How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the top thermostat brands, and we proudly install them on a frequent basis in Grand Island. They’re durable and reliable. In addition, Honeywell is constantly improving its technology, resulting in more features for your family.

Nevertheless, all thermostats can have issues once in awhile. That’s why we’ve put together this helpful handbook to walk you through troubleshooting.

While you can usually solve the majority of thermostat issues on your own, they occasionally call for Expert support. Our heating and cooling Experts are ready to support you when you need us. We’re just a call away at 308-210-4398.

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

What Type of Thermostat Do I Have?

There are three models of thermostats:

  • Manual—This is the typical dial-shaped thermostat. You won’t have error codes with this kind, but it’s also the least efficient for saving on energy expenses.
  • Programmable—This thermostat includes a digital screen and arrows you touch to set your desired temperature. You can also choose daily programs to reduce the temperature when you’re away and increase it when you get back.
  • Smart—You won’t have to make any programs on this thermostat, as it picks up on your routine. It automatically adjusts the temperature when you or family members are gone to help you save on heating and cooling costs. You can also raise or lower the temperature anywhere on your phone or other Wi-Fi-enabled device. 

As is the case with many technologically advanced products, there are several malfunctions that can take place. Many of these problems don’t call for Expert help and are simple to fix by yourself.

Common Honeywell Thermostat Troubles

Each thermostat has an exclusive set of codes matching the glitches that occur.

Think how uncomplicated it can be to repair a computer by restarting it. Many times, troubleshooting a thermostat can be just as simple.

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

Display is Blank

If the monitor is blank on your programmable thermostat, you may need to put in new batteries. If that doesn’t take care of the issue or you use a smart thermostat, there may be a wiring problem.

Next, you should ensure the power is enabled for your furnace or air handler. Confirm 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 fastened.

An unsecured panel may trigger the safety switch, which cuts off power to the unit.

While it’s less common, a blank monitor could signify you need to get a new thermostat.

Comfort Unit Won’t Turn On

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

During warm weather, verify you set the thermostat lower than the ambient temperature. In the winter, verify it’s higher. This sounds goofy, but we’ve seen it happen a lot of times.

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

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

“Cool On” or “Heat On” is Flickering

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

Then, ensure it’s telling the appropriate unit to turn on. This is usually demonstrated by “cool on,” “heat on” or an icon.

If these words or the illustration is pulsing, your thermostat is in a five-minute delay state. This setting protects your unit from bad short cycling. This can occur if you lose power.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump requires service. Call McElroy Service Experts at 308-210-4398 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. Complete 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 necessary.
  • 181/182—Install a new air filter. Clear the monitor by touching “dismiss” after putting in a clean filter.
  • 184—Put in a new humidifier pad. Clear the display by touching “dismiss” after adding a clean pad filter.
  • 185—Install a new dehumidifier filter. Clear the monitor by tapping “dismiss” after putting in a fresh filter.
  • 187—Clean or put in a new ventilator filter. Clear the screen by hitting “dismiss” after installing a new filter.
  • 188/189—Replace UV bulb. Call McElroy Service Experts at 308-210-4398 for assistance.
  • 210—Register online for outside temperature. Get the Lyric app to finish this step and ensure proper thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Use the Lyric app to finish this step and ensure proper thermostat operation.
  • 399—No Internet. Confirm your network settings.
  • 400—No Wi-Fi signal. Wait for the thermostat to reconnect or choose new Wi-Fi network.
  • 508—Wi-Fi not set up. Use the Lyric app and follow the process to configure your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump requires service. Call McElroy Service Experts at 308-210-4398 for help.
  • 168—Wi-Fi radio error. Contact McElroy Service Experts at 308-210-4398 for assistance.
  • 170—Internal memory error. Call McElroy Service Experts at 308-210-4398 for assistance.
  • 171—Set date and time. Finalize these settings so scheduling can work.
  • 173—Thermostat temperature sensor error. Contact McElroy Service Experts at 308-210-4398 for support.
  • 175—AC power reconnected. No action required.
  • 177—Indoor temperature sensor error. Call McElroy Service Experts at 308-210-4398 for assistance.
  • 178—Outdoor temperature sensor error. Call McElroy Service Experts at 308-210-4398 for help.
  • 181/182—Get a new air filter. Clear the display by touching “dismiss” after installing a new filter.
  • 183—Wash humidifier tank and replace water filter. Clear the thermostat by tapping “dismiss” after completing these procedures.
  • 184—Install a new humidifier pad. Clear the screen by tapping “dismiss” after installing pad filter.
  • 185—Replace dehumidifier filter. Clear the display by touching “dismiss” after putting in a new filter.
  • 186—Clean ventilator core. Clear the thermostat by touching “dismiss” after finishing this task.
  • 187—Rinse or get a new ventilator filter. Clear the screen by tapping “dismiss” after installing a new filter.
  • 188/189—Add a new UV bulb. Reach McElroy Service Experts at 308-210-4398 for assistance.
  • 210—Register online for outdoor temperature. Get the Lyric app to finish this step and ensure proper thermostat operation.
  • 388—Register online for remote access and outside temperature. Use the Lyric app to do this step and ensure correct thermostat operation.
  • 399—No Internet. Confirm your network settings.
  • 400—No Wi-Fi signal. Wait for the thermostat to reconnect or choose new Wi-Fi network.
  • 508—Wi-Fi not configured. Download the Lyric app and follow the procedures to connect your thermostat.

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

Our Experts are Available to Provide Support

If you’re still having troubles after going through the troubleshooting list, our pros are here to support you. Reach us at 308-210-4398 and we’ll arrive quickly to figure out the malfunction.

If you have an aging thermostat, today is a great time to think about a new device. Thermostat technology has advanced in recent years Ask us for more info on how smart thermostats can make your house more convenient while helping save on heating and cooling bills throughout the year.

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