How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the leading thermostat producers, and we proudly install them on a usual basis in the U.S.. They’re long-lasting and trustworthy. Also, Honeywell is regularly advancing its technology, bringing more features for your residence.

Still, each thermostat can have troubles from time to time. Due to this, we’ve put together this useful manual to go over troubleshooting. While Honeywell thermostat troubleshooting problems are rare, they do occur.

While you can often repair most thermostat issues alone, they occasionally need Expert support. 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 get started with the process by determining what model of thermostat your house has.

What Kind of Thermostat Do I Have?

There are three types of thermostats:

    • Manual—This is the classic dial-shaped thermostat. You won’t experience error codes with this type, but it’s also the least efficient for saving on heating and cooling bills.
    • Programmable—This thermostat has a digital screen and arrows you press to determine your desired temperature. You can also choose daily programs to reduce the temperature when you’re away and raise it when you get back.
    • Smart—You won’t have to set any programs on this thermostat, because it learns your day. It instinctively raises and lowers the temperature when you or loved ones are out and about to help you save on heating and cooling bills. You can also adjust the temperature anywhere on your phone or other Wi-Fi-enabled device.

As you’re aware many technologically advanced products, there are regular malfunctions that can occur. Many of these situations don’t require Expert assistance and are simple to repair alone.

Common Honeywell Thermostat Troubleshooting Issues

All Honeywell thermostats have an exclusive kind of codes assigned to the troubles that occur.

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

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

Display is Blank

If the screen is clear on your programmable thermostat, you could need to get new batteries. If that doesn’t solve the problem or you use a smart thermostat, there might be a wiring issue.

Next, you should make sure the power is enabled for your furnace or air handler. Confirm the switch by the indoor unit is switched “up”.

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

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

Less frequently, a blank display might signify you should get a new thermostat.

Heating and Cooling Equipment Won’t Work

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

During warm weather, make sure you schedule the thermostat beneath the room temperature. When it’s cold, confirm it’s higher. This sounds goofy, but we’ve seen it occur a lot of times.

Make sure the power switch near 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. An unsecured panel can trip the safety switch, stopping electricity to the equipment.

Unit still won’t start? Make sure circuit breakers haven’t flipped and that your HVAC equipment isn’t displaying error codes.

“Cool On” or “Heat On” is Flickering

To begin, confirm your thermostat is switched to “cool” or “heat.”

Then, verify it’s signaling the right system to run. This is typically demonstrated by “cool on,” “heat on” or an icon.

If this set of words or the picture is pulsing, your thermostat is in a five-minute delay mode. This mode keeps your unit from damaging short cycling. This can happen if your power is interrupted.

Honeywell Thermostat-Specific Error Codes

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

    • 164—Heat pump must be serviced. 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. Finish these settings so scheduling can take place.
    • 173—Thermostat temperature sensor error. Contact Lyric technical support at 800-633-3991.
    • 175—AC power restarted. No action necessary.
    • 181/182—Put in a new air filter. Clear the display by touching “dismiss” after installing a fresh filter.
    • 184—Replace humidifier pad. Clear the display by hitting “dismiss” after putting in a new pad filter.
    • 185—Put in a new dehumidifier filter. Clear the display by tapping “dismiss” after installing a clean filter.
    • 187—Wash or put in a new ventilator filter. Clear the monitor by touching “dismiss” after installing a clean 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 outside temperature. Download the Lyric app to complete this step and ensure correct thermostat operation.
    • 388—Register online for remote access and exterior temperature. Use the Lyric app to do 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 select new Wi-Fi network.
    • 508—Wi-Fi not set up. Use the Lyric app and follow the procedure to link your thermostat.

For more information, view 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 assistance.
    • 168—Wi-Fi radio error. Reach 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 help.
    • 171—Set date and time. Finalize these settings so scheduling can run.
    • 173—Thermostat temperature sensor error. Reach Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for help.
    • 175—AC power resumed. No action necessary.
    • 177—Indoor temperature sensor error. Contact Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for assistance.
    • 178—Outdoor temperature sensor error. Reach Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for support.
    • 181/182—Replace air filter. Clear the monitor by hitting “dismiss” after adding a clean filter.
    • 183—Clean humidifier tank and install a new water filter. Clear the thermostat by hitting “dismiss” after finishing these steps.
    • 184—Replace humidifier pad. Clear the display by hitting “dismiss” after getting a new pad filter.
    • 185—Get a new dehumidifier filter. Clear the monitor by hitting “dismiss” after putting in a new filter.
    • 186—Wash ventilator core. Clear the monitor by hitting “dismiss” after doing this task.
    • 187—Rinse or replace ventilator filter. Clear the display by hitting “dismiss” after installing a new filter.
    • 188/189—Add a new UV bulb. Get in touch with Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 for help.
    • 210—Register online for outdoor temperature. Get the Lyric app to do this step and ensure proper thermostat operation.
    • 388—Register online for remote access and exterior temperature. Use the Lyric app to do 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 pick new Wi-Fi network.
    • 508—Wi-Fi not set up. Download the Lyric app and follow the steps to connect your thermostat.

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

Our Experts are Here to Provide Support

If you’re still experiencing issues after working through the troubleshooting process, our Experts are available to assist you. Give us a call at 866-397-3787 and we’ll arrive rapidly to figure out the problem.

If you rely on an aging thermostat, right now is a great time to consider a new thermostat. Thermostat technology has come a long way in recent years Ask us for more info on how smart thermostats can make your residence more convenient while helping save on utility expenses all year.

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