How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the leading thermostat brands, and we proudly install them on a frequent basis in Raleigh. They’re durable and trustworthy. Also, Honeywell is frequently advancing its technology, bringing more features for your family.

However, every thermostat can run into errors at times. Due to this, we’ve compiled this helpful guide to go over troubleshooting.

While you can usually solve most thermostat problems on your own, they sometimes call for Expert support. Our HVAC pros are ready to assist you when you need us. We’re just a call away at 919-578-4329.

Let’s begin the process by determining what kind of thermostat your home 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 type, but it’s also the least efficient for lowering heating and cooling expenses.
  • Programmable—This thermostat has a digital screen and arrows you use to determine your desired temperature. You can also choose daily programs to reduce the temperature when you’re gone and increase it when you come home.
  • Smart—You won’t have to make any programs on this thermostat, because it learns your day. It automatically changes the temperature when you or other household members are gone to help you save on heating and cooling expenses. You can also change the temperature anywhere via your phone or other Wi-Fi-enabled device. 

As you’re aware many technologically advanced products, there are regular malfunctions that might occur. Many of these troubles don’t require professional help and are uncomplicated enough to solve alone.

Common Honeywell Thermostat Issues

Each thermostat has a unique set of codes that correspond to the troubles that take place.

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

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

Display is Blank

If the screen is blank on your programmable thermostat, you might need to get new batteries. If that doesn’t fix the issue or you have a smart thermostat, there may be a wiring malfunction.

Next, you should ensure the power is enabled for your furnace or air handler. Verify the switch by the indoor equipment is switched “up”.

Also, you should confirm all furnace cabinet or air handler doors/panels are tightly secured.

A loose panel may trip the safety switch, which stops power to the system.

Less frequently, an empty monitor may indicate you should buy a new thermostat.

HVAC Equipment Won’t Run

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

In the summer, confirm you schedule the thermostat beneath the room temperature. In the winter, make sure it’s higher. This sounds goofy, but we’ve seen it occur many times.

Make sure the power switch near your indoor equipment is in the “on” position. You should also check the cabinet doors or panels are closed on your furnace cabinet or air handler. A loose panel can activate the safety switch, stopping power to the unit.

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

“Cool On” or “Heat On” is Blinking

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

Then, make sure it’s signaling the right equipment to start. This is typically shown by “cool on,” “heat on” or an icon.

If this set of words or the illustration is pulsing, your thermostat is in a five-minute delay state. This mode stops your unit from bad short cycling. This can occur if you lose power.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump requires service. Call Service Experts Heating & Air Conditioning at 919-578-4329 for help.
  • 168—Wi-Fi radio error. Reach 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 needed.
  • 181/182—Put in a new air filter. Clear the thermostat by touching “dismiss” after putting in a new filter.
  • 184—Put in a new humidifier pad. Clear the screen by hitting “dismiss” after putting in a fresh pad filter.
  • 185—Install a new dehumidifier filter. Clear the display by hitting “dismiss” after adding a new filter.
  • 187—Clean or install a new ventilator filter. Clear the screen by hitting “dismiss” after adding a fresh filter.
  • 188/189—Install a new UV bulb. Contact Service Experts Heating & Air Conditioning at 919-578-4329 for help.
  • 210—Register online for outside temperature. Get the Lyric app to finish this step and ensure correct thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Use the Lyric app to do this step and ensure correct 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 up. Download 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 requires service. Contact Service Experts Heating & Air Conditioning at 919-578-4329 for help.
  • 168—Wi-Fi radio error. Reach Service Experts Heating & Air Conditioning at 919-578-4329 for assistance.
  • 170—Internal memory error. Call Service Experts Heating & Air Conditioning at 919-578-4329 for assistance.
  • 171—Set date and time. Finish these settings so scheduling can operate.
  • 173—Thermostat temperature sensor error. Call Service Experts Heating & Air Conditioning at 919-578-4329 for support.
  • 175—AC power restored. No action required.
  • 177—Indoor temperature sensor error. Contact Service Experts Heating & Air Conditioning at 919-578-4329 for support.
  • 178—Outdoor temperature sensor error. Call Service Experts Heating & Air Conditioning at 919-578-4329 for assistance.
  • 181/182—Replace air filter. Clear the screen by tapping “dismiss” after adding a new filter.
  • 183—Wash humidifier tank and install a new water filter. Clear the thermostat by tapping “dismiss” after doing these procedures.
  • 184—Get a new humidifier pad. Clear the display by touching “dismiss” after installing pad filter.
  • 185—Install a new dehumidifier filter. Clear the thermostat by tapping “dismiss” after adding a fresh filter.
  • 186—Rinse ventilator core. Clear the display by tapping “dismiss” after finishing this task.
  • 187—Clean or get a new ventilator filter. Clear the screen by touching “dismiss” after installing a new filter.
  • 188/189—Install a new UV bulb. Reach Service Experts Heating & Air Conditioning at 919-578-4329 for help.
  • 210—Register online for outside 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 finish 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 choose new Wi-Fi network.
  • 508—Wi-Fi not connected. Get the Lyric app and follow the process to connect your thermostat.

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

Our Experts are Available to Help

If you’re still having issues after working through the troubleshooting process, our professionals are available to assist you. Give us a call at 919-578-4329 and we’ll come to your house rapidly to determine the issue.

If you have an aging thermostat, today is a great time to think over a replacement. Thermostat technology has gotten better over the last few years. Ask us for more info on how smart thermostats can make your residence better while helping save on utility costs all year.

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