How to Troubleshoot Honeywell Thermostat Errors

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

Still, each thermostat can run into troubles now and then. Due to this, we’ve prepared this helpful manual to go over troubleshooting. While Honeywell thermostat troubleshooting problems are rare, they happen.

While you can typically repair most thermostat troubles by yourself, they sometimes require Expert help. Our home comfort pros are here to support you when you need us. We’re just a call away at 866-397-3787.

Let’s start the process by finding out what type of thermostat your residence 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 run into error codes with this kind, but it’s also the least efficient for lowering heating and cooling expenses.
    • Programmable—This thermostat has a digital screen and arrows you use to set your desired temperature. You can also set daily programs to decrease the temperature when you’re at work and set it higher when you return.
    • Smart—You won’t have to schedule any programs on this thermostat, since it adjusts to your routine. It instinctively adjusts the temperature when you or loved ones are away to help you save on energy bills. You can also adjust the temperature anywhere via your phone or other Wi-Fi-enabled device.

As you know many technologically advanced things, there are regular problems that might occur. Most of these issues don’t call for pro assistance and are easy to fix by yourself.

Common Honeywell Thermostat Troubleshooting Errors

Each Honeywell thermostat has an exclusive group of codes that correspond to the malfunctions that take place.

Think how simple it can be to repair a computer by restarting it. In most cases, correcting a thermostat can be just as uncomplicated.

Here is a listing the most reported Honeywell thermostat issues. These involve the following programmable thermostats:

Display is Blank

If the monitor is clear on your programmable thermostat, you might need to put in new batteries. If that doesn’t fix the trouble or you use a smart thermostat, there could be a wiring malfunction.

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

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

An unsecured panel may trip the safety switch, which cuts off power to the unit.

Infrequently, an empty monitor could mean you will need to get a new thermostat.

HVAC Unit Won’t Turn On

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

When it’s hot, verify you put the thermostat beneath the current temperature. In the winter, make sure it’s higher. This sounds silly, but we’ve seen it happen lots of times.

Ensure the power switch near your indoor unit is in the “on” position. You should also check the cabinet doors or panels are tight on your furnace cabinet or air handler. An open panel can trip the safety switch, stopping power to the unit.

Equipment still won’t turn on? Confirm circuit breakers haven’t flipped and that your HVAC system isn’t showing error codes.

“Cool On” or “Heat On” is Flashing

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

Then, make sure it’s signaling the appropriate equipment to turn on. This is often indicated by “cool on,” “heat on” or an icon.

If this phrase or the icon is blinking, your thermostat is in a five-minute delay mode. This feature keeps your unit from harmful short cycling. This could occur 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 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 take place.
    • 173—Thermostat temperature sensor error. Call Lyric technical support at 800-633-3991.
    • 175—AC power restored. No action needed.
    • 181/182—Put in a new air filter. Clear the display by touching “dismiss” after installing a clean filter.
    • 184—Replace humidifier pad. Clear the monitor by tapping “dismiss” after putting in a fresh pad filter.
    • 185—Put in a new dehumidifier filter. Clear the screen by tapping “dismiss” after adding a clean filter.
    • 187—Clean or install a new ventilator filter. Clear the thermostat by hitting “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 outdoor temperature. Get the Lyric app to finish this step and ensure correct thermostat operation.
    • 388—Register online for remote access and outside temperature. Get 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 select new Wi-Fi network.
    • 508—Wi-Fi not configured. Download the Lyric app and follow the process to configure your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005)

    • 164—Heat pump needs service. Call 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 support.
    • 170—Internal memory error. Reach Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for help.
    • 171—Set date and time. Complete these settings so scheduling can operate.
    • 173—Thermostat temperature sensor error. Contact Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for assistance.
    • 175—AC power resumed. No action necessary.
    • 177—Indoor temperature sensor error. Contact Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for support.
    • 178—Outdoor temperature sensor error. Call Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for assistance.
    • 181/182—Get a new air filter. Clear the screen by tapping “dismiss” after installing a new filter.
    • 183—Wash humidifier tank and install a new water filter. Clear the monitor by hitting “dismiss” after doing these tasks.
    • 184—Replace humidifier pad. Clear the screen by tapping “dismiss” after getting a new pad filter.
    • 185—Install a new dehumidifier filter. Clear the monitor by tapping “dismiss” after putting in a clean filter.
    • 186—Wash ventilator core. Clear the thermostat by hitting “dismiss” after completing this task.
    • 187—Rinse or replace ventilator filter. Clear the screen by hitting “dismiss” after buying a new filter.
    • 188/189—Install a new UV bulb. Reach Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for assistance.
    • 210—Register online for outdoor temperature. Get 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 do this step and ensure proper 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. Use the Lyric app and follow the steps to connect your thermostat.

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

Our Experts are Available to Help

If you’re still experiencing troubles after trying the troubleshooting steps, our Experts are here to help. Reach us at 866-397-3787 and we’ll arrive rapidly to determine the issue.

If you use a dated thermostat, right now is a good time to think about a new device. Thermostat technology has come a long way in recent years Ask us for more information on how smart thermostats can make your home more comfortable while helping save on utility costs throughout the year.

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