How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the best thermostat brands, and we proudly install them on a frequent basis in Orlando. They’re durable and reliable. Also, Honeywell is regularly enhancing its technology, offering more features for your home.

Nevertheless, every thermostat can have issues occasionally. That’s why we’ve put together this helpful guide to run through troubleshooting.

While you can often repair many thermostat issues alone, they sometimes call for Expert help. Our heating and cooling professionals 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 Type of Thermostat Do I Have?

There are three kinds of thermostats:

  • Manual—This is the older dial-shaped thermostat. You won’t have error codes with this one, but it’s also the least efficient for saving on heating and cooling costs.
  • Programmable—This thermostat includes a digital screen and arrows you touch to choose your desired temperature. You can also choose daily programs to lower the temperature when you’re gone and increase it when you get back.
  • Smart—You won’t have to schedule any programs on this thermostat, since it picks up on your routine. It instinctively raises and lowers the temperature when you or loved ones are out and about 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 know most technologically advanced products, there are several glitches that might happen. Most of these issues don’t call for pro support and are uncomplicated enough to repair on your own.

Common Honeywell Thermostat Problems

Each thermostat has an exclusive 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 include 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 fix the trouble or you rely on a smart thermostat, there might be a wiring issue.

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

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

A loose panel may trigger the safety switch, which disconnects power to the unit.

Less frequently, a blank display may mean you need to get a new thermostat.

HVAC Equipment 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, confirm it’s higher. This sounds goofy, but we’ve seen it occur a lot of times.

Confirm the power switch close to your indoor equipment is in the “on” position. You should also check the cabinet doors or panels are tight on your furnace cabinet or air handler. An unsecured panel can trip the safety switch, diverting electricity to the unit.

Heating or cooling still won’t turn on? Make sure 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 set to “cool” or “heat.”

Then, ensure it’s telling the correct system to run. This is typically demonstrated by “cool on,” “heat on” or an illustration.

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 may happen if your power is interrupted.

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. 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. 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 exterior temperature. Use 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 finish 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. Download the Lyric app and follow the procedure to link your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump requires service. Call Service Experts Heating & Air Conditioning at 407-329-7661 for support.
  • 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 support.
  • 171—Set date and time. Finish these settings so scheduling can operate.
  • 173—Thermostat temperature sensor error. Reach Service Experts Heating & Air Conditioning at 407-329-7661 for assistance.
  • 175—AC power restored. No action needed.
  • 177—Indoor temperature sensor error. Contact 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 fresh filter.
  • 183—Clean humidifier tank and replace water filter. Clear the monitor by touching “dismiss” after completing these tasks.
  • 184—Get 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 clean filter.
  • 186—Clean ventilator core. Clear the screen by tapping “dismiss” after completing this task.
  • 187—Clean or get a new ventilator filter. Clear the display by tapping “dismiss” after installing a new filter.
  • 188/189—Install a new UV bulb. Reach 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. Get the Lyric app to complete 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 select new Wi-Fi network.
  • 508—Wi-Fi not connected. Download 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 Provide Assistance

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

If you have an aging thermostat, right now is a fantastic time to consider a replacement. Thermostat technology has gotten better over the last few years. Ask us for more information on how smart thermostats can make your house comfier while helping save on heating and cooling expenses year-round.

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