putting in a fresh filter.
  • 188/189—Install a new UV bulb. Ring Service Experts Heating & Air Conditioning at 614-334-3192 for support.
  • 210—Register online for outdoor temperature. Get the Lyric app to do this step and ensure correct thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Use the Lyric app to complete 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 set up. Use the Lyric app and follow the process to connect your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump must be serviced service. Reach 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 help.
  • 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 needed.
  • 177—Indoor temperature sensor error. Call Service Experts Heating & Air Conditioning at 614-334-3192 for assistance.
  • 178—Outdoor temperature sensor error. Contact 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 screen by tapping “dismiss” after doing these procedures.
  • 184—Install a new humidifier pad. Clear the screen by hitting “dismiss” after installing pad filter.
  • 185—Install a new dehumidifier filter. Clear the thermostat by touching “dismiss” after installing a new filter.
  • 186—Rinse ventilator core. Clear the display by hitting “dismiss” after doing this task.
  • 187—Clean or replace ventilator filter. Clear the screen by hitting “dismiss” after buying a new filter.
  • 188/189—Install a new UV bulb. Get in touch with Service Experts Heating & Air Conditioning at 614-334-3192 for support.
  • 210—Register online for outside temperature. Download the Lyric app to finish 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 correct thermostat operation.
  • 399—No Internet. Check 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 up. Use 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 Support

If you’re still experiencing problems after trying the troubleshooting steps, our professionals are available to assist you. Call us at 614-334-3192 and we’ll be out rapidly to determine the malfunction.

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

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