How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the top thermostat manufacturers, and we proudly install them on a frequent basis in Sharonville. They’re durable and reliable. Plus, Honeywell is regularly advancing its technology, resulting in more features for your family.

Nevertheless, every thermostat can have issues now and then. That’s why we’ve prepared this informative handbook to run through troubleshooting.

While you can often repair the majority of thermostat troubles alone, they often call for Expert assistance. Our heating and cooling Experts are available to assist you when you need us. We’re just a call away at 859-905-0834.

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

What Model of Thermostat Do I Have?

There are three models of thermostats:

  • Manual—This is the classic dial-shaped thermostat. You won’t run into error codes with this type, but it’s also the least efficient for reducing heating and cooling bills.
  • Programmable—This thermostat features a digital screen and arrows you use to choose your desired temperature. You can also choose daily programs to decrease the temperature when you’re away and raise it when you get back.
  • Smart—You won’t have to make any programs on this thermostat, because it picks up on your schedule. It automatically adjusts the temperature when you or loved ones are gone to help you save on heating and cooling expenses. You can also change the temperature anywhere using your phone or other Wi-Fi-enabled device. 

As is the case with most technologically advanced things, there are common malfunctions that might happen. Most of these troubles don’t require Expert help and are simple to repair alone.

Common Honeywell Thermostat Troubles

Every thermostat has an exclusive kind of codes that correspond to the glitches that occur.

Think how easy it can be to restore a computer by restarting it. For the most part, troubleshooting a thermostat can be just as uncomplicated.

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

Display is Blank

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

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

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

A panel that isn’t tight may trigger the safety switch, which disconnects power to the system.

Less frequently, a blank monitor can mean you need to replace your thermostat.

Heating and Cooling Unit Won’t Start

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

When it’s hot, make sure you schedule the thermostat below the room temperature. When it’s cool, verify it’s higher. This sounds goofy, but we’ve seen it take place a lot of times.

Confirm the power switch near your indoor equipment is in the “on” position. You should also make sure the cabinet doors or panels are closed on your furnace cabinet or air handler. An unsecured panel can trip the safety switch, diverting power to the system.

Equipment still won’t turn on? Make sure circuit breakers haven’t turned off and that your HVAC equipment isn’t experiencing error codes.

“Cool On” or “Heat On” is Flashing

First, ensure your thermostat is set to “cool” or “heat.”

Then, check it’s signaling the right equipment to start. This is typically indicated by “cool on,” “heat on” or an illustration.

If this set of words or the icon is flashing, your thermostat is in a five-minute delay status. This feature keeps your system from bad short cycling. This could occur if your power is interrupted.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump requires service. Call Knochelmann Service Experts at 859-905-0834 for support.
  • 168—Wi-Fi radio error. Contact Lyric technical support at 800-633-3991. 170—Internal memory error. Reach Lyric technical support at 800-633-3991.
  • 171—Set date and time. Finish these settings so scheduling can run.
  • 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 thermostat by touching “dismiss” after putting in a new filter.
  • 184—Put in a new humidifier pad. Clear the monitor by tapping “dismiss” after putting in a clean pad filter.
  • 185—Replace dehumidifier filter. Clear the screen by touching “dismiss” after installing a new filter.
  • 187—Clean or replace ventilator filter. Clear the thermostat by touching “dismiss” after installing a clean filter.
  • 188/189—Install a new UV bulb. Contact Knochelmann Service Experts at 859-905-0834 for help.
  • 210—Register online for outside temperature. Download the Lyric app to finish this step and ensure proper thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Download 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 choose new Wi-Fi network.
  • 508—Wi-Fi not set up. Use the Lyric app and follow the steps to configure your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump must be serviced service. Reach Knochelmann Service Experts at 859-905-0834 for assistance.
  • 168—Wi-Fi radio error. Call Knochelmann Service Experts at 859-905-0834 for support.
  • 170—Internal memory error. Call Knochelmann Service Experts at 859-905-0834 for assistance.
  • 171—Set date and time. Finish these settings so scheduling can work.
  • 173—Thermostat temperature sensor error. Contact Knochelmann Service Experts at 859-905-0834 for support.
  • 175—AC power restored. No action necessary.
  • 177—Indoor temperature sensor error. Call Knochelmann Service Experts at 859-905-0834 for assistance.
  • 178—Outdoor temperature sensor error. Contact Knochelmann Service Experts at 859-905-0834 for help.
  • 181/182—Install a new air filter. Clear the thermostat by touching “dismiss” after putting in a new filter.
  • 183—Clean humidifier tank and install a new water filter. Clear the display by touching “dismiss” after doing these procedures.
  • 184—Get a new humidifier pad. Clear the thermostat by touching “dismiss” after installing pad filter.
  • 185—Get a new dehumidifier filter. Clear the monitor by tapping “dismiss” after installing a clean filter.
  • 186—Rinse ventilator core. Clear the display by touching “dismiss” after finishing this task.
  • 187—Rinse or replace ventilator filter. Clear the screen by tapping “dismiss” after getting a new filter.
  • 188/189—Add a new UV bulb. Get in touch with Knochelmann Service Experts at 859-905-0834 for help.
  • 210—Register online for outside temperature. Use the Lyric app to do this step and ensure accurate thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Use the Lyric app to complete 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 choose new Wi-Fi network.
  • 508—Wi-Fi not set up. Download the Lyric app and follow the process to connect your thermostat.

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

Our Experts are Here to Provide Assistance

If you’re still having problems after working through the troubleshooting steps, our pros are here to assist you. Give us a call at 859-905-0834 and we’ll be out as fast as we can to determine the issue.

If you use a dated thermostat, right now is a good time to think about a replacement. Thermostat technology has advanced over the last few years. Ask us for more details on how smart thermostats can make your house comfier while helping save on energy costs all year.

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