How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the leading thermostat brands, and we proudly install them on a frequent basis in Savannah. They’re long-lasting and dependable. Also, Honeywell is frequently updating its technology, offering more features for your family.

However, each thermostat can run into problems at one time or another. That’s why we’ve put together this informative manual to run through troubleshooting.

While you can usually repair the majority of thermostat issues alone, they sometimes require Expert assistance. Our heating and cooling pros are here to assist you when you need us. We’re only a call away at 912-208-2399.

Let’s start the process by finding out what kind of thermostat your residence has.

What Type of Thermostat Do I Have?

There are three models of thermostats:

  • Manual—This is the typical dial-shaped thermostat. You won’t experience error codes with this type, but it’s also the least efficient for saving on utility expenses.
  • Programmable—This thermostat features a digital screen and arrows you touch to set your desired temperature. You can also use daily programs to reduce the temperature when you’re away and increase it when you get back.
  • Smart—You won’t have to set any programs on this thermostat, because it learns your day. It automatically adjusts the temperature when you or other household members are out and about to help you save on heating and cooling costs. You can also change the temperature anywhere using your phone or other Wi-Fi-enabled device. 

As is the case with the majority of technologically advanced things, there are several problems that might happen. Most of these troubles don’t require Expert help and are easy to solve alone.

Common Honeywell Thermostat Problems

Each thermostat has a special group of codes that correspond to the problems that take place.

Think how easy it can be to fix a computer by restarting it. In most cases, diagnosing a thermostat can be just as uncomplicated.

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

Display is Blank

If the monitor is empty on your programmable thermostat, you may need to put in new batteries. If that doesn’t take care of the problem or you rely on a smart thermostat, there might be a wiring malfunction.

Next, you should check the power is on for your furnace or air handler. Verify the switch near the indoor system is in the “on” position.

Additionally, you should make sure all furnace cabinet or air handler doors/panels are securely secured.

An unsecured panel may trip the safety switch, which stops power to the equipment.

Infrequently, an empty screen could indicate you will need to replace your thermostat.

Heating and Cooling Unit Won’t Start

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

During warm weather, verify you schedule the thermostat lower than the current temperature. When it’s cool, confirm it’s higher. This sounds goofy, but we’ve seen it happen lots of times.

Ensure the power switch near your indoor system is in the “on” position. You should also make sure the cabinet doors or panels are closed on your furnace cabinet or air handler. An open panel can activate the safety switch, stopping electricity to the equipment.

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

“Cool On” or “Heat On” is Flashing

First, make sure your thermostat is on “cool” or “heat.”

Then, check it’s signaling the appropriate equipment to start. This is typically shown by “cool on,” “heat on” or a picture.

If these words or the illustration is flashing, your thermostat is in a five-minute delay state. This mode 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 must be serviced. Call Coastal Service Experts at 912-208-2399 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. Complete these settings so scheduling can occur.
  • 173—Thermostat temperature sensor error. Reach 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 hitting “dismiss” after installing a new filter.
  • 184—Install a new humidifier pad. Clear the display by hitting “dismiss” after adding a fresh pad filter.
  • 185—Put in a new dehumidifier filter. Clear the screen by touching “dismiss” after adding a clean filter.
  • 187—Rinse or install a new ventilator filter. Clear the display by touching “dismiss” after installing a clean filter.
  • 188/189—Install a new UV bulb. Contact Coastal Service Experts at 912-208-2399 for support.
  • 210—Register online for outside temperature. Use the Lyric app to do this step and ensure proper thermostat operation.
  • 388—Register online for remote access and outside temperature. Use the Lyric app to finish this step and ensure accurate 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 up. Use the Lyric app and follow the process to connect your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump requires service. Contact Coastal Service Experts at 912-208-2399 for support.
  • 168—Wi-Fi radio error. Reach Coastal Service Experts at 912-208-2399 for help.
  • 170—Internal memory error. Contact Coastal Service Experts at 912-208-2399 for support.
  • 171—Set date and time. Complete these settings so scheduling can operate.
  • 173—Thermostat temperature sensor error. Reach Coastal Service Experts at 912-208-2399 for assistance.
  • 175—AC power reconnected. No action necessary.
  • 177—Indoor temperature sensor error. Contact Coastal Service Experts at 912-208-2399 for assistance.
  • 178—Outdoor temperature sensor error. Contact Coastal Service Experts at 912-208-2399 for support.
  • 181/182—Get a new air filter. Clear the display by tapping “dismiss” after installing a fresh filter.
  • 183—Clean humidifier tank and replace water filter. Clear the monitor by hitting “dismiss” after finishing these steps.
  • 184—Install a new humidifier pad. Clear the thermostat by tapping “dismiss” after adding a new pad filter.
  • 185—Install a new dehumidifier filter. Clear the display by hitting “dismiss” after putting in a clean filter.
  • 186—Clean ventilator core. Clear the display by hitting “dismiss” after doing this task.
  • 187—Clean or install a new ventilator filter. Clear the monitor by tapping “dismiss” after getting a new filter.
  • 188/189—Install a new UV bulb. Contact Coastal Service Experts at 912-208-2399 for assistance.
  • 210—Register online for outdoor temperature. Download the Lyric app to do this step and ensure correct thermostat operation.
  • 388—Register online for remote access and outside temperature. Get 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 configured. Use the Lyric app and follow the process to connect your thermostat.

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

Our Experts are Here to Provide Support

If you’re still running into troubles after going through the troubleshooting steps, our Experts are ready to support you. Call us at 912-208-2399 and we’ll arrive as fast as we can to diagnose the issue.

If you have an aging thermostat, now is a great time to think over a new thermostat. 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 heating and cooling expenses year-round.

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