How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the leading thermostat brands, and we proudly install them on a regular basis in Clearwater. They’re sturdy and dependable. Also, Honeywell is frequently improving its technology, resulting in more features for your house.

However, all thermostats can have troubles now and then. That’s why we’ve prepared this valuable guide to run through troubleshooting.

While you can typically solve the majority of thermostat problems on your own, they often need Expert help. Our home comfort pros are ready to help when you need us. We’re only a call away at 727-219-2471.

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

What Model of Thermostat Do I Have?

There are three types of thermostats:

  • Manual—This is the older dial-shaped thermostat. You won’t run into error codes with this one, but it’s also the least efficient for reducing utility bills.
  • Programmable—This thermostat has a digital screen and arrows you use to choose your desired temperature. You can also choose daily programs to lower the temperature when you’re at work and raise it when you come home.
  • Smart—You won’t have to set any programs on this thermostat, since it learns your schedule. It intuitively raises and lowers the temperature when you or loved ones are out and about to help you save on energy bills. You can also raise or lower the temperature anywhere via your phone or other Wi-Fi-enabled device. 

As is the case with the majority of technologically advanced things, there are regular problems that might happen. Many of these troubles don’t require pro support and are simple to repair by yourself.

Common Honeywell Thermostat Problems

Each thermostat has a special group of codes that correspond to the troubles that occur.

Think how easy it can be to repair a computer by restarting it. Many times, correcting a thermostat can be just as easy.

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

Display is Blank

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

Next, you should check the power is flowing for your furnace or air handler. Verify the switch close to the indoor system is switched “on”.

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

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

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

Comfort Equipment Won’t Start

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

When it’s hot, verify you schedule the thermostat lower than the current temperature. In the winter, make sure it’s higher. This sounds silly, but we’ve seen it take place lots of times.

Ensure the power switch near your indoor equipment 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 trigger the safety switch, diverting power to the unit.

System still won’t run? Verify circuit breakers haven’t tripped and that your HVAC equipment isn’t displaying error codes.

“Cool On” or “Heat On” is Blinking

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

Then, make sure it’s telling the correct system to start. This is typically indicated by “cool on,” “heat on” or an icon.

If this set of words or the illustration is pulsing, your thermostat is in a five-minute delay mode. This setting protects your unit from harmful short cycling. This could occur if you lose power.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump needs service. Call Midway Services at 727-219-2471 for help.
  • 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. Complete these settings so scheduling can run.
  • 173—Thermostat temperature sensor error. Contact Lyric technical support at 800-633-3991.
  • 175—AC power restarted. No action required.
  • 181/182—Install a new air filter. Clear the thermostat by tapping “dismiss” after installing a fresh filter.
  • 184—Replace humidifier pad. Clear the display by hitting “dismiss” after installing a clean pad filter.
  • 185—Install a new dehumidifier filter. Clear the screen by hitting “dismiss” after installing a clean filter.
  • 187—Wash or put in a new ventilator filter. Clear the thermostat by hitting “dismiss” after putting in a clean filter.
  • 188/189—Replace UV bulb. Contact Midway Services at 727-219-2471 for help.
  • 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 exterior temperature. Use the Lyric app to do 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 set. Get the Lyric app and follow the steps to link your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump needs service. Call Midway Services at 727-219-2471 for assistance.
  • 168—Wi-Fi radio error. Reach Midway Services at 727-219-2471 for help.
  • 170—Internal memory error. Call Midway Services at 727-219-2471 for assistance.
  • 171—Set date and time. Complete these settings so scheduling can operate.
  • 173—Thermostat temperature sensor error. Reach Midway Services at 727-219-2471 for assistance.
  • 175—AC power restored. No action required.
  • 177—Indoor temperature sensor error. Reach Midway Services at 727-219-2471 for help.
  • 178—Outdoor temperature sensor error. Call Midway Services at 727-219-2471 for help.
  • 181/182—Install a new air filter. Clear the screen by tapping “dismiss” after adding a clean filter.
  • 183—Rinse humidifier tank and add a new water filter. Clear the display by tapping “dismiss” after completing these tasks.
  • 184—Get a new humidifier pad. Clear the screen by tapping “dismiss” after adding a new pad filter.
  • 185—Install a new dehumidifier filter. Clear the monitor by hitting “dismiss” after putting in a new filter.
  • 186—Clean ventilator core. Clear the monitor by tapping “dismiss” after finishing this task.
  • 187—Wash or get a new ventilator filter. Clear the display by hitting “dismiss” after installing a new filter.
  • 188/189—Replace UV bulb. Get in touch with Midway Services at 727-219-2471 for help.
  • 210—Register online for outdoor temperature. Get 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 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 up. Use the Lyric app and follow the steps to connect your thermostat.

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

Our Experts are Ready to Help

If you’re still experiencing troubles after working through the troubleshooting list, our Experts are ready to support you. Call us at 727-219-2471 and we’ll come to your house quickly to determine the malfunction.

If you rely on a dated thermostat, now is a great time to think about a replacement. Thermostat technology has come a long way over the last few years. Ask us for more details on how smart thermostats can make your home more convenient while helping save on heating and cooling expenses all year.

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