How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the top thermostat manufacturers, and we proudly install them on a frequent basis in Fort Worth. They’re long-lasting and trustworthy. In addition, Honeywell is constantly improving its technology, bringing more features for your home.

Still, all thermostats can have issues every now and then. As a result, we’ve prepared this helpful guide to walk you through troubleshooting. While Honeywell thermostat problems are rare, they do pop up. 

While you can usually solve most thermostat problems alone, they often need Expert help. Our heating and cooling Experts are ready to help when you need us. We’re merely a call away at 817-380-5647.

Let’s begin the process by finding out what model of thermostat your residence has.

What Type of Thermostat Do I Have?

There are three kinds of thermostats:

  • Manual—This is the classic dial-shaped thermostat. You won’t experience error codes with this type, but it’s also the least efficient for lowering heating and cooling costs.
  • Programmable—This thermostat has a digital screen and arrows you press to set your desired temperature. You can also set daily programs to lower the temperature when you’re away and raise it when you return.
  • Smart—You won’t have to set any programs on this thermostat, as it learns your day. It intuitively raises and lowers the temperature when you or family members are away to help you save on heating and cooling expenses. You can also raise or lower the temperature anywhere on your phone or other Wi-Fi-enabled device. 

As you’re aware most technologically advanced products, there are regular malfunctions that may occur. Many of these problems don’t call for pro support and are uncomplicated enough to fix on your own.

Common Honeywell Thermostat Troubles

All thermostats have an exclusive set of codes that correspond to the issues that take place.

Think how uncomplicated it can be to repair a computer by restarting it. In many instances, troubleshooting a thermostat can be just as simple.

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

Display is Blank

If the monitor is clear on your programmable thermostat, you might need to install new batteries. If that doesn’t fix the malfunction or you have a smart thermostat, there might be a wiring issue.

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

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

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

Less frequently, an empty screen can signify you will need to get a new thermostat.

Heating and Cooling System Won’t Run

Make sure that your thermostat is set to “cool” or “heat,” not “off.”

During warm weather, confirm you schedule the thermostat beneath the room temperature. In the winter, make sure it’s higher. This sounds goofy, but we’ve seen it occur 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 tight on your furnace cabinet or air handler. A loose panel can activate the safety switch, cutting off current to the equipment.

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

“Cool On” or “Heat On” is Blinking

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

Then, make sure it’s telling the correct equipment to start. This is typically demonstrated by “cool on,” “heat on” or a picture.

If this phrase or the illustration is flashing, your thermostat is in a five-minute delay status. This feature protects your system from harmful short cycling. This may happen if you lose power.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump needs service. Call Calverley Service Experts at 817-380-5647 for help.
  • 168—Wi-Fi radio error. Reach 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 resumed. No action needed.
  • 181/182—Replace air filter. Clear the screen by touching “dismiss” after putting in a clean filter.
  • 184—Replace humidifier pad. Clear the screen by hitting “dismiss” after installing a new pad filter.
  • 185—Install a new dehumidifier filter. Clear the monitor by touching “dismiss” after installing a fresh filter.
  • 187—Wash or install a new ventilator filter. Clear the screen by touching “dismiss” after adding a fresh filter.
  • 188/189—Get a new UV bulb. Call Calverley Service Experts at 817-380-5647 for support.
  • 210—Register online for outside temperature. Use the Lyric app to finish this step and ensure correct thermostat operation.
  • 388—Register online for remote access and exterior temperature. Use the Lyric app to complete 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 pick new Wi-Fi network.
  • 508—Wi-Fi not set. Use the Lyric app and follow the process to configure your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump needs service. Reach Calverley Service Experts at 817-380-5647 for support.
  • 168—Wi-Fi radio error. Reach Calverley Service Experts at 817-380-5647 for support.
  • 170—Internal memory error. Reach Calverley Service Experts at 817-380-5647 for help.
  • 171—Set date and time. Complete these settings so scheduling can run.
  • 173—Thermostat temperature sensor error. Reach Calverley Service Experts at 817-380-5647 for support.
  • 175—AC power restored. No action needed.
  • 177—Indoor temperature sensor error. Call Calverley Service Experts at 817-380-5647 for assistance.
  • 178—Outdoor temperature sensor error. Contact Calverley Service Experts at 817-380-5647 for help.
  • 181/182—Get a new air filter. Clear the screen by touching “dismiss” after installing a new filter.
  • 183—Wash humidifier tank and replace water filter. Clear the display by touching “dismiss” after finishing these procedures.
  • 184—Replace humidifier pad. Clear the display by tapping “dismiss” after installing pad filter.
  • 185—Install a new dehumidifier filter. Clear the screen by tapping “dismiss” after installing a new filter.
  • 186—Rinse ventilator core. Clear the monitor by hitting “dismiss” after doing this task.
  • 187—Wash or install a new ventilator filter. Clear the screen by tapping “dismiss” after getting a new filter.
  • 188/189—Replace UV bulb. Reach Calverley Service Experts at 817-380-5647 for help.
  • 210—Register online for outdoor temperature. Use the Lyric app to do this step and ensure correct thermostat operation.
  • 388—Register online for remote access and exterior temperature. Download 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 select new Wi-Fi network.
  • 508—Wi-Fi not connected. Download the Lyric app and follow the procedures to connect your thermostat.

For more details, look at this thermostat’s user manual.

Our Experts are Ready to Provide Assistance

If you’re still running into troubles after going through the troubleshooting steps, our Experts are available to assist you. Give us a call at 817-380-5647 and we’ll be out rapidly to diagnose the problem.

If you have a dated thermostat, right now is a good time to think about a replacement. Thermostat technology has gotten better in recent years Ask us for more information on how smart thermostats can make your home better while helping save on heating and cooling costs all year.

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