How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the leading thermostat producers, and we proudly install them on a frequent basis in Austin. They’re long-lasting and reliable. Plus, Honeywell is frequently enhancing its technology, resulting in more features for your household.

However, each thermostat can experience troubles at one time or another. As a result, we’ve put together this valuable guidebook to go over troubleshooting.

While you can often repair many thermostat troubles by yourself, they often call for Expert help. Our heating and cooling pros are available to support you when you need us. We’re only a call away at 512-592-3072 .

Let’s start the process by determining what kind of thermostat your residence 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 run into error codes with this one, but it’s also the least efficient for lowering utility expenses.
  • Programmable—This thermostat features a digital screen and arrows you use to determine your desired temperature. You can also choose daily programs to decrease the temperature when you’re gone and set it higher when you return.
  • Smart—You won’t have to make any programs on this thermostat, as it picks up on your routine. It intuitively changes the temperature when you or loved ones are away to help you save on heating and cooling expenses. You can also change the temperature anywhere on your phone or other Wi-Fi-enabled device. 

As you know most technologically advanced things, there are several glitches that may take place. Most of these troubles don’t require Expert support and are easy to repair alone.

Common Honeywell Thermostat Troubles

All thermostats have a unique group of codes that correspond to the malfunctions that happen.

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

Here are some of the most reported Honeywell thermostat problems. These include the following programmable thermostats:

Display is Blank

If the screen is clear on your programmable thermostat, you might need to put in new batteries. If that doesn’t take care of the malfunction or you rely on a smart thermostat, there might be a wiring problem.

Next, you should make sure the power is flowing for your furnace or air handler. Confirm the switch close to the indoor system is switched “up”.

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

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

While it’s less common, a blank monitor could signify you will need to buy a new thermostat.

Heating and Cooling System Won’t Start

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

In the summer, make sure you schedule the thermostat below the room temperature. In the winter, verify it’s higher. This sounds goofy, but we’ve seen it happen many times.

Ensure the power switch near your indoor system is in the “on” position. You should also make sure 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.

Heating or cooling still won’t run? Make sure circuit breakers haven’t flipped and that your HVAC unit isn’t displaying error codes.

“Cool On” or “Heat On” is Flashing

To begin, ensure your thermostat is on “cool” or “heat.”

Then, make sure it’s signaling the right equipment to run. This is often demonstrated by “cool on,” “heat on” or an icon.

If this phrase or the icon is pulsing, your thermostat is in a five-minute delay status. This feature protects your system from harmful short cycling. This could occur if you lose electricity.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump needs service. Call Strand Brothers Service Experts at 512-592-3072 for help.
  • 168—Wi-Fi radio error. Call Lyric technical support at 800-633-3991. 170—Internal memory error. Contact Lyric technical support at 800-633-3991.
  • 171—Set date and time. Finalize these settings so scheduling can take place.
  • 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 touching “dismiss” after installing a clean filter.
  • 184—Put in a new humidifier pad. Clear the screen by hitting “dismiss” after installing a clean pad filter.
  • 185—Replace dehumidifier filter. Clear the screen by hitting “dismiss” after putting in a clean filter.
  • 187—Clean or replace ventilator filter. Clear the thermostat by hitting “dismiss” after installing a clean filter.
  • 188/189—Install a new UV bulb. Call Strand Brothers Service Experts at 512-592-3072 for support.
  • 210—Register online for outside temperature. Download the Lyric app to do this step and ensure correct thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Get the Lyric app to complete 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 select 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, look at this thermostat’s user manual.

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump must be serviced service. Contact Strand Brothers Service Experts at 512-592-3072 for support.
  • 168—Wi-Fi radio error. Call Strand Brothers Service Experts at 512-592-3072 for support.
  • 170—Internal memory error. Contact Strand Brothers Service Experts at 512-592-3072 for help.
  • 171—Set date and time. Finish these settings so scheduling can run.
  • 173—Thermostat temperature sensor error. Call Strand Brothers Service Experts at 512-592-3072 for assistance.
  • 175—AC power restored. No action needed.
  • 177—Indoor temperature sensor error. Contact Strand Brothers Service Experts at 512-592-3072 for assistance.
  • 178—Outdoor temperature sensor error. Contact Strand Brothers Service Experts at 512-592-3072 for help.
  • 181/182—Get a new air filter. Clear the monitor by touching “dismiss” after putting in a fresh filter.
  • 183—Clean humidifier tank and install a new water filter. Clear the screen by tapping “dismiss” after finishing these procedures.
  • 184—Get a new humidifier pad. Clear the display by touching “dismiss” after getting a new pad filter.
  • 185—Install a new dehumidifier filter. Clear the screen by touching “dismiss” after putting in a clean filter.
  • 186—Wash ventilator core. Clear the screen by touching “dismiss” after doing this task.
  • 187—Clean or get a new ventilator filter. Clear the monitor by touching “dismiss” after getting a new filter.
  • 188/189—Get a new UV bulb. Reach Strand Brothers Service Experts at 512-592-3072 for support.
  • 210—Register online for outdoor temperature. Use the Lyric app to do this step and ensure proper thermostat operation.
  • 388—Register online for remote access and outdoor 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 select new Wi-Fi network.
  • 508—Wi-Fi not connected. Get the Lyric app and follow the procedures to connect your thermostat.

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

Our Experts are Available to Provide Support

If you’re still having troubles after going through the troubleshooting list, our pros are ready to support you. Call us at 512-592-3072 and we’ll be out as fast as we can to determine the problem.

If you use a dated thermostat, right now is a good time to consider a replacement. Thermostat technology has gotten better over the last few years. Ask us for more info on how smart thermostats can make your residence comfier while helping save on heating and cooling bills year-round.

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