How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the leading thermostat producers, and we proudly install them on a frequent basis in Buffalo. They’re durable and trustworthy. Plus, Honeywell is constantly updating its technology, resulting in more features for your house.

Still, every thermostat can run into troubles occasionally. As a result, we’ve put together this informative guide to run through troubleshooting.

While you can typically solve the majority of thermostat problems alone, they sometimes need Expert assistance. Our heating and cooling Experts are ready to support you when you need us. We’re merely a call away at 716-427-6807.

Let’s begin the process by finding 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 saving on heating and cooling bills.
  • Programmable—This thermostat features a digital screen and arrows you press to determine 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, as it picks up on your day. It automatically adjusts the temperature when you or loved ones are out and about to help you save on utility costs. You can also adjust the temperature anywhere via your phone or other Wi-Fi-enabled device. 

As is the case with the majority of technologically advanced products, there are regular malfunctions that can occur. Most of these situations don’t need Expert help and are easy to repair on your own.

Common Honeywell Thermostat Issues

Each thermostat has an exclusive set of codes assigned to the troubles that occur.

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

Here is a listing the most reported Honeywell thermostat errors. These include the following programmable thermostats:

Display is Blank

If the monitor is blank on your programmable thermostat, you may need to replace the batteries. If that doesn’t solve the issue or you use a smart thermostat, there could be a wiring malfunction.

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

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

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

Less frequently, an empty display may mean you will need to replace your thermostat.

Comfort Unit Won’t Start

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

In the summer, confirm you put the thermostat lower than the room temperature. When it’s cool, make sure it’s higher. This sounds absurd, but we’ve seen it occur a lot of times.

Ensure the power switch close to your indoor system is in the “on” position. You should also check the cabinet doors or panels are secure on your furnace cabinet or air handler. An unsecured panel can trip the safety switch, diverting power to the equipment.

Equipment still won’t start? Confirm circuit breakers haven’t turned off and that your HVAC equipment isn’t displaying error codes.

“Cool On” or “Heat On” is Flashing

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

Then, make sure it’s telling the right equipment to turn on. This is usually indicated by “cool on,” “heat on” or an illustration.

If this phrase or the picture is flashing, your thermostat is in a five-minute delay state. This setting keeps your unit from bad short cycling. This could occur if you lose power.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump requires service. Call Sunbeam Service Experts at 716-427-6807 for help.
  • 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. Finish these settings so scheduling can take place.
  • 173—Thermostat temperature sensor error. Reach Lyric technical support at 800-633-3991.
  • 175—AC power restarted. No action needed.
  • 181/182—Install a new air filter. Clear the monitor by touching “dismiss” after installing a new filter.
  • 184—Put in a new humidifier pad. Clear the display by tapping “dismiss” after putting in a new pad filter.
  • 185—Put in a new dehumidifier filter. Clear the screen by tapping “dismiss” after adding a fresh filter.
  • 187—Clean or put in a new ventilator filter. Clear the screen by touching “dismiss” after installing a new filter.
  • 188/189—Get a new UV bulb. Call Sunbeam Service Experts at 716-427-6807 for support.
  • 210—Register online for outdoor temperature. Use the Lyric app to do this step and ensure accurate thermostat operation.
  • 388—Register online for remote access and outside temperature. Use 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 select new Wi-Fi network.
  • 508—Wi-Fi not set up. Download the Lyric app and follow the process to configure 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. Reach Sunbeam Service Experts at 716-427-6807 for help.
  • 168—Wi-Fi radio error. Call Sunbeam Service Experts at 716-427-6807 for help.
  • 170—Internal memory error. Call Sunbeam Service Experts at 716-427-6807 for help.
  • 171—Set date and time. Finish these settings so scheduling can operate.
  • 173—Thermostat temperature sensor error. Reach Sunbeam Service Experts at 716-427-6807 for support.
  • 175—AC power resumed. No action required.
  • 177—Indoor temperature sensor error. Contact Sunbeam Service Experts at 716-427-6807 for assistance.
  • 178—Outdoor temperature sensor error. Call Sunbeam Service Experts at 716-427-6807 for support.
  • 181/182—Install a new air filter. Clear the screen by tapping “dismiss” after installing a clean filter.
  • 183—Clean humidifier tank and install a new water filter. Clear the thermostat by hitting “dismiss” after doing these procedures.
  • 184—Get a new humidifier pad. Clear the monitor by touching “dismiss” after installing pad filter.
  • 185—Get a new dehumidifier filter. Clear the screen by tapping “dismiss” after installing a new filter.
  • 186—Wash ventilator core. Clear the screen by hitting “dismiss” after finishing this task.
  • 187—Rinse or get a new ventilator filter. Clear the display by tapping “dismiss” after getting a new filter.
  • 188/189—Add a new UV bulb. Contact Sunbeam Service Experts at 716-427-6807 for help.
  • 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 accurate 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 configured. Download the Lyric app and follow the procedures to connect your thermostat.

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

Our Experts are Here to Provide Assistance

If you’re still having issues after going through the troubleshooting process, our Experts are here to support you. Reach us at 716-427-6807 and we’ll arrive rapidly to determine the problem.

If you have an older thermostat, right now is a great time to think about a new thermostat. Thermostat technology has gotten better in recent years Ask us for more info on how smart thermostats can make your home more comfortable while helping save on energy costs all year.

Contact Us