How to Troubleshoot Honeywell Thermostat Errors

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

Still, every thermostat can have issues now and then. That’s why we’ve compiled this useful guidebook to walk you through troubleshooting.

While you can usually repair most thermostat troubles on your own, they sometimes require Expert assistance. Our heating and cooling professionals are available to support you when you need us. We’re only a call away at 512-596-1257.

Let’s get started with the process by determining what kind of thermostat your residence has.

What Type of Thermostat Do I Have?

There are three models of thermostats:

  • Manual—This is the older dial-shaped thermostat. You won’t have error codes with this one, but it’s also the least efficient for reducing heating and cooling expenses.
  • Programmable—This thermostat has a digital screen and arrows you use to set your desired temperature. You can also set daily programs to lower the temperature when you’re gone and raise it when you come home.
  • Smart—You won’t have to set any programs on this thermostat, since it picks up on your day. It intuitively raises and lowers the temperature when you or family members are out and about to help you save on utility costs. You can also change the temperature anywhere on your phone or other Wi-Fi-enabled device. 

As is the case with the majority of technologically advanced things, there are several problems that may take place. Most of these issues don’t call for pro help and are simple to solve by yourself.

Common Honeywell Thermostat Problems

All thermostats have a special kind of codes matching the problems that happen.

Think how easy it can be to restore a computer by restarting it. In most cases, correcting a thermostat can be just as easy.

Here is a guide to 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 could need to get new batteries. If that doesn’t fix the issue or you have a smart thermostat, there may be a wiring issue.

Next, you should make sure the power is enabled for your furnace or air handler. Verify the switch by the indoor system is in the “on” position.

Also, you should confirm all furnace cabinet or air handler doors/panels are tightly secured.

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

While it’s less common, a clear monitor could signify you should get a new thermostat.

Comfort Equipment Won’t Turn On

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

During warm weather, confirm you set the thermostat lower than the room temperature. When it’s cool, verify it’s higher. This sounds goofy, but we’ve seen it take place many times.

Confirm the power switch close to your indoor system is in the “on” position. You should also make sure the cabinet doors or panels are tight on your furnace cabinet or air handler. A loose panel can trigger the safety switch, diverting current to the system.

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

“Cool On” or “Heat On” is Flickering

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

Then, check it’s calling for the appropriate unit to start. This is often indicated by “cool on,” “heat on” or a picture.

If this phrase or the icon is pulsing, your thermostat is in a five-minute delay state. This mode protects your unit from harmful short cycling. This could take place if you lose power.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump must be serviced. Call Strand Brothers Service Experts at 512-596-1257 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. 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 required.
  • 181/182—Replace air filter. Clear the thermostat by touching “dismiss” after adding a new filter.
  • 184—Install a new humidifier pad. Clear the display by touching “dismiss” after installing a fresh pad filter.
  • 185—Install a new dehumidifier filter. Clear the display by hitting “dismiss” after adding a fresh filter.
  • 187—Wash or install a new ventilator filter. Clear the thermostat by tapping “dismiss” after adding a clean filter.
  • 188/189—Get a new UV bulb. Contact Strand Brothers Service Experts at 512-596-1257 for assistance.
  • 210—Register online for exterior temperature. Get the Lyric app to finish this step and ensure correct thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Download the Lyric app to do this step and ensure correct 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 configured. Use the Lyric app and follow the process to connect your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump needs service. Reach Strand Brothers Service Experts at 512-596-1257 for support.
  • 168—Wi-Fi radio error. Reach Strand Brothers Service Experts at 512-596-1257 for help.
  • 170—Internal memory error. Call Strand Brothers Service Experts at 512-596-1257 for assistance.
  • 171—Set date and time. Finalize these settings so scheduling can operate.
  • 173—Thermostat temperature sensor error. Contact Strand Brothers Service Experts at 512-596-1257 for support.
  • 175—AC power reconnected. No action necessary.
  • 177—Indoor temperature sensor error. Call Strand Brothers Service Experts at 512-596-1257 for help.
  • 178—Outdoor temperature sensor error. Reach Strand Brothers Service Experts at 512-596-1257 for assistance.
  • 181/182—Install a new air filter. Clear the display by touching “dismiss” after installing a new filter.
  • 183—Wash humidifier tank and replace water filter. Clear the screen by hitting “dismiss” after doing these procedures.
  • 184—Replace humidifier pad. Clear the monitor by hitting “dismiss” after adding a new pad filter.
  • 185—Install a new dehumidifier filter. Clear the monitor by hitting “dismiss” after putting in a clean filter.
  • 186—Wash ventilator core. Clear the screen by touching “dismiss” after completing this task.
  • 187—Wash or get a new ventilator filter. Clear the screen by touching “dismiss” after buying a new filter.
  • 188/189—Install a new UV bulb. Contact Strand Brothers Service Experts at 512-596-1257 for support.
  • 210—Register online for outdoor temperature. Get the Lyric app to do this step and ensure correct thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Download 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 set up. Get the Lyric app and follow the steps to connect your thermostat.

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

Our Experts are Here to Help

If you’re still experiencing problems after trying the troubleshooting steps, our pros are here to support you. Reach us at 512-596-1257 and we’ll be out as fast as we can to figure out the malfunction.

If you rely on an aging thermostat, right now is a fantastic time to think about a replacement. 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 heating and cooling bills year-round.

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