How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the best thermostat brands, and we proudly install them on a frequent basis in the U.S.. They’re sturdy and reliable. Plus, Honeywell is regularly advancing its technology, resulting in more features for your home.

Nevertheless, each thermostat can run into troubles at times. As a result, we’ve prepared this useful manual to walk you through troubleshooting. While Honeywell thermostat troubleshooting problems are rare, they do occur.

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

Let’s start the process by determining what kind of thermostat your house has.

What Kind of Thermostat Do I Have?

There are three types 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 reducing energy bills.
    • Programmable—This thermostat includes a digital screen and arrows you touch to set your desired temperature. You can also set daily programs to lower the temperature when you’re gone and raise it when you return.
    • Smart—You won’t have to make any programs on this thermostat, because it adjusts to your day. It intuitively adjusts the temperature when you or loved ones are out and about 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 the majority of technologically advanced solutions, there are regular malfunctions that might occur. Many of these situations don’t call for professional assistance and are simple to repair by yourself.

Common Honeywell Thermostat Troubleshooting Problems

All Honeywell thermostats have an exclusive kind of codes that correspond to the glitches that happen.

Think how simple it can be to restore a computer by restarting it. For the most part, troubleshooting a thermostat can be just as simple.

Here are some of the most encountered Honeywell thermostat errors. These apply to the following programmable thermostats:

Display is Blank

If the screen is blank on your programmable thermostat, you could need to get new batteries. If that doesn’t take care of the malfunction or you use a smart thermostat, there may be a wiring issue.

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

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

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

While it’s less common, a clear display may signify you need to buy a new thermostat.

Heating and Cooling System Won’t Run

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

During warm weather, verify you put the thermostat below the current temperature. When it’s cold, confirm it’s higher. This sounds silly, but we’ve seen it happen a lot of times.

Make sure the power switch by your indoor system is in the “on” position. You should also check the cabinet doors or panels are tight on your furnace cabinet or air handler. A loose panel can trigger the safety switch, diverting current to the unit.

System still won’t turn on? Confirm circuit breakers haven’t flipped and that your HVAC equipment isn’t displaying error codes.

“Cool On” or “Heat On” is Blinking

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

Then, verify it’s signaling the appropriate unit to turn on. This is usually shown by “cool on,” “heat on” or an icon.

If these words or the picture is blinking, your thermostat is in a five-minute delay mode. This setting stops your equipment from harmful short cycling. This may 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. Reach Lyric technical support at 800-633-3991. 170—Internal memory error. Contact Lyric technical support at 800-633-3991.
    • 171—Set date and time. Finish these settings so scheduling can run.
    • 173—Thermostat temperature sensor error. Reach Lyric technical support at 800-633-3991.
    • 175—AC power restarted. No action needed.
    • 181/182—Put in a new air filter. Clear the thermostat by hitting “dismiss” after putting in a fresh filter.
    • 184—Install a new humidifier pad. Clear the monitor by touching “dismiss” after adding a new pad filter.
    • 185—Install a new dehumidifier filter. Clear the display by tapping “dismiss” after putting in a fresh filter.
    • 187—Clean or put in a new ventilator filter. Clear the screen by hitting “dismiss” after adding a fresh filter.
    • 188/189—Install a new UV bulb. Ring Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for support.
    • 210—Register online for outdoor temperature. Get the Lyric app to complete this step and ensure accurate thermostat operation.
    • 388—Register online for remote access and outside 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 pick new Wi-Fi network.
    • 508—Wi-Fi not configured. Download the Lyric app and follow the process to configure your thermostat.

For more details, 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 assistance.
    • 168—Wi-Fi radio error. Contact Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for help.
    • 170—Internal memory error. Contact Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for assistance.
    • 171—Set date and time. Finalize these settings so scheduling can run.
    • 173—Thermostat temperature sensor error. Reach Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for assistance.
    • 175—AC power resumed. No action necessary.
    • 177—Indoor temperature sensor error. Reach 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 assistance.
    • 181/182—Replace air filter. Clear the thermostat by touching “dismiss” after installing a clean filter.
    • 183—Clean humidifier tank and add a new water filter. Clear the display by tapping “dismiss” after finishing these tasks.
    • 184—Install a new humidifier pad. Clear the display by touching “dismiss” after adding a new pad filter.
    • 185—Get a new dehumidifier filter. Clear the screen by tapping “dismiss” after adding a new filter.
    • 186—Wash ventilator core. Clear the monitor by touching “dismiss” after finishing this task.
    • 187—Wash or get a new ventilator filter. Clear the display by hitting “dismiss” after getting a new filter.
    • 188/189—Get a new UV bulb. Reach Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for support.
    • 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 outdoor temperature. Download the Lyric app to do this step and ensure correct thermostat operation.
    • 399—No Internet. Confirm your network settings.
    • 400—No Wi-Fi signal. Wait for the thermostat to reconnect or pick new Wi-Fi network.
    • 508—Wi-Fi not set up. Download the Lyric app and follow the process to connect your thermostat.

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

Our Experts are Here to Provide Assistance

If you’re still experiencing troubles after going through the troubleshooting process, our pros are available to assist you. Reach us at 866-397-3787 and we’ll arrive rapidly to figure out the issue.

If you use a dated thermostat, now is a fantastic time to think about a replacement. Thermostat technology has advanced lately Ask us for more details on how smart thermostats can make your home more comfortable while helping save on heating and cooling bills throughout the year.

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