How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the leading thermostat manufacturers, and we proudly install them on a regular basis in Longmont. They’re sturdy and trustworthy. Also, Honeywell is regularly improving its technology, resulting in more features for your family.

Nevertheless, every thermostat can experience problems occasionally. As a result, we’ve put together this useful guidebook to go over troubleshooting.

While you can often fix most thermostat issues alone, they sometimes require Expert assistance. Our heating and cooling professionals are here to support you when you need us. We’re just a call away at 303-647-5749.

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

What Model 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 energy costs.
  • Programmable—This thermostat has a digital screen and arrows you use to set your desired temperature. You can also set daily programs to lower the temperature when you’re gone and raise it when you come home.
  • Smart—You won’t have to set any programs on this thermostat, because it learns your routine. It intuitively changes the temperature when you or family members are gone to help you save on heating and cooling bills. You can also adjust the temperature anywhere using your phone or other Wi-Fi-enabled device. 

As you know the majority of technologically advanced solutions, there are several malfunctions that can take place. Most of these problems don’t need Expert help and are uncomplicated enough to fix alone.

Common Honeywell Thermostat Troubles

Every thermostat has an exclusive set of codes that correspond to the problems that occur.

Think how simple 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 common Honeywell thermostat problems. These are applicable to the following programmable thermostats:

Display is Blank

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

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

In addition to that, you should confirm all furnace cabinet or air handler doors/panels are securely secured.

An unsecured panel may activate the safety switch, which disconnects power to the system.

While it’s less common, a blank display can signify you will need to buy a new thermostat.

HVAC Unit Won’t Work

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

In the summer, confirm you schedule the thermostat below the room temperature. In the winter, verify it’s higher. This sounds goofy, but we’ve seen it take place a lot of times.

Confirm the power switch by 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 trip the safety switch, cutting off power to the system.

Unit still won’t turn on? Confirm circuit breakers haven’t turned off and that your HVAC unit isn’t experiencing error codes.

“Cool On” or “Heat On” is Flickering

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

Then, check it’s signaling the right system to run. This is usually shown by “cool on,” “heat on” or a picture.

If this set of words or the illustration is pulsing, your thermostat is in a five-minute delay state. This feature stops your unit from damaging short cycling. This may take place 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 303-647-5749 for assistance.
  • 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. Finalize these settings so scheduling can take place.
  • 173—Thermostat temperature sensor error. Contact Lyric technical support at 800-633-3991.
  • 175—AC power restored. No action necessary.
  • 181/182—Replace air filter. Clear the monitor by hitting “dismiss” after installing a clean filter.
  • 184—Install a new humidifier pad. Clear the screen by tapping “dismiss” after putting in a new pad filter.
  • 185—Put in a new dehumidifier filter. Clear the thermostat by hitting “dismiss” after putting in a fresh filter.
  • 187—Rinse or install a new ventilator filter. Clear the monitor by touching “dismiss” after putting in a new filter.
  • 188/189—Get a new UV bulb. Call Service Experts Heating & Air Conditioning at 303-647-5749 for assistance.
  • 210—Register online for outside temperature. Get the Lyric app to complete this step and ensure accurate thermostat operation.
  • 388—Register online for remote access and exterior temperature. Get the Lyric app to finish this step and ensure correct 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 set. Use 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 needs service. Contact Service Experts Heating & Air Conditioning at 303-647-5749 for assistance.
  • 168—Wi-Fi radio error. Contact Service Experts Heating & Air Conditioning at 303-647-5749 for support.
  • 170—Internal memory error. Call Service Experts Heating & Air Conditioning at 303-647-5749 for help.
  • 171—Set date and time. Finish these settings so scheduling can operate.
  • 173—Thermostat temperature sensor error. Contact Service Experts Heating & Air Conditioning at 303-647-5749 for assistance.
  • 175—AC power restored. No action required.
  • 177—Indoor temperature sensor error. Call Service Experts Heating & Air Conditioning at 303-647-5749 for support.
  • 178—Outdoor temperature sensor error. Contact Service Experts Heating & Air Conditioning at 303-647-5749 for help.
  • 181/182—Get a new air filter. Clear the screen by hitting “dismiss” after putting in a fresh filter.
  • 183—Wash humidifier tank and install a new water filter. Clear the screen by tapping “dismiss” after completing these steps.
  • 184—Replace humidifier pad. Clear the monitor by tapping “dismiss” after getting a new pad filter.
  • 185—Install a new dehumidifier filter. Clear the monitor by tapping “dismiss” after putting in a fresh filter.
  • 186—Wash ventilator core. Clear the thermostat by touching “dismiss” after doing this task.
  • 187—Rinse or install a new ventilator filter. Clear the monitor by touching “dismiss” after installing a new filter.
  • 188/189—Add a new UV bulb. Reach Service Experts Heating & Air Conditioning at 303-647-5749 for assistance.
  • 210—Register online for outside temperature. Get the Lyric app to complete this step and ensure correct 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 pick new Wi-Fi network.
  • 508—Wi-Fi not set up. Download the Lyric app and follow the steps to connect your thermostat.

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

Our Experts are Ready to Provide Support

If you’re still experiencing issues after working through the troubleshooting list, our professionals are ready to help. Call us at 303-647-5749 and we’ll come to your house rapidly to figure out the malfunction.

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

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