How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the leading thermostat brands, and we proudly install them on a frequent basis in Boise. They’re sturdy and reliable. Plus, Honeywell is regularly updating its technology, resulting in more features for your family.

Nevertheless, all thermostats can have errors every now and then. Due to this, we’ve prepared this useful manual to walk you through troubleshooting.

While you can usually fix most thermostat troubles by yourself, they often need Expert help. Our HVAC Experts are ready to help when you need us. We’re just a call away at 208-488-4892.

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

What Model of Thermostat Do I Have?

There are three types of thermostats:

  • Manual—This is the typical 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 features a digital screen and arrows you touch to determine your desired temperature. You can also use daily programs to reduce the temperature when you’re gone and raise it when you return.
  • Smart—You won’t have to schedule any programs on this thermostat, because it learns your schedule. It instinctively adjusts the temperature when you or family members are away to help you save on heating and cooling costs. You can also raise or lower the temperature anywhere via your phone or other Wi-Fi-enabled device. 

As you’re aware the majority of technologically advanced products, there are common glitches that may take place. The majority of of these issues don’t call for pro support and are simple to repair alone.

Common Honeywell Thermostat Troubles

Every thermostat has a special set of codes assigned to the malfunctions that occur.

Think how uncomplicated it can be to fix a computer by restarting it. In most situations, correcting a thermostat can be just as simple.

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

Display is Blank

If the screen is blank on your programmable thermostat, you might need to install new batteries. If that doesn’t take care of the trouble or you have a smart thermostat, there may be a wiring problem.

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

Also, you should make certain all furnace cabinet or air handler doors/panels are securely fastened.

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

Less frequently, a blank display could indicate you will need to install a new thermostat.

HVAC Equipment Won’t Turn On

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

During warm weather, make sure you put the thermostat lower than the room temperature. In the winter, verify it’s higher. This sounds absurd, but we’ve seen it occur a lot of times.

Make sure the power switch near your indoor unit is in the “on” position. You should also comfirm the cabinet doors or panels are secure on your furnace cabinet or air handler. An unsecured panel can trigger the safety switch, cutting off current to the system.

Unit still won’t turn on? Verify circuit breakers haven’t tripped and that your HVAC equipment isn’t experiencing error codes.

“Cool On” or “Heat On” is Blinking

To begin, make sure your thermostat is set to “cool” or “heat.”

Then, make sure it’s calling for the right unit to start. This is typically shown by “cool on,” “heat on” or a picture.

If this set of words or the illustration is blinking, your thermostat is in a five-minute delay state. This feature stops your equipment from damaging short cycling. This could occur if you lose power.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump needs service. Call TML Service Experts at 208-488-4892 for assistance.
  • 168—Wi-Fi radio error. Call Lyric technical support at 800-633-3991. 170—Internal memory error. Call Lyric technical support at 800-633-3991.
  • 171—Set date and time. Finalize these settings so scheduling can occur.
  • 173—Thermostat temperature sensor error. Contact Lyric technical support at 800-633-3991.
  • 175—AC power restarted. No action needed.
  • 181/182—Replace air filter. Clear the screen by touching “dismiss” after adding a new filter.
  • 184—Put in a new humidifier pad. Clear the monitor by hitting “dismiss” after adding a fresh pad filter.
  • 185—Put in a new dehumidifier filter. Clear the thermostat by hitting “dismiss” after adding a clean filter.
  • 187—Wash or install a new ventilator filter. Clear the thermostat by hitting “dismiss” after putting in a fresh filter.
  • 188/189—Get a new UV bulb. Call TML Service Experts at 208-488-4892 for help.
  • 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 outside temperature. Use the Lyric app to do 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 pick new Wi-Fi network.
  • 508—Wi-Fi not set. Use the Lyric app and follow the process to link your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump requires service. Contact TML Service Experts at 208-488-4892 for help.
  • 168—Wi-Fi radio error. Call TML Service Experts at 208-488-4892 for support.
  • 170—Internal memory error. Contact TML Service Experts at 208-488-4892 for assistance.
  • 171—Set date and time. Finalize these settings so scheduling can work.
  • 173—Thermostat temperature sensor error. Reach TML Service Experts at 208-488-4892 for help.
  • 175—AC power reconnected. No action required.
  • 177—Indoor temperature sensor error. Reach TML Service Experts at 208-488-4892 for support.
  • 178—Outdoor temperature sensor error. Call TML Service Experts at 208-488-4892 for support.
  • 181/182—Replace air filter. Clear the display by tapping “dismiss” after installing a clean filter.
  • 183—Clean humidifier tank and add a new water filter. Clear the thermostat by touching “dismiss” after doing these tasks.
  • 184—Install a new humidifier pad. Clear the thermostat by touching “dismiss” after installing pad filter.
  • 185—Get a new dehumidifier filter. Clear the thermostat by tapping “dismiss” after adding a new filter.
  • 186—Clean ventilator core. Clear the monitor by hitting “dismiss” after doing this task.
  • 187—Rinse or get a new ventilator filter. Clear the display by tapping “dismiss” after buying a new filter.
  • 188/189—Get a new UV bulb. Get in touch with TML Service Experts at 208-488-4892 for support.
  • 210—Register online for exterior temperature. Download the Lyric app to complete 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 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 configured. Download the Lyric app and follow the process to connect your thermostat.

For more details, see this thermostat’s user manual.

Our Experts are Here to Help

If you’re still having problems after going through the troubleshooting process, our pros are ready to support you. Call us at 208-488-4892 and we’ll be out quickly to determine the problem.

If you use an older thermostat, today is a good time to consider a new device. Thermostat technology has come a long way lately Ask us for more details on how smart thermostats can make your residence comfier while helping save on heating and cooling expenses all year.

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