How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the top thermostat brands, and we proudly install them on a regular basis in Livermore. They’re durable and dependable. Also, Honeywell is regularly enhancing its technology, bringing more features for your household.

However, each thermostat can experience errors from time to time. As a result, we’ve compiled this useful handbook to go over troubleshooting.

While you can usually fix the majority of thermostat troubles alone, they often call for Expert assistance. Our home comfort pros are ready to assist you when you need us. We’re merely a call away at 925-364-5427.

Let’s get started with the process by finding out what type of thermostat your residence has.

What Type 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 saving on energy bills.
  • Programmable—This thermostat has a digital screen and arrows you touch to determine your desired temperature. You can also use daily programs to lower the temperature when you’re gone and raise it when you get back.
  • Smart—You won’t have to set any programs on this thermostat, because it picks up on your schedule. It instinctively changes the temperature when you or other household members are gone 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 many technologically advanced things, there are several problems that can happen. Most of these situations don’t require professional assistance and are uncomplicated enough to repair on your own.

Common Honeywell Thermostat Problems

Every thermostat has a special group of codes assigned to the troubles that happen.

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

Here are some of 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 replace the batteries. If that doesn’t fix the problem or you rely on a smart thermostat, there might be a wiring problem.

Next, you should check the power is enabled for your furnace or air handler. Make sure the switch near the indoor equipment is in the “on” position.

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

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

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

Comfort Unit Won’t Start

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

When it’s hot, confirm you schedule the thermostat beneath the current temperature. When it’s cold, make sure it’s higher. This sounds silly, but we’ve seen it take place a lot of times.

Make sure the power switch near your indoor unit is in the “on” position. You should also comfirm the cabinet doors or panels are secure on your furnace cabinet or air handler. An open panel can activate the safety switch, cutting off power to the system.

System still won’t run? Make sure circuit breakers haven’t turned off and that your HVAC equipment isn’t displaying error codes.

“Cool On” or “Heat On” is Blinking

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

Then, ensure it’s signaling the correct equipment to turn on. This is typically indicated by “cool on,” “heat on” or an icon.

If this set of words or the picture is blinking, your thermostat is in a five-minute delay mode. This feature protects your system from harmful short cycling. This could occur 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 925-364-5427 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. Complete 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 needed.
  • 181/182—Install a new air filter. Clear the thermostat by touching “dismiss” after installing a fresh filter.
  • 184—Install a new humidifier pad. Clear the display by tapping “dismiss” after putting in a fresh pad filter.
  • 185—Install a new dehumidifier filter. Clear the display by touching “dismiss” after putting in a new filter.
  • 187—Clean or install a new ventilator filter. Clear the screen by hitting “dismiss” after installing a clean filter.
  • 188/189—Install a new UV bulb. Contact Service Experts Heating & Air Conditioning at 925-364-5427 for help.
  • 210—Register online for outside temperature. Use the Lyric app to finish this step and ensure proper thermostat operation.
  • 388—Register online for remote access and exterior temperature. Use 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 up. Get the Lyric app and follow the procedure to link your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump must be serviced service. Reach Service Experts Heating & Air Conditioning at 925-364-5427 for help.
  • 168—Wi-Fi radio error. Reach Service Experts Heating & Air Conditioning at 925-364-5427 for help.
  • 170—Internal memory error. Contact Service Experts Heating & Air Conditioning at 925-364-5427 for assistance.
  • 171—Set date and time. Complete these settings so scheduling can work.
  • 173—Thermostat temperature sensor error. Contact Service Experts Heating & Air Conditioning at 925-364-5427 for support.
  • 175—AC power resumed. No action needed.
  • 177—Indoor temperature sensor error. Reach Service Experts Heating & Air Conditioning at 925-364-5427 for help.
  • 178—Outdoor temperature sensor error. Contact Service Experts Heating & Air Conditioning at 925-364-5427 for help.
  • 181/182—Install a new air filter. Clear the thermostat by tapping “dismiss” after putting in a fresh 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 screen by hitting “dismiss” after installing pad filter.
  • 185—Install a new dehumidifier filter. Clear the monitor by touching “dismiss” after adding a fresh filter.
  • 186—Rinse ventilator core. Clear the screen by tapping “dismiss” after doing this task.
  • 187—Rinse or install a new ventilator filter. Clear the display by touching “dismiss” after buying a new filter.
  • 188/189—Add a new UV bulb. Contact Service Experts Heating & Air Conditioning at 925-364-5427 for support.
  • 210—Register online for exterior temperature. Get the Lyric app to do 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 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 up. Get the Lyric app and follow the process to connect your thermostat.

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

Our Experts are Ready to Provide Assistance

If you’re still running into problems after trying the troubleshooting list, our Experts are here to help. Give us a call at 925-364-5427 and we’ll come to your house quickly to determine the problem.

If you rely on an older thermostat, right now is a fantastic time to think about a replacement. Thermostat technology has gotten better lately Ask us for more details on how smart thermostats can make your residence more comfortable while helping save on utility bills all year.

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