How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the top thermostat producers, and we proudly install them on a regular basis in Houston. They’re durable and dependable. Plus, Honeywell is frequently enhancing its technology, resulting in more features for your household.

However, every thermostat can experience problems occasionally. As a result, we’ve put together this informative manual to walk you through troubleshooting. While Honeywell thermostat problems are rare, they happen. 

While you can often solve most thermostat troubles on your own, they occasionally require Expert support. Our heating and cooling Experts are here to assist you when you need us. We’re just a call away at (713) 352-7887.

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

What Type of Thermostat Do I Have?

There are three types of thermostats:

  • Manual—This is the older dial-shaped thermostat. You won’t experience error codes with this one, but it’s also the least efficient for lowering energy expenses.
  • Programmable—This thermostat includes a digital screen and arrows you use to choose your desired temperature. You can also use daily programs to lower the temperature when you’re at work and increase it when you get back.
  • Smart—You won’t have to schedule any programs on this thermostat, since it picks up on your routine. It intuitively changes the temperature when you or other household members are away to help you save on energy bills. You can also change the temperature anywhere using your phone or other Wi-Fi-enabled device. 

As is the case with many technologically advanced things, there are several malfunctions that might happen. Many of these issues don’t require Expert help and are easy to solve alone.

Common Honeywell Thermostat Problems

Each thermostat has a special group of codes matching the glitches that occur.

Think how uncomplicated it can be to fix a computer by restarting it. In many instances, correcting a thermostat can be just as simple.

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

Display is Blank

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

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

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

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

While it’s less common, a clear monitor could indicate you need to install a new thermostat.

Comfort Unit Won’t Run

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

During warm weather, verify you put the thermostat below the room temperature. When it’s cold, verify it’s higher. This sounds silly, but we’ve seen it happen many times.

Confirm the power switch near your indoor system is in the “on” position. You should also comfirm the cabinet doors or panels are secure on your furnace cabinet or air handler. A loose panel can trigger the safety switch, diverting electricity to the unit.

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

“Cool On” or “Heat On” is Blinking

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

Then, ensure it’s telling the correct system to run. This is often demonstrated by “cool on,” “heat on” or an icon.

If these words or the picture is pulsing, your thermostat is in a five-minute delay status. This setting protects your unit from damaging short cycling. This may occur if your power is interrupted.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump needs service. Call Service Experts Heating & Air Conditioning at (713) 352-7887 for assistance.
  • 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. Reach Lyric technical support at 800-633-3991.
  • 175—AC power restarted. No action required.
  • 181/182—Put in a new air filter. Clear the screen by hitting “dismiss” after adding a clean filter.
  • 184—Put in a new humidifier pad. Clear the display by tapping “dismiss” after putting in a fresh pad filter.
  • 185—Replace dehumidifier filter. Clear the thermostat by tapping “dismiss” after adding a new filter.
  • 187—Wash or install a new ventilator filter. Clear the display by hitting “dismiss” after adding a new filter.
  • 188/189—Replace UV bulb. Contact Service Experts Heating & Air Conditioning at (713) 352-7887 for help.
  • 210—Register online for exterior temperature. Use the Lyric app to do 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. Confirm your network settings.
  • 400—No Wi-Fi signal. Wait for the thermostat to reconnect or choose new Wi-Fi network.
  • 508—Wi-Fi not configured. Get the Lyric app and follow the steps to connect your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump must be serviced service. Call Service Experts Heating & Air Conditioning at (713) 352-7887 for help.
  • 168—Wi-Fi radio error. Reach Service Experts Heating & Air Conditioning at (713) 352-7887 for assistance.
  • 170—Internal memory error. Call Service Experts Heating & Air Conditioning at (713) 352-7887 for assistance.
  • 171—Set date and time. Complete these settings so scheduling can run.
  • 173—Thermostat temperature sensor error. Contact Service Experts Heating & Air Conditioning at (713) 352-7887 for help.
  • 175—AC power resumed. No action needed.
  • 177—Indoor temperature sensor error. Call Service Experts Heating & Air Conditioning at (713) 352-7887 for help.
  • 178—Outdoor temperature sensor error. Call Service Experts Heating & Air Conditioning at (713) 352-7887 for assistance.
  • 181/182—Get a new air filter. Clear the thermostat by tapping “dismiss” after putting in a new filter.
  • 183—Clean humidifier tank and add a new water filter. Clear the screen by tapping “dismiss” after doing these procedures.
  • 184—Replace humidifier pad. Clear the screen by tapping “dismiss” after getting a new pad filter.
  • 185—Install a new dehumidifier filter. Clear the thermostat by tapping “dismiss” after putting in a clean filter.
  • 186—Wash ventilator core. Clear the monitor by hitting “dismiss” after completing this task.
  • 187—Rinse or get a new ventilator filter. Clear the screen by tapping “dismiss” after getting a new filter.
  • 188/189—Replace UV bulb. Reach Service Experts Heating & Air Conditioning at (713) 352-7887 for help.
  • 210—Register online for outdoor temperature. Use the Lyric app to finish this step and ensure correct thermostat operation.
  • 388—Register online for remote access and exterior temperature. Use the Lyric app to complete this step and ensure proper 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 configured. Download the Lyric app and follow the procedures to connect your thermostat.

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

Our Experts are Available to Provide Support

If you’re still having problems after going through the troubleshooting list, our pros are here to help. Call us at (713) 352-7887 and we’ll arrive rapidly to figure out the malfunction.

If you rely on a dated thermostat, today is a fantastic time to think over a replacement. Thermostat technology has advanced in recent years Ask us for more details on how smart thermostats can make your home comfier while helping save on energy costs year-round.

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