How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the best thermostat brands, and we proudly install them on a regular basis in Long Island. They’re long-lasting and dependable. Also, Honeywell is constantly updating its technology, offering more features for your house.

However, each thermostat can run into errors from time to time. That’s why we’ve compiled this useful manual to go over troubleshooting. While Honeywell thermostat troubleshooting problems are rare, they do occur.

While you can usually repair the majority of thermostat problems alone, they often need Expert assistance. Our heating and cooling pros are available to assist you when you need us. We’re only a call away at 631-406-9220.

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

What Kind of Thermostat Do I Have?

There are three kinds of thermostats:

Manual—This is the typical dial-shaped thermostat. You won’t experience error codes with this one, but it’s also the least efficient for lowering energy bills.
Programmable—This thermostat includes a digital screen and arrows you use to determine your desired temperature. You can also choose daily programs to lower the temperature when you’re gone and set it higher when you return.
Smart—You won’t have to schedule any programs on this thermostat, since it picks up on your routine. It instinctively raises and lowers the temperature when you or loved ones are out and about to help you save on heating and cooling expenses. You can also raise or lower the temperature anywhere using your phone or other Wi-Fi-enabled device.

As is the case with most technologically advanced products, there are regular glitches that can happen. Many of these issues don’t require Expert help and are simple to solve alone.

Common Honeywell Thermostat Troubleshooting Errors

Each Honeywell thermostat has a special set of codes that correspond to the malfunctions that occur.

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

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

Display is Blank

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

Next, you should ensure the power is on for your furnace or air handler. Verify the switch near the indoor equipment is in the “on” position.

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

A panel that isn’t tight may trip the safety switch, which stops power to the equipment.

Less frequently, a clear screen can mean you will need to install a new thermostat.

Heating and Cooling Unit Won’t Turn On

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

In the summer, verify you put the thermostat below the current temperature. In the winter, verify it’s higher. This sounds silly, but we’ve seen it happen a lot of times.

Ensure the power switch by your indoor unit is in the “on” position. You should also make sure the cabinet doors or panels are tight on your furnace cabinet or air handler. An open panel can activate the safety switch, cutting off electricity to the unit.

Unit still won’t turn on? Verify circuit breakers haven’t tripped and that your HVAC system isn’t showing error codes.

“Cool On” or “Heat On” is Blinking

To start, make sure 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 these words or the picture is pulsing, your thermostat is in a five-minute delay state. This setting stops your equipment from harmful 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 Matz-Rightway at 631-406-9220 for help.
168—Wi-Fi radio error. Reach Lyric technical support at 800-633-3991. 170—Internal memory error. Reach Lyric technical support at 800-633-3991.
171—Set date and time. Finalize these settings so scheduling can run.
173—Thermostat temperature sensor error. Contact 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 tapping “dismiss” after putting in a clean filter.
184—Replace humidifier pad. Clear the monitor by touching “dismiss” after installing a new pad filter.
185—Replace dehumidifier filter. Clear the screen by touching “dismiss” after installing a clean filter.
187—Clean or install a new ventilator filter. Clear the monitor by touching “dismiss” after installing a fresh filter.
188/189—Replace UV bulb. Call Matz-Rightway at 631-406-9220 for assistance.
210—Register online for outside temperature. Get the Lyric app to finish this step and ensure proper thermostat operation.
388—Register online for remote access and exterior temperature. Get 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 select new Wi-Fi network.
508—Wi-Fi not configured. Download the Lyric app and follow the steps to link your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005)

164—Heat pump must be serviced service. Call Matz-Rightway at 631-406-9220 for support.
168—Wi-Fi radio error. Reach Matz-Rightway at 631-406-9220 for assistance.
170—Internal memory error. Contact Matz-Rightway at 631-406-9220 for help.
171—Set date and time. Complete these settings so scheduling can run.
173—Thermostat temperature sensor error. Reach Matz-Rightway at 631-406-9220 for help.
175—AC power resumed. No action necessary.
177—Indoor temperature sensor error. Contact Matz-Rightway at 631-406-9220 for help.
178—Outdoor temperature sensor error. Reach Matz-Rightway at 631-406-9220 for help.
181/182—Install a new air filter. Clear the thermostat by touching “dismiss” after putting in a new filter.
183—Rinse humidifier tank and replace water filter. Clear the screen by touching “dismiss” after finishing these tasks.
184—Get a new humidifier pad. Clear the monitor by tapping “dismiss” after installing pad filter.
185—Get a new dehumidifier filter. Clear the screen by tapping “dismiss” after installing a fresh filter.
186—Wash ventilator core. Clear the thermostat by tapping “dismiss” after completing this task.
187—Wash or replace ventilator filter. Clear the display by tapping “dismiss” after getting a new filter.
188/189—Replace UV bulb. Get in touch with Matz-Rightway at 631-406-9220 for help.
210—Register online for outside temperature. Download the Lyric app to do this step and ensure accurate thermostat operation.
388—Register online for remote access and outside temperature. Get the Lyric app to finish 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 pick new Wi-Fi network.
508—Wi-Fi not configured. 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 Provide Support

If you’re still experiencing problems after going through the troubleshooting list, our Experts are ready to support you. Call us at 631-406-9220 and we’ll arrive quickly to determine the issue.

If you use an aging thermostat, right now is a great time to consider a new device. Thermostat technology has advanced over the last few years. Ask us for more details on how smart thermostats can make your house better while helping save on heating and cooling costs all year.