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 durable and reliable. Also, Honeywell is frequently improving its technology, resulting in more features for your residence.

Still, all thermostats can run into troubles every so often. As a result, we’ve compiled this useful handbook to run through troubleshooting. While Honeywell thermostat troubleshooting problems are rare, they do pop up.

While you can usually solve many thermostat issues on your own, they often require Expert assistance. Our HVAC professionals are ready to help when you need us. We’re only a call away at 866-397-3787.

Let’s start the process by finding out what kind of thermostat your residence has.

What Kind of Thermostat Do I Have?

There are three kinds of thermostats:

    • Manual—This is the classic dial-shaped thermostat. You won’t run into error codes with this kind, but it’s also the least efficient for lowering utility costs.
    • Programmable—This thermostat has 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 away and increase it when you return.
    • Smart—You won’t have to schedule any programs on this thermostat, because it learns your schedule. It automatically adjusts the temperature when you or loved ones are gone to help you save on utility costs. You can also raise or lower the temperature anywhere using your phone or other Wi-Fi-enabled device.

As you’re aware the majority of technologically advanced solutions, there are several problems that might take place. Most of these situations don’t require professional help and are uncomplicated enough to fix on your own.

Common Honeywell Thermostat Troubleshooting Problems

Each Honeywell thermostat has a special group of codes matching the problems that take place.

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

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

Display is Blank

If the screen is empty on your programmable thermostat, you could need to get new batteries. If that doesn’t fix the malfunction or you use a smart thermostat, there might be a wiring problem.

Next, you should make sure the power is flowing for your furnace or air handler. Confirm the switch near the indoor equipment is in the “on” position.

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

A loose panel may trip the safety switch, which disconnects power to the unit.

Less frequently, a clear display can signify you should install a new thermostat.

Comfort Unit Won’t Turn On

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

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

Ensure the power switch near 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 open panel can activate the safety switch, diverting current to the unit.

System still won’t start? Confirm circuit breakers haven’t turned off and that your HVAC system isn’t showing error codes.

“Cool On” or “Heat On” is Flickering

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

Then, verify it’s calling for the right equipment to turn on. This is usually indicated by “cool on,” “heat on” or a picture.

If this phrase or the icon is pulsing, your thermostat is in a five-minute delay status. This mode stops your equipment 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. 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. Finalize these settings so scheduling can take place.
    • 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 display by hitting “dismiss” after installing a fresh filter.
    • 184—Put in a new humidifier pad. Clear the monitor by touching “dismiss” after adding a fresh pad filter.
    • 185—Install a new dehumidifier filter. Clear the display by tapping “dismiss” after putting in a fresh filter.
    • 187—Wash or replace ventilator filter. Clear the screen by tapping “dismiss” after adding a clean filter.
    • 188/189—Replace UV bulb. Contact Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for help.
    • 210—Register online for exterior temperature. Use the Lyric app to finish this step and ensure accurate thermostat operation.
    • 388—Register online for remote access and outdoor temperature. Download 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 configured. Get the Lyric app and follow the procedure to connect your thermostat.

For more details, check 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 assistance.
    • 168—Wi-Fi radio error. Call Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for assistance.
    • 170—Internal memory error. Call Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for help.
    • 171—Set date and time. Complete these settings so scheduling can operate.
    • 173—Thermostat temperature sensor error. Contact Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for help.
    • 175—AC power resumed. No action needed.
    • 177—Indoor temperature sensor error. Call Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for support.
    • 178—Outdoor temperature sensor error. Contact Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for support.
    • 181/182—Install a new air filter. Clear the monitor by hitting “dismiss” after installing a new filter.
    • 183—Rinse humidifier tank and install a new water filter. Clear the display by hitting “dismiss” after finishing these steps.
    • 184—Install a new humidifier pad. Clear the display by hitting “dismiss” after installing pad filter.
    • 185—Replace dehumidifier filter. Clear the display by touching “dismiss” after adding a fresh filter.
    • 186—Rinse ventilator core. Clear the thermostat by tapping “dismiss” after finishing this task.
    • 187—Clean or get a new ventilator filter. Clear the screen by touching “dismiss” after buying a new filter.
    • 188/189—Install 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 do this step and ensure accurate thermostat operation.
    • 388—Register online for remote access and outdoor temperature. Download the Lyric app to finish this step and ensure correct 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 connected. Download the Lyric app and follow the steps to connect your thermostat.

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

Our Experts are Available to Provide Assistance

If you’re still running into troubles after trying the troubleshooting process, our professionals are ready to help. Reach us at 866-397-3787 and we’ll be out as fast as we can to diagnose the malfunction.

If you use an aging thermostat, now is a great time to consider a replacement. Thermostat technology has gotten better over the last few years. Ask us for more info on how smart thermostats can make your house comfier while helping save on heating and cooling expenses throughout the year.

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