How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the best thermostat brands, and we proudly install them on a usual basis in Tempe. They’re long-lasting and dependable. Plus, Honeywell is regularly updating its technology, bringing more features for your house.

Still, all thermostats can have problems occasionally. Due to this, we’ve compiled this informative manual to go over troubleshooting.

While you can usually solve many thermostat problems by yourself, they occasionally require Expert help. Our heating and cooling pros are here to assist you when you need us. We’re just a call away at 623-243-4517.

Let’s get started with the process by determining what model of thermostat your home has.

What Type of Thermostat Do I Have?

There are three kinds of thermostats:

  • Manual—This is the older dial-shaped thermostat. You won’t run into error codes with this type, but it’s also the least efficient for saving on utility costs.
  • Programmable—This thermostat has a digital screen and arrows you touch to determine your desired temperature. You can also set daily programs to decrease the temperature when you’re away and raise it when you get back.
  • Smart—You won’t have to schedule any programs on this thermostat, as it picks up on your schedule. It automatically raises and lowers the temperature when you or other household members are away to help you save on energy bills. You can also raise or lower the temperature anywhere on your phone or other Wi-Fi-enabled device. 

As is the case with most technologically advanced things, there are regular malfunctions that may occur. The majority of of these situations don’t require Expert help and are easy to repair by yourself.

Common Honeywell Thermostat Problems

All thermostats have a unique group of codes matching the issues that occur.

Think how uncomplicated it can be to fix a computer by restarting it. For the most part, correcting a thermostat can be just as simple.

Here is a guide to the most encountered Honeywell thermostat problems. These are applicable to the following programmable thermostats:

Display is Blank

If the display is empty on your programmable thermostat, you might need to install new batteries. If that doesn’t take care of the issue or you use a smart thermostat, there might be a wiring malfunction.

Next, you should make sure the power is on for your furnace or air handler. Make sure the switch near the indoor system is switched “up”.

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

A panel that isn’t tight may trip the safety switch, which cuts off power to the unit.

While it’s less common, a clear display could mean you should get a new thermostat.

Comfort System Won’t Start

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

In the summer, verify you set the thermostat below the ambient temperature. When it’s cool, verify it’s higher. This sounds silly, but we’ve seen it occur lots of times.

Ensure the power switch close to your indoor equipment is in the “on” position. You should also check the cabinet doors or panels are tight on your furnace cabinet or air handler. An unsecured panel can activate the safety switch, diverting electricity to the equipment.

System still won’t turn on? Make sure circuit breakers haven’t tripped and that your HVAC system isn’t experiencing error codes.

“Cool On” or “Heat On” is Blinking

To start, confirm your thermostat is on “cool” or “heat.”

Then, ensure it’s signaling the right equipment to start. This is typically indicated by “cool on,” “heat on” or an illustration.

If this set of words or the illustration is flashing, your thermostat is in a five-minute delay mode. This setting keeps your unit from damaging short cycling. This can take place if you lose electricity.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump requires service. Call Bob Brown Service Experts at 623-243-4517 for help.
  • 168—Wi-Fi radio error. Call Lyric technical support at 800-633-3991. 170—Internal memory error. Call Lyric technical support at 800-633-3991.
  • 171—Set date and time. Complete these settings so scheduling can run.
  • 173—Thermostat temperature sensor error. Reach Lyric technical support at 800-633-3991.
  • 175—AC power restarted. No action necessary.
  • 181/182—Put in a new air filter. Clear the monitor by touching “dismiss” after putting in a fresh filter.
  • 184—Install a new humidifier pad. Clear the screen by hitting “dismiss” after adding a fresh pad filter.
  • 185—Put in a new dehumidifier filter. Clear the display by tapping “dismiss” after adding a new filter.
  • 187—Rinse or put in a new ventilator filter. Clear the thermostat by touching “dismiss” after adding a fresh filter.
  • 188/189—Replace UV bulb. Call Bob Brown Service Experts at 623-243-4517 for help.
  • 210—Register online for exterior temperature. Download the Lyric app to finish this step and ensure proper thermostat operation.
  • 388—Register online for remote access and outside temperature. Get the Lyric app to finish 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 pick new Wi-Fi network.
  • 508—Wi-Fi not configured. Use the Lyric app and follow the process to link your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump needs service. Contact Bob Brown Service Experts at 623-243-4517 for support.
  • 168—Wi-Fi radio error. Call Bob Brown Service Experts at 623-243-4517 for assistance.
  • 170—Internal memory error. Reach Bob Brown Service Experts at 623-243-4517 for support.
  • 171—Set date and time. Complete these settings so scheduling can operate.
  • 173—Thermostat temperature sensor error. Reach Bob Brown Service Experts at 623-243-4517 for help.
  • 175—AC power resumed. No action necessary.
  • 177—Indoor temperature sensor error. Reach Bob Brown Service Experts at 623-243-4517 for assistance.
  • 178—Outdoor temperature sensor error. Call Bob Brown Service Experts at 623-243-4517 for help.
  • 181/182—Get a new air filter. Clear the thermostat by touching “dismiss” after putting in a new filter.
  • 183—Wash humidifier tank and add a new water filter. Clear the thermostat by touching “dismiss” after completing these steps.
  • 184—Replace humidifier pad. Clear the screen by hitting “dismiss” after installing pad filter.
  • 185—Replace dehumidifier filter. Clear the screen by touching “dismiss” after installing a fresh filter.
  • 186—Wash ventilator core. Clear the display by tapping “dismiss” after doing this task.
  • 187—Rinse or get a new ventilator filter. Clear the monitor by hitting “dismiss” after installing a new filter.
  • 188/189—Install a new UV bulb. Contact Bob Brown Service Experts at 623-243-4517 for assistance.
  • 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 outdoor 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 select new Wi-Fi network.
  • 508—Wi-Fi not configured. Get the Lyric app and follow the process to connect your thermostat.

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

Our Experts are Available to Provide Assistance

If you’re still running into issues after trying the troubleshooting list, our pros are ready to assist you. Reach us at 623-243-4517 and we’ll be out quickly to determine the malfunction.

If you use a dated thermostat, now 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 convenient while helping save on energy costs all year.

Contact Us