How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the top thermostat manufacturers, and we proudly install them on a usual basis in Voorhees. They’re sturdy and reliable. In addition, Honeywell is regularly improving its technology, bringing more features for your home.

Still, all thermostats can run into troubles every now and then. Due to this, we’ve compiled this informative handbook to walk you through troubleshooting.

While you can often repair most thermostat problems alone, they often call for Expert support. Our HVAC Experts are available to support you when you need us. We’re merely a call away at 856-310-4824.

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

What Type of Thermostat Do I Have?

There are three models of thermostats:

  • Manual—This is the classic dial-shaped thermostat. You won’t experience error codes with this kind, but it’s also the least efficient for reducing heating and cooling bills.
  • Programmable—This thermostat features a digital screen and arrows you press to choose your desired temperature. You can also use daily programs to lower the temperature when you’re away and raise it when you come home.
  • Smart—You won’t have to set any programs on this thermostat, because it learns your day. It intuitively raises and lowers the temperature when you or loved ones are away to help you save on energy expenses. You can also change the temperature anywhere on your phone or other Wi-Fi-enabled device. 

As is the case with many technologically advanced solutions, there are regular malfunctions that can happen. Many of these troubles don’t need professional assistance and are simple to solve on your own.

Common Honeywell Thermostat Problems

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

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

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

Display is Blank

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

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

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

A panel that isn’t tight may activate the safety switch, which stops power to the equipment.

Infrequently, a blank monitor might indicate you should get a new thermostat.

Comfort Equipment Won’t Start

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

During warm weather, make sure you set the thermostat below the ambient temperature. When it’s cold, make sure it’s higher. This sounds goofy, but we’ve seen it occur a lot of times.

Make sure the power switch near your indoor equipment is in the “on” position. You should also make sure the cabinet doors or panels are secure on your furnace cabinet or air handler. A loose panel can trigger the safety switch, cutting off electricity to the unit.

Heating or cooling still won’t turn on? Make sure circuit breakers haven’t flipped and that your HVAC system isn’t showing error codes.

“Cool On” or “Heat On” is Flickering

To begin, confirm your thermostat is set to “cool” or “heat.”

Then, check it’s signaling the appropriate system to run. This is usually shown by “cool on,” “heat on” or an illustration.

If this set of words or the illustration is blinking, your thermostat is in a five-minute delay status. This mode protects your system from bad short cycling. This may take place if you lose electricity.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump must be serviced. Call Atmostemp Service Experts at 856-310-4824 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. Complete these settings so scheduling can take place.
  • 173—Thermostat temperature sensor error. Contact Lyric technical support at 800-633-3991.
  • 175—AC power restored. No action needed.
  • 181/182—Install a new air filter. Clear the display by touching “dismiss” after adding a clean filter.
  • 184—Replace humidifier pad. Clear the screen by hitting “dismiss” after putting in a fresh pad filter.
  • 185—Replace dehumidifier filter. Clear the monitor by touching “dismiss” after adding a fresh filter.
  • 187—Wash or put in a new ventilator filter. Clear the monitor by touching “dismiss” after installing a clean filter.
  • 188/189—Replace UV bulb. Contact Atmostemp Service Experts at 856-310-4824 for support.
  • 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 do 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 choose new Wi-Fi network.
  • 508—Wi-Fi not set up. Get the Lyric app and follow the procedure to configure your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump needs service. Reach Atmostemp Service Experts at 856-310-4824 for assistance.
  • 168—Wi-Fi radio error. Contact Atmostemp Service Experts at 856-310-4824 for help.
  • 170—Internal memory error. Contact Atmostemp Service Experts at 856-310-4824 for support.
  • 171—Set date and time. Finalize these settings so scheduling can run.
  • 173—Thermostat temperature sensor error. Contact Atmostemp Service Experts at 856-310-4824 for assistance.
  • 175—AC power reconnected. No action needed.
  • 177—Indoor temperature sensor error. Call Atmostemp Service Experts at 856-310-4824 for help.
  • 178—Outdoor temperature sensor error. Call Atmostemp Service Experts at 856-310-4824 for assistance.
  • 181/182—Replace air filter. Clear the display by hitting “dismiss” after putting in a clean filter.
  • 183—Rinse humidifier tank and add a new water filter. Clear the screen by touching “dismiss” after doing these tasks.
  • 184—Get a new humidifier pad. Clear the screen by hitting “dismiss” after adding a new pad filter.
  • 185—Replace dehumidifier filter. Clear the thermostat by tapping “dismiss” after installing a fresh filter.
  • 186—Wash ventilator core. Clear the screen by tapping “dismiss” after doing this task.
  • 187—Clean or get a new ventilator filter. Clear the display by touching “dismiss” after buying a new filter.
  • 188/189—Replace UV bulb. Get in touch with Atmostemp Service Experts at 856-310-4824 for help.
  • 210—Register online for outdoor temperature. Get the Lyric app to finish 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. 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 configured. Download the Lyric app and follow the process to connect your thermostat.

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

Our Experts are Ready to Provide Assistance

If you’re still experiencing issues after working through the troubleshooting process, our professionals are available to support you. Reach us at 856-310-4824 and we’ll come to your house rapidly to diagnose the issue.

If you have an aging thermostat, now is a great time to think about a new device. Thermostat technology has advanced lately Ask us for more details on how smart thermostats can make your house more convenient while helping save on energy costs throughout the year.

Contact Us