How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the leading thermostat manufacturers, and we proudly install them on a regular basis in Gaithersburg. They’re sturdy and trustworthy. Plus, Honeywell is frequently advancing its technology, resulting in more features for your house.

Nevertheless, every thermostat can have errors from time to time. Due to this, we’ve prepared this valuable guide to run through troubleshooting.

While you can typically solve most thermostat problems alone, they sometimes need Expert support. Our heating and cooling pros are here to support you when you need us. We’re merely a call away at 301-476-4577.

Let’s get started with 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 older dial-shaped thermostat. You won’t experience error codes with this kind, but it’s also the least efficient for lowering utility bills.
  • Programmable—This thermostat has a digital screen and arrows you use to determine your desired temperature. You can also set daily programs to decrease the temperature when you’re gone and raise it when you come home.
  • Smart—You won’t have to schedule any programs on this thermostat, as it learns your routine. It intuitively raises and lowers the temperature when you or family members are out and about to help you save on utility bills. You can also change the temperature anywhere on your phone or other Wi-Fi-enabled device. 

As you’re aware the majority of technologically advanced solutions, there are regular glitches that may happen. Many of these issues don’t require professional help and are uncomplicated enough to repair alone.

Common Honeywell Thermostat Issues

Every thermostat has a special group of codes that correspond to the issues that happen.

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

Here are some of the most encountered Honeywell thermostat issues. These include the following programmable thermostats:

Display is Blank

If the monitor is clear on your programmable thermostat, you might need to replace the batteries. If that doesn’t fix the problem or you use a smart thermostat, there might be a wiring issue.

Next, you should check the power is enabled for your furnace or air handler. Confirm the switch near the indoor equipment is switched “on”.

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

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

Infrequently, a clear screen could mean you need to install a new thermostat.

Heating and Cooling Unit Won’t Start

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

When it’s hot, confirm you put the thermostat beneath the ambient temperature. When it’s cold, make sure it’s higher. This sounds goofy, but we’ve seen it occur many times.

Make sure the power switch close to your indoor system 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, cutting off power to the equipment.

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

“Cool On” or “Heat On” is Flashing

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

Then, ensure it’s signaling the right system to turn on. This is usually shown by “cool on,” “heat on” or an icon.

If this phrase or the picture is blinking, your thermostat is in a five-minute delay mode. This mode keeps your unit from harmful short cycling. This could happen if you lose power.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump requires service. Call Parker Pearce Service Experts at 301-476-4577 for assistance.
  • 168—Wi-Fi radio error. Contact 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 run.
  • 173—Thermostat temperature sensor error. Reach Lyric technical support at 800-633-3991.
  • 175—AC power resumed. No action needed.
  • 181/182—Replace air filter. Clear the display by hitting “dismiss” after installing a fresh filter.
  • 184—Replace humidifier pad. Clear the screen by hitting “dismiss” after installing a fresh pad filter.
  • 185—Replace dehumidifier filter. Clear the thermostat by hitting “dismiss” after adding a new filter.
  • 187—Rinse or replace ventilator filter. Clear the display by touching “dismiss” after installing a new filter.
  • 188/189—Get a new UV bulb. Contact Parker Pearce Service Experts at 301-476-4577 for assistance.
  • 210—Register online for outdoor temperature. Use the Lyric app to finish this step and ensure correct thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Download the Lyric app to complete 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 select new Wi-Fi network.
  • 508—Wi-Fi not configured. Use the Lyric app and follow the process to connect your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump must be serviced service. Call Parker Pearce Service Experts at 301-476-4577 for help.
  • 168—Wi-Fi radio error. Call Parker Pearce Service Experts at 301-476-4577 for help.
  • 170—Internal memory error. Reach Parker Pearce Service Experts at 301-476-4577 for support.
  • 171—Set date and time. Finish these settings so scheduling can work.
  • 173—Thermostat temperature sensor error. Contact Parker Pearce Service Experts at 301-476-4577 for support.
  • 175—AC power resumed. No action needed.
  • 177—Indoor temperature sensor error. Contact Parker Pearce Service Experts at 301-476-4577 for assistance.
  • 178—Outdoor temperature sensor error. Reach Parker Pearce Service Experts at 301-476-4577 for support.
  • 181/182—Install a new air filter. Clear the monitor by tapping “dismiss” after putting in a new filter.
  • 183—Clean humidifier tank and replace water filter. Clear the thermostat by hitting “dismiss” after completing these procedures.
  • 184—Get a new humidifier pad. Clear the thermostat by tapping “dismiss” after installing pad filter.
  • 185—Replace dehumidifier filter. Clear the display by tapping “dismiss” after adding a clean filter.
  • 186—Clean ventilator core. Clear the screen by tapping “dismiss” after doing this task.
  • 187—Rinse or get a new ventilator filter. Clear the monitor by touching “dismiss” after installing a new filter.
  • 188/189—Install a new UV bulb. Reach Parker Pearce Service Experts at 301-476-4577 for help.
  • 210—Register online for outdoor temperature. Use the Lyric app to do this step and ensure accurate thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Use the Lyric app to do 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 pick new Wi-Fi network.
  • 508—Wi-Fi not configured. Get the Lyric app and follow the process to connect your thermostat.

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

Our Experts are Ready to Help

If you’re still experiencing troubles after trying the troubleshooting list, our professionals are here to help. Call us at 301-476-4577 and we’ll come to your house as fast as we can to determine the problem.

If you have an older thermostat, now is a fantastic time to consider a new device. Thermostat technology has gotten better over the last few years. Ask us for more information on how smart thermostats can make your home more convenient while helping save on energy bills all year.

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