How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the best thermostat producers, and we proudly install them on a frequent basis in North America. They’re durable and dependable. Also, Honeywell is constantly advancing its technology, offering more features for your house.

Nevertheless, every thermostat can have issues every now and then. As a result, we’ve compiled this informative manual to walk you through troubleshooting.

While you can usually fix most thermostat problems on your own, they sometimes need Expert help. Our HVAC professionals are here to support you when you need us. We’re just a call away at 866-397-3787.

Let’s begin the process by determining what model of thermostat your house has.

What Model of Thermostat Do I Have?

There are three kinds of thermostats:

  • Manual—This is the typical dial-shaped thermostat. You won’t experience error codes with this type, but it’s also the least efficient for saving on energy bills.
  • Programmable—This thermostat includes a digital screen and arrows you touch to choose your desired temperature. You can also set daily programs to decrease the temperature when you’re gone and increase it when you get back.
  • Smart—You won’t have to make any programs on this thermostat, as it learns your day. It intuitively changes the temperature when you or other household members are away to help you save on utility costs. You can also adjust the temperature anywhere via your phone or other Wi-Fi-enabled device. 

As you’re aware many technologically advanced products, there are common problems that may take place. Many of these troubles don’t require pro support and are easy to fix on your own.

Common Honeywell Thermostat Issues

All thermostats have an exclusive kind of codes matching the troubles that take place.

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

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

Display is Blank

If the screen is blank on your programmable thermostat, you may need to put in new batteries. If that doesn’t take care of the trouble or you have a smart thermostat, there could be a wiring issue.

Next, you should check the power is enabled for your furnace or air handler. Make sure the switch by the indoor unit is switched “up”.

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

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

Infrequently, a blank monitor may indicate you should buy a new thermostat.

HVAC Equipment Won’t Work

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

In the summer, verify you schedule the thermostat beneath the ambient temperature. When it’s cold, verify it’s higher. This sounds silly, but we’ve seen it occur a lot of times.

Confirm the power switch close to your indoor unit is in the “on” position. You should also check the cabinet doors or panels are tight on your furnace cabinet or air handler. An unsecured panel can activate the safety switch, diverting electricity to the system.

Equipment still won’t run? Verify circuit breakers haven’t flipped and that your HVAC system isn’t experiencing error codes.

“Cool On” or “Heat On” is Blinking

To begin, confirm your thermostat is set to “cool” or “heat.”

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

If these words or the icon is pulsing, your thermostat is in a five-minute delay state. This setting stops your equipment from damaging short cycling. This could happen if you lose power.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump must be serviced. Call Service Experts Heating & Air Conditioning at 866-397-3787 for assistance.
  • 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. Finalize these settings so scheduling can run.
  • 173—Thermostat temperature sensor error. Reach Lyric technical support at 800-633-3991.
  • 175—AC power resumed. No action required.
  • 181/182—Replace air filter. Clear the display by tapping “dismiss” after putting in a clean filter.
  • 184—Put in a new humidifier pad. Clear the display by tapping “dismiss” after installing a new pad filter.
  • 185—Put in a new dehumidifier filter. Clear the monitor by hitting “dismiss” after installing a new filter.
  • 187—Wash or put in a new ventilator filter. Clear the monitor by touching “dismiss” after adding a fresh filter.
  • 188/189—Replace UV bulb. Ring Service Experts Heating & Air Conditioning at 866-397-3787 for help.
  • 210—Register online for outdoor temperature. Download 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 accurate 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 configured. Download the Lyric app and follow the steps to link your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump needs service. Contact Service Experts Heating & Air Conditioning at 866-397-3787 for support.
  • 168—Wi-Fi radio error. Call Service Experts Heating & Air Conditioning at 866-397-3787 for support.
  • 170—Internal memory error. Contact Service Experts Heating & Air Conditioning at 866-397-3787 for help.
  • 171—Set date and time. Finalize these settings so scheduling can work.
  • 173—Thermostat temperature sensor error. Contact Service Experts Heating & Air Conditioning at 866-397-3787 for help.
  • 175—AC power restored. No action necessary.
  • 177—Indoor temperature sensor error. Call Service Experts Heating & Air Conditioning at 866-397-3787 for assistance.
  • 178—Outdoor temperature sensor error. Call Service Experts Heating & Air Conditioning at 866-397-3787 for support.
  • 181/182—Get a new air filter. Clear the screen by touching “dismiss” after putting in a clean filter.
  • 183—Wash humidifier tank and install a new water filter. Clear the monitor by hitting “dismiss” after doing these tasks.
  • 184—Replace humidifier pad. Clear the monitor by hitting “dismiss” after adding a new pad filter.
  • 185—Replace dehumidifier filter. Clear the monitor by hitting “dismiss” after putting in a clean filter.
  • 186—Clean ventilator core. Clear the monitor by hitting “dismiss” after doing this task.
  • 187—Rinse or install a new ventilator filter. Clear the monitor by hitting “dismiss” after installing a new filter.
  • 188/189—Add a new UV bulb. Get in touch with Service Experts Heating & Air Conditioning at 866-397-3787 for support.
  • 210—Register online for exterior temperature. Download the Lyric app to do this step and ensure correct thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Get the Lyric app to do 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 set up. Download the Lyric app and follow the steps to connect your thermostat.

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

Our Experts are Ready to Provide Support

If you’re still having issues after working through the troubleshooting list, our Experts are here to support you. Give us a call at 866-397-3787 and we’ll come to your house as fast as we can to determine the issue.

If you rely on an aging thermostat, now is a good time to consider a new device. Thermostat technology has come a long way lately Ask us for more information on how smart thermostats can make your house more comfortable while helping save on utility bills all year.

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