How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the top thermostat brands, and we proudly install them on a regular basis in Longmont. They’re long-lasting and trustworthy. Also, Honeywell is frequently improving its technology, resulting in more features for your home.

Still, each thermostat can run into problems every now and then. Due to this, we’ve compiled this useful guidebook to go over troubleshooting.

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

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

What Model of Thermostat Do I Have?

There are three models of thermostats:

  • Manual—This is the classic dial-shaped thermostat. You won’t experience error codes with this kind, but it’s also the least efficient for reducing energy costs.
  • Programmable—This thermostat has a digital screen and arrows you touch to set your desired temperature. You can also set daily programs to decrease the temperature when you’re away and raise it when you come home.
  • Smart—You won’t have to set any programs on this thermostat, because it learns your day. It intuitively changes the temperature when you or loved ones are gone to help you save on energy bills. You can also adjust the temperature anywhere on your phone or other Wi-Fi-enabled device. 

As you’re aware many technologically advanced things, there are regular malfunctions that can take place. Most of these problems don’t call for pro support and are simple to fix alone.

Common Honeywell Thermostat Issues

Every thermostat has an exclusive set of codes matching the troubles that occur.

Think how simple it can be to fix a computer by restarting it. In many instances, diagnosing 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 screen is clear on your programmable thermostat, you might need to put in new batteries. If that doesn’t fix the trouble or you use 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 by the indoor unit is switched “up”.

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

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

While it’s less common, a blank display may indicate you should buy a new thermostat.

HVAC Equipment Won’t Work

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

In the summer, confirm you put the thermostat beneath the room temperature. In the winter, verify it’s higher. This sounds goofy, but we’ve seen it take place lots of times.

Confirm the power switch by your indoor equipment is in the “on” position. You should also make sure the cabinet doors or panels are tight on your furnace cabinet or air handler. An unsecured panel can trip the safety switch, cutting off power to the equipment.

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

“Cool On” or “Heat On” is Blinking

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

Then, check it’s telling the right system to run. This is usually shown by “cool on,” “heat on” or an illustration.

If this set of words or the illustration is blinking, your thermostat is in a five-minute delay status. This feature keeps your equipment from damaging short cycling. This could take place if you lose electricity.

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. Reach Lyric technical support at 800-633-3991.
  • 171—Set date and time. Finish these settings so scheduling can occur.
  • 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 adding a new pad filter.
  • 185—Put in a new dehumidifier filter. Clear the thermostat by tapping “dismiss” after adding a fresh filter.
  • 187—Wash or install a new ventilator filter. Clear the screen by touching “dismiss” after adding 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 exterior temperature. Get the Lyric app to complete this step and ensure correct 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. Verify 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. 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 support.
  • 171—Set date and time. Finalize these settings so scheduling can operate.
  • 173—Thermostat temperature sensor error. Reach Service Experts Heating & Air Conditioning at 303-647-5749 for assistance.
  • 175—AC power reconnected. 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—Install a new air filter. Clear the screen by hitting “dismiss” after putting in a clean 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 hitting “dismiss” after adding a new pad filter.
  • 185—Get a new dehumidifier filter. Clear the monitor by hitting “dismiss” after adding a fresh filter.
  • 186—Rinse ventilator core. Clear the thermostat by touching “dismiss” after doing this task.
  • 187—Wash or get a new ventilator filter. Clear the monitor by touching “dismiss” after installing a new filter.
  • 188/189—Add a new UV bulb. Get in touch with Service Experts Heating & Air Conditioning at 303-647-5749 for assistance.
  • 210—Register online for exterior temperature. Use the Lyric app to complete 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 accurate thermostat operation.
  • 399—No Internet. Verify 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 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 running into troubles after working through the troubleshooting process, our professionals are ready to help. Call us at 303-647-5749 and we’ll arrive as fast as we can to figure out the issue.

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

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