How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the top thermostat producers, and we proudly install them on a frequent basis in the U.S.. They’re sturdy and reliable. Also, Honeywell is constantly updating its technology, bringing more features for your residence.

Still, all thermostats can have problems at times. That’s why we’ve put together this useful guide to run through troubleshooting. While Honeywell thermostat troubleshooting problems are rare, they do occur.

While you can often solve most thermostat issues by yourself, they sometimes call for Expert help. Our heating and cooling professionals are ready to support you when you need us. We’re only a call away at 866-397-3787.

Let’s get started with the process by determining what model of thermostat your home 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 have error codes with this one, but it’s also the least efficient for reducing heating and cooling expenses.
    • Programmable—This thermostat includes a digital screen and arrows you use to set your desired temperature. You can also set daily programs to lower the temperature when you’re at work and raise it when you get back.
    • Smart—You won’t have to make any programs on this thermostat, as it adjusts to your routine. It intuitively adjusts the temperature when you or loved ones are gone to help you save on heating and cooling costs. You can also change the temperature anywhere using your phone or other Wi-Fi-enabled device.

As is the case with many technologically advanced products, there are common malfunctions that may take place. The majority of of these problems don’t call for pro support and are simple to solve on your own.

Common Honeywell Thermostat Troubleshooting Errors

Every Honeywell thermostat has a unique set of codes assigned to the malfunctions that happen.

Think how simple it can be to restore a computer by restarting it. In many instances, troubleshooting a thermostat can be just as uncomplicated.

Here is a listing the most reported Honeywell thermostat issues. These include the following programmable thermostats:

Display is Blank

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

Next, you should check the power is flowing for your furnace or air handler. Make sure the switch near the indoor equipment is switched “up”.

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

An unsecured panel may trigger the safety switch, which disconnects power to the equipment.

While it’s less common, a blank screen could signify you need to replace your thermostat.

Heating and Cooling System Won’t Work

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

During warm weather, verify you schedule the thermostat beneath the current temperature. When it’s cool, make sure it’s higher. This sounds silly, but we’ve seen it take place many times.

Make sure the power switch close to your indoor equipment is in the “on” position. You should also check the cabinet doors or panels are tight on your furnace cabinet or air handler. An unsecured panel can trip the safety switch, stopping current to the system.

System still won’t run? Make sure circuit breakers haven’t tripped and that your HVAC unit isn’t showing error codes.

“Cool On” or “Heat On” is Flickering

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

Then, verify it’s calling for the appropriate equipment to start. This is often shown by “cool on,” “heat on” or an illustration.

If these words or the illustration is flashing, your thermostat is in a five-minute delay mode. This feature stops your system from bad short cycling. This may take place if your power is interrupted.

Honeywell Thermostat-Specific Error Codes

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

    • 164—Heat pump requires service. Call Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for assistance.
    • 168—Wi-Fi radio error. Reach 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 occur.
    • 173—Thermostat temperature sensor error. Call Lyric technical support at 800-633-3991.
    • 175—AC power resumed. No action required.
    • 181/182—Replace air filter. Clear the monitor by touching “dismiss” after putting in a clean filter.
    • 184—Install a new humidifier pad. Clear the monitor by touching “dismiss” after adding a clean pad filter.
    • 185—Install a new dehumidifier filter. Clear the monitor by touching “dismiss” after putting in a new filter.
    • 187—Rinse or put in a new ventilator filter. Clear the display by hitting “dismiss” after installing a fresh filter.
    • 188/189—Get a new UV bulb. Contact Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for help.
    • 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 exterior temperature. Download the Lyric app to do this step and ensure proper thermostat operation.
    • 399—No Internet. Check 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. Download the Lyric app and follow the steps to connect your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005)

    • 164—Heat pump requires service. Reach Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for support.
    • 168—Wi-Fi radio error. Reach Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for assistance.
    • 170—Internal memory error. Contact Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for help.
    • 171—Set date and time. Complete these settings so scheduling can run.
    • 173—Thermostat temperature sensor error. Reach Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for help.
    • 175—AC power resumed. No action needed.
    • 177—Indoor temperature sensor error. Contact Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for assistance.
    • 178—Outdoor temperature sensor error. Reach Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for assistance.
    • 181/182—Install a new air filter. Clear the thermostat by hitting “dismiss” after putting in a new filter.
    • 183—Rinse humidifier tank and add a new water filter. Clear the display by tapping “dismiss” after finishing these tasks.
    • 184—Replace humidifier pad. Clear the monitor by hitting “dismiss” after installing pad filter.
    • 185—Install a new dehumidifier filter. Clear the screen by touching “dismiss” after putting in a fresh filter.
    • 186—Clean ventilator core. Clear the screen by hitting “dismiss” after doing this task.
    • 187—Clean or install a new ventilator filter. Clear the screen by touching “dismiss” after buying a new filter.
    • 188/189—Replace UV bulb. Contact Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for assistance.
    • 210—Register online for exterior temperature. Download the Lyric app to do this step and ensure correct thermostat operation.
    • 388—Register online for remote access and exterior temperature. Download the Lyric app to finish 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 select 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 Available to Provide Support

If you’re still running into issues after trying the troubleshooting process, our pros are ready to support you. Call us at 866-397-3787 and we’ll be out quickly to diagnose the problem.

If you rely on a dated thermostat, today is a great time to consider a replacement. Thermostat technology has gotten better in recent years Ask us for more info on how smart thermostats can make your home comfier while helping save on utility bills throughout the year.

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