How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the top thermostat producers, and we proudly install them on a regular basis in the U.S.. They’re durable and trustworthy. Plus, Honeywell is regularly advancing its technology, resulting in more features for your household.

Nevertheless, all thermostats can have troubles every now and then. That’s why we’ve put together this helpful guidebook to walk you through troubleshooting. While Honeywell thermostat troubleshooting problems are rare, they do occur.

While you can typically solve most thermostat problems on your own, they sometimes call for Expert help. Our heating and cooling Experts are ready to support you when you need us. We’re merely a call away at 866-397-3787.

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

What Kind of Thermostat Do I Have?

There are three kinds of thermostats:

    • Manual—This is the older dial-shaped thermostat. You won’t experience error codes with this type, but it’s also the least efficient for saving on utility expenses.
    • Programmable—This thermostat has a digital screen and arrows you touch to set your desired temperature. You can also choose daily programs to lower the temperature when you’re at work and set it higher when you return.
    • Smart—You won’t have to set any programs on this thermostat, as it picks up on your schedule. It intuitively raises and lowers the temperature when you or loved ones are out and about to help you save on energy bills. 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 things, there are regular malfunctions that might occur. The majority of of these troubles don’t need Expert help and are uncomplicated enough to solve by yourself.

Common Honeywell Thermostat Troubleshooting Errors

Each Honeywell thermostat has a special set of codes that correspond to the problems that happen.

Think how simple it can be to restore a computer by restarting it. In most cases, diagnosing a thermostat can be just as uncomplicated.

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

Display is Blank

If the monitor is blank on your programmable thermostat, you could need to put in new batteries. If that doesn’t take care of the malfunction or you have a smart thermostat, there might be a wiring malfunction.

Next, you should check the power is flowing for your furnace or air handler. Confirm the switch near the indoor unit is switched “on”.

Also, you should confirm all furnace cabinet or air handler doors/panels are securely secured.

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

Infrequently, a blank monitor may indicate you should get a new thermostat.

Heating and Cooling Unit Won’t Turn On

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

During warm weather, confirm you put the thermostat lower than the ambient temperature. When it’s cool, verify it’s higher. This sounds silly, but we’ve seen it take place many times.

Ensure the power switch near your indoor unit is in the “on” position. You should also check the cabinet doors or panels are closed on your furnace cabinet or air handler. An unsecured panel can activate the safety switch, cutting off current to the system.

Equipment still won’t turn on? Confirm circuit breakers haven’t turned off and that your HVAC equipment isn’t showing error codes.

“Cool On” or “Heat On” is Flickering

To start, make sure your thermostat is switched to “cool” or “heat.”

Then, make sure it’s signaling the appropriate system to turn on. This is often demonstrated by “cool on,” “heat on” or an illustration.

If this phrase or the picture is blinking, your thermostat is in a five-minute delay status. This feature stops your unit from bad short cycling. This can happen if you lose power.

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 support.
    • 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. Finalize these settings so scheduling can take place.
    • 173—Thermostat temperature sensor error. Contact Lyric technical support at 800-633-3991.
    • 175—AC power resumed. No action necessary.
    • 181/182—Install a new air filter. Clear the display by touching “dismiss” after putting in a new filter.
    • 184—Put in a new humidifier pad. Clear the screen by hitting “dismiss” after installing a fresh pad filter.
    • 185—Replace dehumidifier filter. Clear the monitor by touching “dismiss” after putting in a clean filter.
    • 187—Clean or install a new ventilator filter. Clear the thermostat by tapping “dismiss” after installing a new filter.
    • 188/189—Install a new UV bulb. Call Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for assistance.
    • 210—Register online for outdoor temperature. Get the Lyric app to do this step and ensure accurate thermostat operation.
    • 388—Register online for remote access and outside temperature. Use the Lyric app to do 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. Use the Lyric app and follow the process to configure your thermostat.

For more specifics, look at 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 & Plumbing at 866-397-3787 for assistance.
    • 168—Wi-Fi radio error. Contact Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for support.
    • 170—Internal memory error. Contact Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for help.
    • 171—Set date and time. Finish these settings so scheduling can run.
    • 173—Thermostat temperature sensor error. Contact Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for help.
    • 175—AC power restored. No action required.
    • 177—Indoor temperature sensor error. Contact Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for assistance.
    • 178—Outdoor temperature sensor error. Call Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for help.
    • 181/182—Install a new air filter. Clear the display by hitting “dismiss” after putting in a fresh filter.
    • 183—Clean humidifier tank and add a new water filter. Clear the monitor by touching “dismiss” after completing these steps.
    • 184—Replace humidifier pad. Clear the thermostat by touching “dismiss” after getting a new pad filter.
    • 185—Get a new dehumidifier filter. Clear the monitor by tapping “dismiss” after adding a clean filter.
    • 186—Rinse ventilator core. Clear the display by touching “dismiss” after completing this task.
    • 187—Rinse or replace ventilator filter. Clear the monitor by touching “dismiss” after getting a new filter.
    • 188/189—Add a new UV bulb. Get in touch with Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for assistance.
    • 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 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 pick new Wi-Fi network.
    • 508—Wi-Fi not configured. Use the Lyric app and follow the process to connect your thermostat.

For more specifics, look at this thermostat’s user manual.

Our Experts are Here to Provide Support

If you’re still running into issues after going through the troubleshooting list, our pros are here to help. Call us at 866-397-3787 and we’ll arrive as fast as we can to diagnose the issue.

If you use an aging thermostat, today is a good time to think over a new device. Thermostat technology has come a long way over the last few years. Ask us for more info on how smart thermostats can make your home more comfortable while helping save on energy bills throughout the year.

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