How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the top thermostat brands, and we proudly install them on a regular basis in Miami. They’re sturdy and reliable. Also, Honeywell is regularly improving its technology, offering more features for your household.

Nevertheless, every thermostat can have issues every so often. Due to this, we’ve prepared this useful guide to walk you through troubleshooting.

While you can typically fix most thermostat issues alone, they occasionally require Expert help. Our home comfort pros are ready to support you when you need us. We’re merely a call away at 305-440-1505.

Let’s get started with the process by figuring out what type of thermostat your house has.

What Kind of Thermostat Do I Have?

There are three models of thermostats:

  • Manual—This is the classic dial-shaped thermostat. You won’t experience error codes with this one, but it’s also the least efficient for lowering utility costs.
  • Programmable—This thermostat includes a digital screen and arrows you press to determine your desired temperature. You can also use daily programs to decrease the temperature when you’re at work and set it higher when you come home.
  • Smart—You won’t have to make any programs on this thermostat, as it adjusts to your schedule. It intuitively changes the temperature when you or loved ones are out and about to help you save on utility bills. You can also change the temperature anywhere on your phone or other Wi-Fi-enabled device. 

As is the case with most technologically advanced solutions, there are regular malfunctions that may take place. Most of these situations don’t need pro assistance and are simple to solve alone.

Common Honeywell Thermostat Troubles

Each thermostat has a special kind of codes matching the problems that take place.

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

Here is a listing the most reported Honeywell thermostat errors. These are applicable to the following programmable thermostats:

Display is Blank

If the display is blank on your programmable thermostat, you might need to replace the batteries. If that doesn’t fix the problem or you use a smart thermostat, there might be a wiring issue.

Next, you should make sure the power is flowing for your furnace or air handler. Verify the switch by the indoor unit is switched “on”.

In addition to that, you should confirm all furnace cabinet or air handler doors/panels are tightly fastened.

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

Less frequently, a blank display can signify you should buy a new thermostat.

Heating and Cooling Equipment Won’t Start

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

When it’s hot, confirm you put the thermostat beneath the current temperature. When it’s cool, verify it’s higher. This sounds silly, but we’ve seen it happen lots of times.

Confirm 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 open panel can trip the safety switch, stopping electricity to the equipment.

System still won’t start? Verify circuit breakers haven’t turned off and that your HVAC system isn’t experiencing error codes.

“Cool On” or “Heat On” is Flickering

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

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

If these words or the picture is pulsing, your thermostat is in a five-minute delay state. This setting keeps your equipment from bad 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 requires service. Call Service Experts Heating & Air Conditioning at 305-440-1505 for help.
  • 168—Wi-Fi radio error. Contact Lyric technical support at 800-633-3991. 170—Internal memory error. Contact 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. Call Lyric technical support at 800-633-3991.
  • 175—AC power restored. No action necessary.
  • 181/182—Install a new air filter. Clear the monitor by hitting “dismiss” after installing a fresh filter.
  • 184—Replace humidifier pad. Clear the monitor by tapping “dismiss” after installing a fresh pad filter.
  • 185—Install a new dehumidifier filter. Clear the thermostat by tapping “dismiss” after installing a fresh filter.
  • 187—Rinse or replace ventilator filter. Clear the monitor by tapping “dismiss” after installing a fresh filter.
  • 188/189—Replace UV bulb. Call Service Experts Heating & Air Conditioning at 305-440-1505 for support.
  • 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 outside 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 pick new Wi-Fi network.
  • 508—Wi-Fi not set up. Use the Lyric app and follow the process to link your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump must be serviced service. Call Service Experts Heating & Air Conditioning at 305-440-1505 for assistance.
  • 168—Wi-Fi radio error. Reach Service Experts Heating & Air Conditioning at 305-440-1505 for support.
  • 170—Internal memory error. Contact Service Experts Heating & Air Conditioning at 305-440-1505 for help.
  • 171—Set date and time. Complete these settings so scheduling can run.
  • 173—Thermostat temperature sensor error. Contact Service Experts Heating & Air Conditioning at 305-440-1505 for assistance.
  • 175—AC power restored. No action necessary.
  • 177—Indoor temperature sensor error. Reach Service Experts Heating & Air Conditioning at 305-440-1505 for support.
  • 178—Outdoor temperature sensor error. Call Service Experts Heating & Air Conditioning at 305-440-1505 for assistance.
  • 181/182—Get a new air filter. Clear the display by tapping “dismiss” after putting in a fresh filter.
  • 183—Clean humidifier tank and replace water filter. Clear the thermostat by tapping “dismiss” after completing these steps.
  • 184—Install a new humidifier pad. Clear the screen by hitting “dismiss” after installing pad filter.
  • 185—Replace dehumidifier filter. Clear the display by hitting “dismiss” after adding a fresh filter.
  • 186—Wash ventilator core. Clear the monitor by tapping “dismiss” after finishing this task.
  • 187—Wash or install a new ventilator filter. Clear the monitor by hitting “dismiss” after installing a new filter.
  • 188/189—Replace UV bulb. Contact Service Experts Heating & Air Conditioning at 305-440-1505 for help.
  • 210—Register online for exterior temperature. Use the Lyric app to do this step and ensure proper thermostat operation.
  • 388—Register online for remote access and exterior 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 pick new Wi-Fi network.
  • 508—Wi-Fi not set up. Use the Lyric app and follow the procedures to connect your thermostat.

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

Our Experts are Ready to Provide Assistance

If you’re still experiencing troubles after trying the troubleshooting steps, our Experts are ready to support you. Call us at 305-440-1505 and we’ll arrive rapidly to diagnose the malfunction.

If you rely on an aging thermostat, today is a fantastic time to think about a replacement. Thermostat technology has advanced in recent years Ask us for more information on how smart thermostats can make your home better while helping save on heating and cooling bills throughout the year.

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