How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the top thermostat manufacturers, and we proudly install them on a regular basis in the U.S.. They’re durable and dependable. In addition, Honeywell is frequently updating its technology, resulting in more features for your residence.

Nevertheless, each thermostat can experience troubles every so often. As a result, we’ve prepared this useful guide to walk you through troubleshooting. While Honeywell thermostat troubleshooting problems are rare, they do pop up.

While you can usually solve most thermostat issues by yourself, they often call for Expert support. Our HVAC Experts are ready to assist you when you need us. We’re just a call away at 866-397-3787.

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

What Type of Thermostat Do I Have?

There are three models of thermostats:

    • Manual—This is the older dial-shaped thermostat. You won’t experience error codes with this one, but it’s also the least efficient for lowering heating and cooling bills.
    • Programmable—This thermostat includes a digital screen and arrows you touch to determine your desired temperature. You can also use daily programs to decrease the temperature when you’re at work and raise it when you return.
    • Smart—You won’t have to make any programs on this thermostat, as it adjusts to your schedule. It intuitively adjusts the temperature when you or other household members are out and about to help you save on heating and cooling costs. You can also raise or lower the temperature anywhere on your phone or other Wi-Fi-enabled device.

As is the case with the majority of technologically advanced things, there are regular glitches that can occur. Most of these troubles don’t call for professional assistance and are easy to repair on your own.

Common Honeywell Thermostat Troubleshooting Errors

All Honeywell thermostats have a unique group of codes that correspond to the malfunctions that happen.

Think how uncomplicated it can be to repair a computer by restarting it. Many times, correcting a thermostat can be just as uncomplicated.

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

Display is Blank

If the screen is blank on your programmable thermostat, you may need to replace the batteries. If that doesn’t fix the trouble or you have a smart thermostat, there may be a wiring issue.

Next, you should ensure the power is on for your furnace or air handler. Make sure the switch by the indoor system is in the “on” position.

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

A panel that isn’t tight may activate the safety switch, which stops power to the equipment.

While it’s less common, a clear screen may mean you should install a new thermostat.

Comfort Equipment Won’t Start

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

In the summer, make sure you schedule the thermostat lower than the room temperature. When it’s cold, verify it’s higher. This sounds absurd, but we’ve seen it happen lots of times.

Ensure the power switch by your indoor equipment is in the “on” position. You should also check the cabinet doors or panels are secure on your furnace cabinet or air handler. An open panel can activate the safety switch, diverting current to the system.

Equipment still won’t start? Make sure circuit breakers haven’t tripped and that your HVAC system isn’t experiencing error codes.

“Cool On” or “Heat On” is Blinking

First, verify your thermostat is switched to “cool” or “heat.”

Then, verify it’s telling the right equipment to start. This is typically shown by “cool on,” “heat on” or an illustration.

If these words or the illustration is blinking, your thermostat is in a five-minute delay status. This mode keeps your equipment from damaging short cycling. This can take place if you lose power.

Honeywell Thermostat-Specific Error Codes

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

    • 164—Heat pump needs service. Call Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for help.
    • 168—Wi-Fi radio error. Call 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 resumed. No action required.
    • 181/182—Install a new air filter. Clear the screen by tapping “dismiss” after adding a new filter.
    • 184—Install a new humidifier pad. Clear the monitor by hitting “dismiss” after putting in a fresh pad filter.
    • 185—Install a new dehumidifier filter. Clear the display by tapping “dismiss” after adding a fresh filter.
    • 187—Wash or install a new ventilator filter. Clear the display by touching “dismiss” after adding a new filter.
    • 188/189—Install a new UV bulb. Call Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for support.
    • 210—Register online for outside temperature. Use the Lyric app to complete 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 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 set up. Use the Lyric app and follow the procedure to configure your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005)

    • 164—Heat pump requires service. Call 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 support.
    • 170—Internal memory error. Reach Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for help.
    • 171—Set date and time. Finalize these settings so scheduling can operate.
    • 173—Thermostat temperature sensor error. Reach Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for help.
    • 175—AC power restored. No action required.
    • 177—Indoor temperature sensor error. Call Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for support.
    • 178—Outdoor temperature sensor error. Reach Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for assistance.
    • 181/182—Replace air filter. Clear the thermostat by hitting “dismiss” after adding a clean filter.
    • 183—Rinse humidifier tank and add a new water filter. Clear the monitor by hitting “dismiss” after completing these steps.
    • 184—Get a new humidifier pad. Clear the monitor by touching “dismiss” after installing pad filter.
    • 185—Install a new dehumidifier filter. Clear the display by hitting “dismiss” after putting in a new filter.
    • 186—Wash ventilator core. Clear the thermostat by hitting “dismiss” after finishing this task.
    • 187—Clean or get a new ventilator filter. Clear the display by touching “dismiss” after getting a new filter.
    • 188/189—Replace UV bulb. Get in touch with Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for help.
    • 210—Register online for outside temperature. Get the Lyric app to finish this step and ensure correct thermostat operation.
    • 388—Register online for remote access and outdoor temperature. Download the Lyric app to complete 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 set up. Get the Lyric app and follow the process to connect your thermostat.

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

Our Experts are Ready to Provide Support

If you’re still running into issues after working through the troubleshooting steps, our Experts are available to support you. Give us a call at 866-397-3787 and we’ll arrive as fast as we can to figure out the malfunction.

If you have an aging thermostat, now is a great time to think over a new thermostat. Thermostat technology has gotten better over the last few years. Ask us for more details on how smart thermostats can make your house more comfortable while helping save on energy costs throughout the year.

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