How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the best thermostat brands, and we proudly install them on a regular basis in Orlando. They’re durable and dependable. Also, Honeywell is frequently advancing its technology, offering more features for your family.

Still, each thermostat can have errors every now and then. That’s why we’ve put together this informative manual to go over troubleshooting.

While you can typically repair the majority of thermostat issues alone, they sometimes call for Expert support. Our heating and cooling Experts are available to assist you when you need us. We’re only a call away at 407-329-7661.

Let’s start the process by finding out what type of thermostat your home has.

What Model of Thermostat Do I Have?

There are three kinds of thermostats:

  • Manual—This is the typical dial-shaped thermostat. You won’t experience error codes with this one, but it’s also the least efficient for saving on heating and cooling expenses.
  • Programmable—This thermostat features a digital screen and arrows you touch to determine your desired temperature. You can also choose daily programs to decrease the temperature when you’re gone and increase it when you return.
  • Smart—You won’t have to schedule any programs on this thermostat, as it adjusts to your routine. It instinctively changes the temperature when you or family members are gone to help you save on energy costs. You can also change the temperature anywhere via your phone or other Wi-Fi-enabled device. 

As you’re aware most technologically advanced products, there are regular malfunctions that may happen. Most of these troubles don’t call for Expert support and are simple to repair on your own.

Common Honeywell Thermostat Problems

Each thermostat has a special set of codes assigned to the issues that take place.

Think how easy it can be to restore a computer by restarting it. In most situations, troubleshooting a thermostat can be just as simple.

Here is a guide to the most encountered Honeywell thermostat issues. These apply to the following programmable thermostats:

Display is Blank

If the screen is empty on your programmable thermostat, you may need to get new batteries. If that doesn’t solve the trouble or you use a smart thermostat, there might be a wiring problem.

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

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

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

While it’s less common, a blank display can mean you need to replace your thermostat.

HVAC Unit Won’t Start

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

In the summer, make sure you set the thermostat lower than the current temperature. In the winter, verify it’s higher. This sounds absurd, but we’ve seen it take place a lot of times.

Ensure the power switch by your indoor system is in the “on” position. You should also comfirm the cabinet doors or panels are tight on your furnace cabinet or air handler. An unsecured panel can trip the safety switch, stopping current to the unit.

Heating or cooling still won’t turn on? Make sure circuit breakers haven’t tripped and that your HVAC unit isn’t experiencing error codes.

“Cool On” or “Heat On” is Blinking

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

Then, ensure it’s telling the right system to run. This is typically shown by “cool on,” “heat on” or a picture.

If these words or the illustration is flashing, your thermostat is in a five-minute delay mode. This mode stops your system from damaging short cycling. This could happen if you lose electricity.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump must be serviced. Call Service Experts Heating & Air Conditioning at 407-329-7661 for support.
  • 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 restored. No action necessary.
  • 181/182—Put in a new air filter. Clear the display by hitting “dismiss” after putting in a new filter.
  • 184—Replace humidifier pad. Clear the monitor by hitting “dismiss” after installing a new pad filter.
  • 185—Replace dehumidifier filter. Clear the monitor by tapping “dismiss” after putting in a fresh filter.
  • 187—Wash or install a new ventilator filter. Clear the monitor by touching “dismiss” after putting in a fresh filter.
  • 188/189—Get a new UV bulb. Contact Service Experts Heating & Air Conditioning at 407-329-7661 for assistance.
  • 210—Register online for outside temperature. Use the Lyric app to finish this step and ensure accurate thermostat operation.
  • 388—Register online for remote access and exterior temperature. Get the Lyric app to do this step and ensure accurate thermostat operation.
  • 399—No Internet. Verify 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 up. Download the Lyric app and follow the process to configure 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. Call Service Experts Heating & Air Conditioning at 407-329-7661 for help.
  • 168—Wi-Fi radio error. Call Service Experts Heating & Air Conditioning at 407-329-7661 for support.
  • 170—Internal memory error. Reach Service Experts Heating & Air Conditioning at 407-329-7661 for help.
  • 171—Set date and time. Finish these settings so scheduling can work.
  • 173—Thermostat temperature sensor error. Reach Service Experts Heating & Air Conditioning at 407-329-7661 for assistance.
  • 175—AC power reconnected. No action necessary.
  • 177—Indoor temperature sensor error. Reach Service Experts Heating & Air Conditioning at 407-329-7661 for assistance.
  • 178—Outdoor temperature sensor error. Call Service Experts Heating & Air Conditioning at 407-329-7661 for help.
  • 181/182—Install a new air filter. Clear the screen by tapping “dismiss” after adding a clean filter.
  • 183—Clean humidifier tank and replace water filter. Clear the screen by touching “dismiss” after completing these tasks.
  • 184—Install a new humidifier pad. Clear the monitor by touching “dismiss” after getting a new pad filter.
  • 185—Replace dehumidifier filter. Clear the monitor by touching “dismiss” after putting in a fresh filter.
  • 186—Clean ventilator core. Clear the display by hitting “dismiss” after finishing this task.
  • 187—Clean or install a new ventilator filter. Clear the display by tapping “dismiss” after installing a new filter.
  • 188/189—Install a new UV bulb. Get in touch with Service Experts Heating & Air Conditioning at 407-329-7661 for assistance.
  • 210—Register online for outside temperature. Use the Lyric app to complete this step and ensure proper thermostat operation.
  • 388—Register online for remote access and outside temperature. Use the Lyric app to complete this step and ensure correct thermostat operation.
  • 399—No Internet. Verify 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 up. Download the Lyric app and follow the procedures to connect your thermostat.

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

Our Experts are Here to Provide Assistance

If you’re still running into problems after trying the troubleshooting steps, our pros are available to help. Reach us at 407-329-7661 and we’ll come to your house quickly to diagnose the issue.

If you have a dated thermostat, today is a great time to consider a replacement. Thermostat technology has advanced over the last few years. Ask us for more information on how smart thermostats can make your residence comfier while helping save on heating and cooling costs year-round.

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