How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the top thermostat producers, and we proudly install them on a regular basis in La Porte. They’re long-lasting and dependable. In addition, Honeywell is regularly updating its technology, resulting in more features for your home.

Still, all thermostats can run into troubles once in awhile. That’s why we’ve prepared this useful guidebook to run through troubleshooting. While Honeywell thermostat problems are rare, they do occur. 

While you can usually solve many thermostat troubles alone, they occasionally require Expert help. Our heating and cooling professionals are ready to help when you need us. We’re merely a call away at 281-407-9478.

Let’s start the process by determining what type of thermostat your home has.

What Kind of Thermostat Do I Have?

There are three kinds of thermostats:

  • Manual—This is the classic dial-shaped thermostat. You won’t have error codes with this kind, but it’s also the least efficient for lowering heating and cooling bills.
  • Programmable—This thermostat has a digital screen and arrows you press to choose your desired temperature. You can also choose daily programs to reduce the temperature when you’re gone and increase it when you get back.
  • Smart—You won’t have to set any programs on this thermostat, as it adjusts to your routine. It automatically adjusts the temperature when you or loved ones are out and about to help you save on heating and cooling expenses. You can also raise or lower the temperature anywhere on your phone or other Wi-Fi-enabled device. 

As you know the majority of technologically advanced things, there are several malfunctions that may take place. Many of these situations don’t need Expert support and are uncomplicated enough to repair on your own.

Common Honeywell Thermostat Issues

All thermostats have an exclusive group of codes assigned to the troubles that happen.

Think how simple it can be to repair a computer by restarting it. In most situations, diagnosing a thermostat can be just as easy.

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

Display is Blank

If the screen is clear on your programmable thermostat, you might need to put in new batteries. If that doesn’t solve the problem or you rely on a smart thermostat, there could be a wiring malfunction.

Next, you should make sure the power is flowing for your furnace or air handler. Make sure the switch close to the indoor equipment is switched “on”.

Also, you should make certain all furnace cabinet or air handler doors/panels are sturdily secured.

An unsecured panel may activate the safety switch, which stops power to the unit.

Less frequently, an empty screen might mean you need to install a new thermostat.

Heating and Cooling Equipment Won’t Turn On

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

During warm weather, confirm you put the thermostat lower than the current temperature. In the winter, make sure it’s higher. This sounds silly, but we’ve seen it happen many 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 secure on your furnace cabinet or air handler. An unsecured panel can trigger the safety switch, diverting current to the equipment.

Equipment still won’t start? Verify circuit breakers haven’t turned off and that your HVAC system isn’t showing error codes.

“Cool On” or “Heat On” is Flickering

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

Then, check it’s calling for the correct unit to turn on. This is often demonstrated by “cool on,” “heat on” or an illustration.

If this phrase or the icon is flashing, your thermostat is in a five-minute delay mode. This feature protects your unit from bad short cycling. This may happen if you lose power.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump needs service. Call Finch Air Conditioning & Heating at 281-407-9478 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. Finish these settings so scheduling can take place.
  • 173—Thermostat temperature sensor error. Contact Lyric technical support at 800-633-3991.
  • 175—AC power restarted. No action needed.
  • 181/182—Put in a new air filter. Clear the monitor by hitting “dismiss” after putting in a fresh filter.
  • 184—Install a new humidifier pad. Clear the monitor by tapping “dismiss” after installing a fresh pad filter.
  • 185—Install a new dehumidifier filter. Clear the thermostat by touching “dismiss” after adding a clean filter.
  • 187—Rinse or replace ventilator filter. Clear the thermostat by hitting “dismiss” after putting in a fresh filter.
  • 188/189—Get a new UV bulb. Call Finch Air Conditioning & Heating at 281-407-9478 for help.
  • 210—Register online for outdoor temperature. Download the Lyric app to do this step and ensure accurate thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Get the Lyric app to finish 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 choose new Wi-Fi network.
  • 508—Wi-Fi not set. Get the Lyric app and follow the process to connect your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump needs service. Contact Finch Air Conditioning & Heating at 281-407-9478 for help.
  • 168—Wi-Fi radio error. Call Finch Air Conditioning & Heating at 281-407-9478 for help.
  • 170—Internal memory error. Call Finch Air Conditioning & Heating at 281-407-9478 for support.
  • 171—Set date and time. Finish these settings so scheduling can operate.
  • 173—Thermostat temperature sensor error. Call Finch Air Conditioning & Heating at 281-407-9478 for assistance.
  • 175—AC power resumed. No action needed.
  • 177—Indoor temperature sensor error. Contact Finch Air Conditioning & Heating at 281-407-9478 for assistance.
  • 178—Outdoor temperature sensor error. Call Finch Air Conditioning & Heating at 281-407-9478 for help.
  • 181/182—Get a new air filter. Clear the monitor by hitting “dismiss” after putting in a clean filter.
  • 183—Rinse humidifier tank and replace water filter. Clear the screen by hitting “dismiss” after doing these procedures.
  • 184—Replace humidifier pad. Clear the screen by tapping “dismiss” after getting a new pad filter.
  • 185—Get a new dehumidifier filter. Clear the monitor by tapping “dismiss” after adding a fresh filter.
  • 186—Wash ventilator core. Clear the monitor by touching “dismiss” after completing this task.
  • 187—Wash or get a new ventilator filter. Clear the monitor by hitting “dismiss” after getting a new filter.
  • 188/189—Get a new UV bulb. Get in touch with Finch Air Conditioning & Heating at 281-407-9478 for support.
  • 210—Register online for exterior temperature. Download the Lyric app to finish this step and ensure accurate thermostat operation.
  • 388—Register online for remote access and outside temperature. Download the Lyric app to complete this step and ensure correct 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 connected. Download the Lyric app and follow the procedures to connect your thermostat.

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

Our Experts are Available to Provide Support

If you’re still experiencing problems after working through the troubleshooting process, our pros are ready to help. Reach us at 281-407-9478 and we’ll be out rapidly to diagnose the problem.

If you have an older thermostat, today is a great time to consider a new thermostat. Thermostat technology has come a long way lately Ask us for more information on how smart thermostats can make your home comfier while helping save on utility expenses all year.

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