How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the best thermostat brands, and we proudly install them on a usual basis in the U.S.. They’re durable and trustworthy. In addition, Honeywell is frequently enhancing its technology, resulting in more features for your household.

Nevertheless, every thermostat can have issues every so often. As a result, we’ve prepared this helpful manual to walk you through troubleshooting. While Honeywell thermostat troubleshooting problems are rare, they do occur.

While you can often fix most thermostat troubles on your own, they sometimes call for Expert support. Our home comfort Experts are here to assist you when you need us. We’re only a call away at 866-397-3787.

Let’s get started with the process by determining what model of thermostat your house has.

What Model of Thermostat Do I Have?

There are three models of thermostats:

    • Manual—This is the older dial-shaped thermostat. You won’t run into error codes with this one, but it’s also the least efficient for saving on utility costs.
    • Programmable—This thermostat features a digital screen and arrows you use to set your desired temperature. You can also set daily programs to reduce the temperature when you’re at work and set it higher when you get back.
    • Smart—You won’t have to make any programs on this thermostat, since it adjusts to your day. It automatically raises and lowers the temperature when you or other household members are out and about to help you save on utility costs. You can also adjust the temperature anywhere using your phone or other Wi-Fi-enabled device.

As is the case with the majority of technologically advanced things, there are regular problems that can happen. Most of these issues don’t need pro support and are easy to repair by yourself.

Common Honeywell Thermostat Troubleshooting Errors

Every Honeywell thermostat has a special group of codes matching the glitches that occur.

Think how easy it can be to fix a computer by restarting it. In most situations, diagnosing a thermostat can be just as uncomplicated.

Here is a listing the most common Honeywell thermostat problems. These involve the following programmable thermostats:

Display is Blank

If the screen is empty on your programmable thermostat, you might need to install new batteries. If that doesn’t solve the malfunction or you rely on a smart thermostat, there may be a wiring malfunction.

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

Additionally, you should confirm all furnace cabinet or air handler doors/panels are tightly in place.

A panel that isn’t tight may trigger the safety switch, which cuts off power to the unit.

Infrequently, a clear display might mean you will need to replace your thermostat.

Comfort System Won’t Turn On

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

During warm weather, make sure you put the thermostat lower than the room temperature. In the winter, verify it’s higher. This sounds absurd, but we’ve seen it happen lots of times.

Confirm the power switch by your indoor equipment is in the “on” position. You should also make sure the cabinet doors or panels are closed on your furnace cabinet or air handler. An unsecured panel can trigger the safety switch, diverting current to the unit.

Heating or cooling still won’t turn on? Make sure circuit breakers haven’t turned off and that your HVAC unit isn’t showing error codes.

“Cool On” or “Heat On” is Blinking

To start, confirm your thermostat is on “cool” or “heat.”

Then, make sure it’s telling the correct equipment to turn on. This is typically demonstrated by “cool on,” “heat on” or a picture.

If this set of words or the illustration is pulsing, your thermostat is in a five-minute delay state. This feature keeps your equipment from damaging 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. 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. Complete these settings so scheduling can occur.
    • 173—Thermostat temperature sensor error. Contact Lyric technical support at 800-633-3991.
    • 175—AC power resumed. No action necessary.
    • 181/182—Replace air filter. Clear the monitor by touching “dismiss” after adding a new filter.
    • 184—Replace humidifier pad. Clear the screen by touching “dismiss” after putting in a fresh pad filter.
    • 185—Install a new dehumidifier filter. Clear the thermostat by hitting “dismiss” after installing a clean filter.
    • 187—Clean or install a new ventilator filter. Clear the monitor by tapping “dismiss” after putting in a new filter.
    • 188/189—Install a new UV bulb. Ring Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for help.
    • 210—Register online for outside temperature. Download the Lyric app to complete this step and ensure correct thermostat operation.
    • 388—Register online for remote access and exterior temperature. Get the Lyric app to complete 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 configured. Get the Lyric app and follow the process to connect your thermostat.

For more details, look at 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 support.
    • 168—Wi-Fi radio error. Call Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for help.
    • 170—Internal memory error. Call 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. Reach Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for assistance.
    • 175—AC power restored. No action required.
    • 177—Indoor temperature sensor error. Contact Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for assistance.
    • 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 touching “dismiss” after installing a clean filter.
    • 183—Rinse humidifier tank and install a new water filter. Clear the thermostat by touching “dismiss” after doing these procedures.
    • 184—Install a new humidifier pad. Clear the screen by touching “dismiss” after adding a new pad filter.
    • 185—Install a new dehumidifier filter. Clear the thermostat by tapping “dismiss” after putting in a new filter.
    • 186—Rinse ventilator core. Clear the thermostat by touching “dismiss” after finishing this task.
    • 187—Rinse or replace ventilator filter. Clear the screen by tapping “dismiss” after installing a new filter.
    • 188/189—Replace UV bulb. Contact 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. Get 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 configured. Use the Lyric app and follow the procedures to connect your thermostat.

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

Our Experts are Here to Help

If you’re still running into troubles after working through the troubleshooting list, our professionals are ready to support you. Call us at 866-397-3787 and we’ll be out quickly to figure out the issue.

If you have an aging thermostat, right now is a fantastic time to think over a new thermostat. Thermostat technology has advanced lately Ask us for more information on how smart thermostats can make your house better while helping save on energy costs throughout the year.

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