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 dependable. Also, Honeywell is regularly improving its technology, bringing more features for your household.

Nevertheless, every thermostat can have troubles from time to time. Due to this, we’ve prepared this useful handbook to walk you through troubleshooting.

While you can often fix most thermostat problems on your own, they often call for Expert help. Our HVAC professionals are available to support you when you need us. We’re just a call away at 502-785-8230.

Let’s begin the process by determining what model of thermostat your house 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 kind, but it’s also the least efficient for saving on heating and cooling bills.
  • Programmable—This thermostat features a digital screen and arrows you touch to set your desired temperature. You can also use daily programs to reduce the temperature when you’re gone and set it higher when you get back.
  • Smart—You won’t have to make any programs on this thermostat, because it learns your schedule. It intuitively changes the temperature when you or family members are gone to help you save on energy costs. You can also adjust 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 take place. Many of these issues don’t call for pro support and are uncomplicated enough to fix by yourself.

Common Honeywell Thermostat Issues

Every thermostat has an exclusive set of codes that correspond to 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 encountered Honeywell thermostat issues. These involve the following programmable thermostats:

Display is Blank

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

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

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

A loose panel may activate the safety switch, which disconnects power to the system.

Infrequently, a blank screen can signify you need to buy a new thermostat.

HVAC Equipment Won’t Turn On

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

When it’s hot, verify you set the thermostat below the current temperature. When it’s cold, confirm it’s higher. This sounds goofy, but we’ve seen it take place lots of times.

Make sure the power switch by your indoor equipment 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 current to the unit.

Heating or cooling still won’t start? Confirm circuit breakers haven’t tripped and that your HVAC unit isn’t showing error codes.

“Cool On” or “Heat On” is Flickering

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

Then, ensure it’s signaling the correct equipment to start. 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 setting keeps your system from damaging short cycling. This could take place 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 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. Reach Lyric technical support at 800-633-3991.
  • 175—AC power restarted. No action needed.
  • 181/182—Put in a new air filter. Clear the monitor by tapping “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 putting in a clean filter.
  • 187—Wash or install a new ventilator filter. Clear the screen 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 outside temperature. Get the Lyric app to finish this step and ensure accurate thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Get the Lyric app to do 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. Contact Becht/Givens Service Experts at 502-785-8230 for support.
  • 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 help.
  • 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. Contact 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 add a new water filter. Clear the thermostat by hitting “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 clean filter.
  • 186—Clean ventilator core. Clear the monitor by hitting “dismiss” after finishing this task.
  • 187—Clean or get a new ventilator filter. Clear the monitor by hitting “dismiss” after buying a new filter.
  • 188/189—Get a new UV bulb. Reach Becht/Givens Service Experts at 502-785-8230 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 exterior temperature. Get the Lyric app to finish 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. Reach 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, today is a great time to think over a new device. Thermostat technology has gotten better over the last few years. Ask us for more info on how smart thermostats can make your residence more convenient while helping save on heating and cooling expenses year-round.

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