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 sturdy and reliable. In addition, Honeywell is constantly improving its technology, offering more features for your household.

Still, all thermostats can experience problems at times. Due to this, we’ve prepared this useful handbook to walk you through troubleshooting. While Honeywell thermostat troubleshooting problems are rare, they do pop up.

While you can typically repair the majority of thermostat problems on your own, they occasionally require Expert help. Our heating and cooling pros are available to assist you when you need us. We’re just a call away at 866-397-3787.

Let’s start the process by figuring out what model of thermostat your home has.

What Type of Thermostat Do I Have?

There are three models of thermostats:

    • Manual—This is the typical dial-shaped thermostat. You won’t run into error codes with this one, but it’s also the least efficient for reducing energy bills.
    • Programmable—This thermostat has a digital screen and arrows you press to set your desired temperature. You can also use daily programs to decrease the temperature when you’re at work and increase it when you come home.
    • Smart—You won’t have to set any programs on this thermostat, as it adjusts to your routine. It intuitively adjusts the temperature when you or loved ones are away to help you save on utility bills. You can also adjust the temperature anywhere using your phone or other Wi-Fi-enabled device.

As you’re aware most technologically advanced products, there are several glitches that may take place. Most of these situations don’t need pro assistance and are simple to solve on your own.

Common Honeywell Thermostat Troubleshooting Errors

Each Honeywell thermostat has a special group of codes that correspond to the malfunctions that take place.

Think how simple it can be to restore a computer by restarting it. Many times, troubleshooting a thermostat can be just as uncomplicated.

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

Display is Blank

If the monitor is empty on your programmable thermostat, you may need to put in new batteries. If that doesn’t fix the trouble or you rely on a smart thermostat, there may be a wiring problem.

Next, you should make sure the power is on for your furnace or air handler. Verify the switch by the indoor unit is in the “on” position.

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

A loose panel may activate the safety switch, which cuts off power to the unit.

Infrequently, a blank display might signify you should buy a new thermostat.

Comfort Equipment Won’t Run

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

In the summer, verify you schedule the thermostat beneath the current temperature. When it’s cold, make sure it’s higher. This sounds silly, but we’ve seen it take place many 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 closed on your furnace cabinet or air handler. A loose panel can trip the safety switch, cutting off electricity to the equipment.

System still won’t run? Make sure circuit breakers haven’t flipped and that your HVAC equipment isn’t showing error codes.

“Cool On” or “Heat On” is Blinking

First, confirm your thermostat is set to “cool” or “heat.”

Then, make sure it’s calling for the right equipment to run. This is typically demonstrated by “cool on,” “heat on” or a picture.

If these words or the icon is pulsing, your thermostat is in a five-minute delay state. This mode stops your unit from harmful short cycling. This could happen if you lose electricity.

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. Contact 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. Call Lyric technical support at 800-633-3991.
    • 175—AC power restored. No action necessary.
    • 181/182—Install a new air filter. Clear the thermostat by touching “dismiss” after adding a new filter.
    • 184—Replace humidifier pad. Clear the screen by hitting “dismiss” after installing a fresh pad filter.
    • 185—Put in a new dehumidifier filter. Clear the monitor by touching “dismiss” after installing a fresh filter.
    • 187—Clean or install a new ventilator filter. Clear the thermostat by touching “dismiss” after adding a fresh filter.
    • 188/189—Install a new UV bulb. Call Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for assistance.
    • 210—Register online for outdoor temperature. Download the Lyric app to finish this step and ensure accurate thermostat operation.
    • 388—Register online for remote access and exterior temperature. Get the Lyric app to finish 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 pick new Wi-Fi network.
    • 508—Wi-Fi not set up. Get the Lyric app and follow the steps to configure your thermostat.

For more information, 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 assistance.
    • 170—Internal memory error. Contact Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for support.
    • 171—Set date and time. Complete these settings so scheduling can work.
    • 173—Thermostat temperature sensor error. Call 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 help.
    • 178—Outdoor temperature sensor error. Reach Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for support.
    • 181/182—Install a new air filter. Clear the thermostat by touching “dismiss” after adding a new filter.
    • 183—Clean humidifier tank and install a new water filter. Clear the screen by hitting “dismiss” after doing these procedures.
    • 184—Replace humidifier pad. Clear the display by tapping “dismiss” after adding a new pad filter.
    • 185—Get a new dehumidifier filter. Clear the display by hitting “dismiss” after adding a clean filter.
    • 186—Wash ventilator core. Clear the display by tapping “dismiss” after finishing this task.
    • 187—Wash or install a new ventilator filter. Clear the screen by hitting “dismiss” after getting a new filter.
    • 188/189—Replace UV bulb. Contact Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for assistance.
    • 210—Register online for outdoor temperature. Download the Lyric app to finish this step and ensure accurate thermostat operation.
    • 388—Register online for remote access and outdoor temperature. Get the Lyric app to complete this step and ensure accurate 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 connected. Download the Lyric app and follow the procedures to connect your thermostat.

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

Our Experts are Ready to Provide Assistance

If you’re still running into troubles after going through the troubleshooting list, our Experts are available to support you. Give us a call at 866-397-3787 and we’ll be out as fast as we can to diagnose the problem.

If you have an aging thermostat, now is a good time to think about a replacement. Thermostat technology has advanced lately Ask us for more information on how smart thermostats can make your home more comfortable while helping save on energy expenses all year.

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