How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the best thermostat producers, and we proudly install them on a regular basis in Calgary. They’re durable and reliable. In addition, Honeywell is regularly advancing its technology, bringing more features for your household.

Nevertheless, every thermostat can experience troubles every now and then. Due to this, we’ve prepared this valuable handbook to run through troubleshooting. While Honeywell thermostat troubleshooting problems are rare, they happen.

While you can often fix many thermostat issues by yourself, they often require Expert help. Our home comfort pros are here to assist you when you need us. We’re only a call away at 403-279-5760.

Let’s get started with the process by figuring out what kind of thermostat your home 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 run into error codes with this kind, but it’s also the least efficient for lowering heating and cooling bills.
Programmable—This thermostat has a digital screen and arrows you touch to choose your desired temperature. You can also use daily programs to reduce the temperature when you’re at work and raise it when you come home.
Smart—You won’t have to schedule any programs on this thermostat, as it learns your routine. It automatically adjusts the temperature when you or loved ones are gone to help you save on utility expenses. You can also adjust the temperature anywhere using your phone or other Wi-Fi-enabled device.

As you know most technologically advanced solutions, there are common problems that might happen. Most of these problems don’t require professional support and are easy to repair by yourself.

Common Honeywell Thermostat Troubleshooting Errors

Each Honeywell thermostat has a unique group of codes matching the issues that occur.

Think how simple it can be to repair a computer by restarting it. For the most part, diagnosing a thermostat can be just as easy.

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

Display is Blank

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

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

In addition to that, you should confirm all furnace cabinet or air handler doors/panels are securely fastened.

An unsecured panel may activate the safety switch, which disconnects power to the equipment.

While it’s less common, a clear screen could mean you should install a new thermostat.

HVAC Unit Won’t Turn On

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

When it’s hot, verify you schedule the thermostat beneath the room temperature. In the winter, confirm it’s higher. This sounds absurd, but we’ve seen it happen a lot of times.

Confirm the power switch close to your indoor equipment 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 activate the safety switch, diverting electricity to the equipment.

Unit still won’t start? Confirm circuit breakers haven’t tripped and that your HVAC system isn’t experiencing error codes.

“Cool On” or “Heat On” is Flashing

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

Then, verify it’s calling for the right unit to start. This is typically indicated by “cool on,” “heat on” or an icon.

If these words or the illustration is flashing, your thermostat is in a five-minute delay mode. This setting stops your equipment from bad short cycling. This may occur if you lose electricity.

Honeywell Thermostat-Specific Error Codes

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

164—Heat pump needs service. Call Service Experts Heating & Air Conditioning at 403-279-5760 for help.
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. Reach Lyric technical support at 800-633-3991.
175—AC power restarted. No action required.
181/182—Put in a new air filter. Clear the thermostat by touching “dismiss” after adding a new filter.
184—Put in a new humidifier pad. Clear the screen by touching “dismiss” after installing a clean pad filter.
185—Install a new dehumidifier filter. Clear the screen by hitting “dismiss” after installing a new filter.
187—Wash or put in a new ventilator filter. Clear the thermostat by tapping “dismiss” after installing a fresh filter.
188/189—Install a new UV bulb. Ring Service Experts Heating & Air Conditioning at 403-279-5760 for assistance.
210—Register online for outdoor temperature. Download the Lyric app to complete this step and ensure proper thermostat operation.
388—Register online for remote access and outside temperature. Use the Lyric app to finish 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 choose new Wi-Fi network.
508—Wi-Fi not set. Get the Lyric app and follow the steps to configure your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005)

164—Heat pump requires service. Call Service Experts Heating & Air Conditioning at 403-279-5760 for help.
168—Wi-Fi radio error. Reach Service Experts Heating & Air Conditioning at 403-279-5760 for support.
170—Internal memory error. Reach Service Experts Heating & Air Conditioning at 403-279-5760 for support.
171—Set date and time. Finish these settings so scheduling can work.
173—Thermostat temperature sensor error. Contact Service Experts Heating & Air Conditioning at 403-279-5760 for support.
175—AC power resumed. No action necessary.
177—Indoor temperature sensor error. Call Service Experts Heating & Air Conditioning at 403-279-5760 for support.
178—Outdoor temperature sensor error. Reach Service Experts Heating & Air Conditioning at 403-279-5760 for help.
181/182—Install a new air filter. Clear the display by touching “dismiss” after putting in a fresh filter.
183—Rinse humidifier tank and install a new water filter. Clear the display by tapping “dismiss” after completing these steps.
184—Get a new humidifier pad. Clear the thermostat by hitting “dismiss” after installing pad filter.
185—Replace dehumidifier filter. Clear the thermostat by tapping “dismiss” after installing a clean filter.
186—Rinse ventilator core. Clear the screen by hitting “dismiss” after completing this task.
187—Wash or get a new ventilator filter. Clear the display by hitting “dismiss” after buying a new filter.
188/189—Install a new UV bulb. Contact Service Experts Heating & Air Conditioning at 403-279-5760 for assistance.
210—Register online for exterior temperature. Download the Lyric app to complete this step and ensure proper thermostat operation.
388—Register online for remote access and exterior temperature. Use the Lyric app to finish this step and ensure proper 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 connected. Download the Lyric app and follow the process to connect your thermostat.

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

Our Experts are Ready to Provide Assistance

If you’re still running into issues after trying the troubleshooting list, our professionals are here to assist you. Give us a call at 403-279-5760 and we’ll come to your house quickly to figure out the problem.

If you rely on a dated thermostat, right now is a fantastic time to think about a new device. Thermostat technology has come a long way in recent years Ask us for more info on how smart thermostats can make your home more convenient while helping save on utility expenses year-round.

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