How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the leading thermostat manufacturers, and we proudly install them on a frequent basis in Belleville. They’re sturdy and dependable. Also, Honeywell is constantly updating its technology, bringing more features for your family.

However, all thermostats can have troubles every so often. That’s why we’ve prepared this valuable handbook to run through troubleshooting.

While you can usually fix most thermostat issues by yourself, they sometimes call for Expert assistance. Our home comfort pros are here to help when you need us. We’re only a call away at 613-707-2421.

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

What Model of Thermostat Do I Have?

There are three types of thermostats:

  • Manual—This is the typical dial-shaped thermostat. You won’t run into error codes with this one, but it’s also the least efficient for reducing utility expenses.
  • Programmable—This thermostat includes a digital screen and arrows you touch to choose your desired temperature. You can also use daily programs to lower the temperature when you’re away and set it higher when you come home.
  • Smart—You won’t have to set any programs on this thermostat, because it picks up on your routine. It instinctively raises and lowers the temperature when you or family members are gone to help you save on energy costs. You can also raise or lower the temperature anywhere via your phone or other Wi-Fi-enabled device. 

As you’re aware many technologically advanced products, there are regular malfunctions that might happen. Most of these troubles don’t call for Expert support and are uncomplicated enough to solve by yourself.

Common Honeywell Thermostat Issues

All thermostats have a unique set of codes matching the problems that occur.

Think how easy it can be to restore a computer by restarting it. For the most part, diagnosing a thermostat can be just as simple.

Here are some of the most encountered Honeywell thermostat problems. These are applicable to the following programmable thermostats:

Display is Blank

If the screen is blank on your programmable thermostat, you may need to replace the batteries. If that doesn’t fix the malfunction or you have a smart thermostat, there may be a wiring malfunction.

Next, you should check the power is flowing for your furnace or air handler. Make sure the switch by the indoor unit is switched “up”.

Also, you should make sure all furnace cabinet or air handler doors/panels are securely in place.

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

Less frequently, a clear display may signify you should install a new thermostat.

Heating and Cooling Unit Won’t Work

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

In the summer, verify you put the thermostat lower than the room temperature. When it’s cold, verify it’s higher. This sounds goofy, but we’ve seen it take place many times.

Confirm the power switch by 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 current to the equipment.

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

“Cool On” or “Heat On” is Flashing

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

Then, make sure it’s calling for the appropriate system to run. This is usually demonstrated by “cool on,” “heat on” or a picture.

If these words or the icon is flashing, your thermostat is in a five-minute delay status. This feature protects your system from harmful short cycling. This could occur if your power is interrupted.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump needs service. Call D & K Heating Service Experts at 613-707-2421 for help.
  • 168—Wi-Fi radio error. Call 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 run.
  • 173—Thermostat temperature sensor error. Call Lyric technical support at 800-633-3991.
  • 175—AC power restarted. No action needed.
  • 181/182—Replace air filter. Clear the screen by tapping “dismiss” after putting in a clean filter.
  • 184—Replace humidifier pad. Clear the display by tapping “dismiss” after adding a new pad filter.
  • 185—Put in a new dehumidifier filter. Clear the display by hitting “dismiss” after putting in a clean filter.
  • 187—Rinse or install a new ventilator filter. Clear the screen by tapping “dismiss” after installing a clean filter.
  • 188/189—Install a new UV bulb. Call D & K Heating Service Experts at 613-707-2421 for assistance.
  • 210—Register online for outside temperature. Get the Lyric app to finish this step and ensure accurate thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Download 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. Download the Lyric app and follow the process to link your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump requires service. Contact D & K Heating Service Experts at 613-707-2421 for help.
  • 168—Wi-Fi radio error. Contact D & K Heating Service Experts at 613-707-2421 for support.
  • 170—Internal memory error. Contact D & K Heating Service Experts at 613-707-2421 for assistance.
  • 171—Set date and time. Finish these settings so scheduling can operate.
  • 173—Thermostat temperature sensor error. Contact D & K Heating Service Experts at 613-707-2421 for assistance.
  • 175—AC power reconnected. No action required.
  • 177—Indoor temperature sensor error. Contact D & K Heating Service Experts at 613-707-2421 for support.
  • 178—Outdoor temperature sensor error. Reach D & K Heating Service Experts at 613-707-2421 for assistance.
  • 181/182—Install a new air filter. Clear the display by hitting “dismiss” after installing a fresh filter.
  • 183—Wash humidifier tank and replace water filter. Clear the display by hitting “dismiss” after finishing these tasks.
  • 184—Install a new humidifier pad. Clear the monitor by hitting “dismiss” after installing pad filter.
  • 185—Replace dehumidifier filter. Clear the display by touching “dismiss” after adding a new filter.
  • 186—Rinse ventilator core. Clear the monitor by tapping “dismiss” after completing this task.
  • 187—Rinse or install a new ventilator filter. Clear the screen by hitting “dismiss” after installing a new filter.
  • 188/189—Add a new UV bulb. Get in touch with D & K Heating Service Experts at 613-707-2421 for assistance.
  • 210—Register online for exterior temperature. Use the Lyric app to complete this step and ensure correct thermostat operation.
  • 388—Register online for remote access and outside temperature. Use the Lyric app to complete this step and ensure proper 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. Get the Lyric app and follow the procedures to connect your thermostat.

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

Our Experts are Here to Provide Assistance

If you’re still running into troubles after going through the troubleshooting process, our Experts are ready to assist you. Call us at 613-707-2421 and we’ll be out quickly to diagnose the problem.

If you have an older thermostat, today is a fantastic time to think over a replacement. Thermostat technology has come a long way over the last few years. Ask us for more info on how smart thermostats can make your residence more comfortable while helping save on energy expenses all year.

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