How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the best thermostat manufacturers, and we proudly install them on a frequent basis in the U.S.. They’re durable and dependable. Plus, Honeywell is regularly updating its technology, resulting in more features for your residence.

However, every thermostat can have troubles occasionally. Due to this, we’ve prepared this helpful handbook to go over troubleshooting. While Honeywell thermostat troubleshooting problems are rare, they happen.

While you can usually fix most thermostat issues by yourself, they occasionally need Expert support. Our heating and cooling professionals are available to support you when you need us. We’re just a call away at 866-397-3787.

Let’s get started with the process by figuring out what kind of thermostat your residence has.

What Type of Thermostat Do I Have?

There are three models of thermostats:

    • Manual—This is the classic dial-shaped thermostat. You won’t experience error codes with this kind, but it’s also the least efficient for lowering utility expenses.
    • Programmable—This thermostat features a digital screen and arrows you press to set your desired temperature. You can also set daily programs to lower the temperature when you’re gone and set it higher when you return.
    • Smart—You won’t have to set any programs on this thermostat, because it learns your day. It instinctively adjusts the temperature when you or family members are gone to help you save on energy costs. You can also raise or lower the temperature anywhere via your phone or other Wi-Fi-enabled device.

As you’re aware most technologically advanced things, there are common malfunctions that may occur. Many of these troubles don’t require pro help and are easy to solve by yourself.

Common Honeywell Thermostat Troubleshooting Errors

Each Honeywell thermostat has a unique set of codes matching the malfunctions that take place.

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

Here are some of the most common Honeywell thermostat problems. These include the following programmable thermostats:

Display is Blank

If the display is blank on your programmable thermostat, you might need to replace the batteries. If that doesn’t solve the malfunction or you have a smart thermostat, there could be a wiring problem.

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

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

An unsecured panel may trigger the safety switch, which disconnects power to the unit.

Less frequently, an empty monitor could mean you need to replace your thermostat.

HVAC Unit Won’t Work

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

When it’s hot, confirm you schedule the thermostat below the ambient temperature. In the winter, verify it’s higher. This sounds absurd, but we’ve seen it take place a lot of times.

Ensure the power switch close to 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 trigger the safety switch, cutting off electricity to the system.

Unit still won’t run? Confirm circuit breakers haven’t tripped and that your HVAC unit isn’t showing error codes.

“Cool On” or “Heat On” is Flashing

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

Then, verify it’s telling the right equipment to run. This is usually demonstrated by “cool on,” “heat on” or an icon.

If this set of words or the illustration is pulsing, your thermostat is in a five-minute delay mode. This mode keeps your unit from damaging short cycling. This could occur 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 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 run.
    • 173—Thermostat temperature sensor error. Call Lyric technical support at 800-633-3991.
    • 175—AC power restarted. No action required.
    • 181/182—Replace air filter. Clear the screen by hitting “dismiss” after installing a fresh filter.
    • 184—Put in a new humidifier pad. Clear the screen by tapping “dismiss” after putting in a fresh pad filter.
    • 185—Install a new dehumidifier filter. Clear the monitor by hitting “dismiss” after putting in a fresh filter.
    • 187—Wash or put in a new ventilator filter. Clear the display by tapping “dismiss” after putting in a fresh 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 accurate thermostat operation.
    • 388—Register online for remote access and exterior temperature. Download the Lyric app to finish 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 choose new Wi-Fi network.
    • 508—Wi-Fi not set. Use the Lyric app and follow the procedure to configure your thermostat.

For more specifics, check 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. Call Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for assistance.
    • 170—Internal memory error. Reach Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for support.
    • 171—Set date and time. Finalize these settings so scheduling can work.
    • 173—Thermostat temperature sensor error. Contact Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for support.
    • 175—AC power resumed. No action necessary.
    • 177—Indoor temperature sensor error. Call Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for help.
    • 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 screen by touching “dismiss” after adding a new filter.
    • 183—Wash humidifier tank and add a new water filter. Clear the screen by hitting “dismiss” after finishing these tasks.
    • 184—Replace humidifier pad. Clear the monitor by touching “dismiss” after adding a new pad filter.
    • 185—Install a new dehumidifier filter. Clear the display by touching “dismiss” after installing a clean filter.
    • 186—Clean ventilator core. Clear the display by tapping “dismiss” after doing this task.
    • 187—Rinse or get a new ventilator filter. Clear the display by tapping “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 exterior temperature. Use the Lyric app to do this step and ensure accurate thermostat operation.
    • 388—Register online for remote access and exterior temperature. Download the Lyric app to finish 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 select new Wi-Fi network.
    • 508—Wi-Fi not connected. Get the Lyric app and follow the procedures to connect your thermostat.

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

Our Experts are Here to Provide Assistance

If you’re still having issues after going through the troubleshooting process, our Experts are ready to support you. Give us a call at 866-397-3787 and we’ll be out quickly to determine the problem.

If you have an aging thermostat, right now is a fantastic time to think about a replacement. Thermostat technology has come a long way lately Ask us for more information on how smart thermostats can make your house comfier while helping save on heating and cooling expenses all year.

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