How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the best thermostat producers, and we proudly install them on a regular basis in Louisville. They’re long-lasting and reliable. Also, Honeywell is regularly improving its technology, bringing more features for your household.

Still, every thermostat can have troubles from time to time. Due to this, we’ve prepared this useful handbook to walk you through troubleshooting. While Honeywell thermostat problems are rare, they do occur. 

While you can typically fix most thermostat problems on your own, they often need Expert support. Our home comfort Experts are here to support you when you need us. We’re merely a call away at 502-785-8230.

Let’s begin the process by determining what model of thermostat your residence has.

What Kind of Thermostat Do I Have?

There are three types of thermostats:

  • Manual—This is the older dial-shaped thermostat. You won’t run into error codes with this type, but it’s also the least efficient for saving on heating and cooling bills.
  • Programmable—This thermostat includes a digital screen and arrows you use to set your desired temperature. You can also use daily programs to reduce the temperature when you’re gone and increase it when you return.
  • Smart—You won’t have to schedule any programs on this thermostat, because it learns your schedule. It intuitively raises and lowers the temperature when you or loved ones are gone to help you save on heating and cooling expenses. You can also adjust the temperature anywhere on your phone or other Wi-Fi-enabled device. 

As is the case with most technologically advanced solutions, there are common glitches that may take place. Many of these troubles don’t need pro support and are uncomplicated enough to fix by yourself.

Common Honeywell Thermostat Troubles

Every thermostat has an exclusive set of codes matching the problems that take place.

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

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

Display is Blank

If the screen is empty on your programmable thermostat, you could need to get new batteries. If that doesn’t solve the issue or you have a smart thermostat, there could be a wiring malfunction.

Next, you should ensure the power is on for your furnace or air handler. Make sure the switch by the indoor equipment is switched “on”.

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

A loose panel may trigger the safety switch, which stops power to the equipment.

Infrequently, a blank screen may indicate you need to buy a new thermostat.

HVAC Unit Won’t Turn On

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

During warm weather, verify you set the thermostat below the current temperature. When it’s cool, confirm it’s higher. This sounds absurd, but we’ve seen it take place a lot of times.

Make sure the power switch by 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 open panel can trip the safety switch, cutting off electricity to the unit.

Heating or cooling still won’t run? Confirm circuit breakers haven’t tripped and that your HVAC equipment isn’t experiencing error codes.

“Cool On” or “Heat On” is Blinking

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

Then, ensure it’s telling the right equipment to turn on. This is often demonstrated by “cool on,” “heat on” or an illustration.

If these words or the icon is flashing, your thermostat is in a five-minute delay mode. This feature stops your system from damaging 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 Becht/Givens Service Experts at 502-785-8230 for support.
  • 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. 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 hitting “dismiss” after putting in a fresh filter.
  • 184—Put in a new humidifier pad. Clear the thermostat by touching “dismiss” after installing a new pad filter.
  • 185—Install a new dehumidifier filter. Clear the monitor by hitting “dismiss” after adding a clean filter.
  • 187—Wash or put in a new ventilator filter. Clear the monitor by hitting “dismiss” after installing a clean filter.
  • 188/189—Replace UV bulb. Contact Becht/Givens Service Experts at 502-785-8230 for assistance.
  • 210—Register online for exterior temperature. Get the Lyric app to finish this step and ensure accurate thermostat operation.
  • 388—Register online for remote access and outdoor 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 select new Wi-Fi network.
  • 508—Wi-Fi not set. Get the Lyric app and follow the steps to connect your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump must be serviced service. Reach Becht/Givens Service Experts at 502-785-8230 for help.
  • 168—Wi-Fi radio error. Contact Becht/Givens Service Experts at 502-785-8230 for support.
  • 170—Internal memory error. Contact Becht/Givens Service Experts at 502-785-8230 for support.
  • 171—Set date and time. Finalize these settings so scheduling can work.
  • 173—Thermostat temperature sensor error. Call Becht/Givens Service Experts at 502-785-8230 for help.
  • 175—AC power restored. No action needed.
  • 177—Indoor temperature sensor error. Reach Becht/Givens Service Experts at 502-785-8230 for assistance.
  • 178—Outdoor temperature sensor error. Reach Becht/Givens Service Experts at 502-785-8230 for support.
  • 181/182—Get a new air filter. Clear the thermostat by tapping “dismiss” after installing a new filter.
  • 183—Clean humidifier tank and install a new water filter. Clear the thermostat by tapping “dismiss” after completing these steps.
  • 184—Get a new humidifier pad. Clear the monitor by touching “dismiss” after installing pad filter.
  • 185—Get a new dehumidifier filter. Clear the monitor by touching “dismiss” after installing a fresh filter.
  • 186—Clean ventilator core. Clear the monitor by tapping “dismiss” after completing this task.
  • 187—Clean or get a new ventilator filter. Clear the display by hitting “dismiss” after getting a new filter.
  • 188/189—Replace UV bulb. Reach Becht/Givens Service Experts at 502-785-8230 for help.
  • 210—Register online for exterior temperature. Download the Lyric app to finish this step and ensure accurate thermostat operation.
  • 388—Register online for remote access and outside temperature. Get the Lyric app to do 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 configured. Get 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 Help

If you’re still having issues after working through the troubleshooting list, our professionals are here to support you. Call us at 502-785-8230 and we’ll come to your house as fast as we can to determine the problem.

If you use an aging thermostat, right now is a great time to think about a new thermostat. Thermostat technology has gotten better over the last few years. Ask us for more info on how smart thermostats can make your house more convenient while helping save on heating and cooling costs year-round.

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