How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the leading thermostat manufacturers, and we proudly install them on a regular basis in the U.S.. They’re sturdy and trustworthy. In addition, Honeywell is regularly updating its technology, bringing more features for your family.

Nevertheless, each thermostat can experience troubles once in awhile. Due to this, we’ve put together this informative guidebook to go over troubleshooting. While Honeywell thermostat troubleshooting problems are rare, they do pop up.

While you can often fix most thermostat problems alone, they occasionally need Expert support. Our home comfort professionals are ready to help 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 typical dial-shaped thermostat. You won’t experience error codes with this kind, but it’s also the least efficient for reducing heating and cooling costs.
    • Programmable—This thermostat includes a digital screen and arrows you touch to set your desired temperature. You can also use daily programs to reduce the temperature when you’re gone and increase it when you return.
    • Smart—You won’t have to set any programs on this thermostat, as it picks up on your day. It intuitively adjusts the temperature when you or family members are gone to help you save on utility expenses. You can also raise or lower the temperature anywhere via your phone or other Wi-Fi-enabled device.

As you know most technologically advanced products, there are regular malfunctions that may occur. Most of these problems don’t call for professional assistance and are simple to repair by yourself.

Common Honeywell Thermostat Troubleshooting Issues

All Honeywell thermostats have a special kind of codes assigned to the glitches that take place.

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

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

Display is Blank

If the display is empty on your programmable thermostat, you may need to install new batteries. If that doesn’t fix the issue or you have a smart thermostat, there could be a wiring malfunction.

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

Additionally, you should make certain all furnace cabinet or air handler doors/panels are sturdily in place.

A panel that isn’t tight may trip the safety switch, which cuts off power to the system.

While it’s less common, an empty display could signify you should install a new thermostat.

HVAC Equipment Won’t Turn On

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

When it’s hot, make sure you set the thermostat below the ambient temperature. When it’s cool, make sure it’s higher. This sounds silly, but we’ve seen it take place 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 activate the safety switch, cutting off power to the unit.

Heating or cooling still won’t run? Confirm circuit breakers haven’t turned off and that your HVAC system isn’t showing error codes.

“Cool On” or “Heat On” is Blinking

To begin, ensure your thermostat is on “cool” or “heat.”

Then, check it’s signaling the correct equipment to run. This is usually shown by “cool on,” “heat on” or a picture.

If this set of words or the illustration is blinking, your thermostat is in a five-minute delay mode. This feature keeps your unit from damaging short cycling. This could happen 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. 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. Contact Lyric technical support at 800-633-3991.
    • 175—AC power restarted. No action necessary.
    • 181/182—Replace air filter. Clear the screen by tapping “dismiss” after putting in a fresh filter.
    • 184—Put in a new humidifier pad. Clear the monitor by hitting “dismiss” after putting in a new pad filter.
    • 185—Install a new dehumidifier filter. Clear the monitor by touching “dismiss” after installing a fresh filter.
    • 187—Wash or install a new ventilator filter. Clear the display by tapping “dismiss” after adding a fresh filter.
    • 188/189—Get a new UV bulb. Ring Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for help.
    • 210—Register online for outside temperature. Download the Lyric app to finish 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 pick new Wi-Fi network.
    • 508—Wi-Fi not configured. Download the Lyric app and follow the process to configure 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 & Plumbing at 866-397-3787 for help.
    • 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 support.
    • 171—Set date and time. Finalize these settings so scheduling can run.
    • 173—Thermostat temperature sensor error. Call Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for assistance.
    • 175—AC power restored. No action needed.
    • 177—Indoor temperature sensor error. Reach Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for assistance.
    • 178—Outdoor temperature sensor error. Contact Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for assistance.
    • 181/182—Replace air filter. Clear the screen by tapping “dismiss” after adding a new filter.
    • 183—Clean humidifier tank and add a new water filter. Clear the thermostat by touching “dismiss” after doing these steps.
    • 184—Get a new humidifier pad. Clear the thermostat by touching “dismiss” after adding a new pad filter.
    • 185—Install a new dehumidifier filter. Clear the thermostat by tapping “dismiss” after installing a fresh filter.
    • 186—Wash ventilator core. Clear the monitor by tapping “dismiss” after completing this task.
    • 187—Wash or get a new ventilator filter. Clear the screen by touching “dismiss” after installing a new filter.
    • 188/189—Replace UV bulb. Get in touch with Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for assistance.
    • 210—Register online for exterior temperature. Download the Lyric app to finish 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 correct 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 connected. Download the Lyric app and follow the procedures to connect your thermostat.

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

Our Experts are Available to Provide Support

If you’re still running into problems after trying the troubleshooting steps, our pros are here to assist you. Give us a call at 866-397-3787 and we’ll arrive as fast as we can to determine the malfunction.

If you rely on a dated thermostat, today is a good time to think about a new device. Thermostat technology has advanced in recent years Ask us for more info on how smart thermostats can make your residence more comfortable while helping save on heating and cooling expenses all year.

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