How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the best thermostat producers, and we proudly install them on a frequent basis in Jackson. They’re sturdy and reliable. Plus, Honeywell is constantly updating its technology, resulting in more features for your household.

Still, all thermostats can run into errors every now and then. As a result, we’ve prepared this valuable guidebook to run through troubleshooting.

While you can usually repair the majority of thermostat problems by yourself, they often require Expert support. Our home comfort pros are available to assist you when you need us. We’re merely a call away at 601-852-3105.

Let’s begin the process by determining what model of thermostat your residence has.

What Model of Thermostat Do I Have?

There are three kinds of thermostats:

  • Manual—This is the typical dial-shaped thermostat. You won’t have error codes with this type, but it’s also the least efficient for reducing energy costs.
  • Programmable—This thermostat features a digital screen and arrows you press to determine your desired temperature. You can also choose daily programs to decrease the temperature when you’re gone and increase it when you get back.
  • Smart—You won’t have to set any programs on this thermostat, as it adjusts to your routine. It instinctively raises and lowers the temperature when you or family members are away to help you save on energy expenses. You can also change the temperature anywhere on your phone or other Wi-Fi-enabled device. 

As you’re aware the majority of technologically advanced products, there are several malfunctions that can occur. The majority of of these issues don’t need pro assistance and are easy to solve by yourself.

Common Honeywell Thermostat Troubles

All thermostats have a unique group of codes that correspond to the malfunctions that take place.

Think how simple it can be to repair a computer by restarting it. In most cases, troubleshooting a thermostat can be just as simple.

Here is a guide to the most common Honeywell thermostat errors. These involve the following programmable thermostats:

Display is Blank

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

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

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

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

While it’s less common, a blank display could mean you will need to buy a new thermostat.

HVAC System Won’t Run

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

In the summer, confirm you put the thermostat lower than the ambient temperature. When it’s cool, verify it’s higher. This sounds absurd, but we’ve seen it occur a lot of times.

Make sure the power switch by your indoor unit 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 open panel can activate the safety switch, cutting off power to the unit.

Unit still won’t run? Verify circuit breakers haven’t tripped and that your HVAC equipment isn’t showing error codes.

“Cool On” or “Heat On” is Flickering

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

Then, ensure it’s signaling the right equipment to start. This is typically demonstrated by “cool on,” “heat on” or a picture.

If this phrase or the illustration is pulsing, your thermostat is in a five-minute delay state. This setting protects your equipment 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 requires service. Call Comfortech Service Experts at 601-852-3105 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. Complete these settings so scheduling can occur.
  • 173—Thermostat temperature sensor error. Contact Lyric technical support at 800-633-3991.
  • 175—AC power restored. No action necessary.
  • 181/182—Put in a new air filter. Clear the thermostat by touching “dismiss” after putting in a clean filter.
  • 184—Install a new humidifier pad. Clear the screen by tapping “dismiss” after adding a new pad filter.
  • 185—Replace dehumidifier filter. Clear the screen by touching “dismiss” after installing a new filter.
  • 187—Rinse or put in a new ventilator filter. Clear the display by hitting “dismiss” after adding a fresh filter.
  • 188/189—Install a new UV bulb. Contact Comfortech Service Experts at 601-852-3105 for support.
  • 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 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 select new Wi-Fi network.
  • 508—Wi-Fi not set up. Get the Lyric app and follow the process to configure your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump must be serviced service. Reach Comfortech Service Experts at 601-852-3105 for assistance.
  • 168—Wi-Fi radio error. Call Comfortech Service Experts at 601-852-3105 for assistance.
  • 170—Internal memory error. Call Comfortech Service Experts at 601-852-3105 for assistance.
  • 171—Set date and time. Finalize these settings so scheduling can operate.
  • 173—Thermostat temperature sensor error. Call Comfortech Service Experts at 601-852-3105 for help.
  • 175—AC power reconnected. No action required.
  • 177—Indoor temperature sensor error. Call Comfortech Service Experts at 601-852-3105 for help.
  • 178—Outdoor temperature sensor error. Reach Comfortech Service Experts at 601-852-3105 for assistance.
  • 181/182—Get a new air filter. Clear the screen by hitting “dismiss” after installing a new filter.
  • 183—Rinse humidifier tank and add a new water filter. Clear the thermostat by tapping “dismiss” after finishing these tasks.
  • 184—Install a new humidifier pad. Clear the monitor by tapping “dismiss” after installing pad filter.
  • 185—Install a new dehumidifier filter. Clear the display by hitting “dismiss” after installing a clean filter.
  • 186—Clean ventilator core. Clear the screen by tapping “dismiss” after completing this task.
  • 187—Rinse or get a new ventilator filter. Clear the screen by hitting “dismiss” after installing a new filter.
  • 188/189—Replace UV bulb. Contact Comfortech Service Experts at 601-852-3105 for support.
  • 210—Register online for exterior temperature. Get the Lyric app to complete this step and ensure accurate thermostat operation.
  • 388—Register online for remote access and exterior temperature. Use the Lyric app to do 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 connected. Download the Lyric app and follow the steps to connect your thermostat.

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

Our Experts are Ready to Provide Assistance

If you’re still having issues after working through the troubleshooting list, our Experts are available to support you. Reach us at 601-852-3105 and we’ll come to your house as fast as we can to figure out the problem.

If you have an aging thermostat, now is a great time to think about a replacement. Thermostat technology has advanced over the last few years. Ask us for more details on how smart thermostats can make your house more convenient while helping save on energy bills throughout the year.

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