How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the best thermostat producers, and we proudly install them on a regular basis in San Antonio. They’re durable and trustworthy. Also, Honeywell is constantly updating its technology, bringing more features for your home.

Still, each thermostat can have problems now and again. As a result, we’ve put together this informative manual to walk you through troubleshooting. While Honeywell thermostat problems are rare, they do pop up. 

While you can typically solve the majority of thermostat troubles alone, they often require Expert assistance. Our home comfort pros are available to help when you need us. We’re merely a call away at 210-570-9705.

Let’s begin the process by finding out what model of thermostat your home 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 run into error codes with this one, but it’s also the least efficient for saving on energy expenses.
  • Programmable—This thermostat has a digital screen and arrows you touch to determine your desired temperature. You can also set daily programs to decrease the temperature when you’re at work and set it higher when you come home.
  • Smart—You won’t have to set any programs on this thermostat, since it learns your day. It instinctively changes the temperature when you or family members are gone to help you save on heating and cooling costs. You can also raise or lower the temperature anywhere via your phone or other Wi-Fi-enabled device. 

As you know many technologically advanced things, there are common glitches that may happen. Most of these problems don’t need pro assistance and are simple to fix alone.

Common Honeywell Thermostat Troubles

Each thermostat has a unique set of codes that correspond to the issues that occur.

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

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

Display is Blank

If the monitor is empty on your programmable thermostat, you could need to put in new batteries. If that doesn’t fix the malfunction or you have a smart thermostat, there might 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 system is in the “on” position.

Also, you should make sure all furnace cabinet or air handler doors/panels are tightly secured.

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

Less frequently, a blank monitor may signify you will need to buy a new thermostat.

Heating and Cooling Equipment Won’t Start

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

During warm weather, make sure you schedule the thermostat below the room temperature. When it’s cool, make sure it’s higher. This sounds silly, but we’ve seen it take place many times.

Make sure 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. A loose panel can trip the safety switch, diverting power to the system.

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

“Cool On” or “Heat On” is Blinking

To start, check your thermostat is set to “cool” or “heat.”

Then, make sure it’s telling the correct unit to turn on. This is typically demonstrated by “cool on,” “heat on” or a picture.

If this phrase or the picture is blinking, your thermostat is in a five-minute delay state. This mode protects your system from harmful short cycling. This can take place if you lose power.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump requires service. Call San Antonio Air Service Experts at 210-570-9705 for assistance.
  • 168—Wi-Fi radio error. Contact Lyric technical support at 800-633-3991. 170—Internal memory error. Call Lyric technical support at 800-633-3991.
  • 171—Set date and time. Finish 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 required.
  • 181/182—Install a new air filter. Clear the thermostat by touching “dismiss” after installing a clean filter.
  • 184—Install a new humidifier pad. Clear the monitor by tapping “dismiss” after installing a clean pad filter.
  • 185—Replace dehumidifier filter. Clear the monitor by touching “dismiss” after adding a clean filter.
  • 187—Rinse or put in a new ventilator filter. Clear the thermostat by touching “dismiss” after putting in a fresh filter.
  • 188/189—Replace UV bulb. Call San Antonio Air Service Experts at 210-570-9705 for support.
  • 210—Register online for outdoor 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. 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. Use the Lyric app and follow the steps to configure your thermostat.

For more details, check this thermostat’s user manual.

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump requires service. Call San Antonio Air Service Experts at 210-570-9705 for support.
  • 168—Wi-Fi radio error. Reach San Antonio Air Service Experts at 210-570-9705 for help.
  • 170—Internal memory error. Contact San Antonio Air Service Experts at 210-570-9705 for assistance.
  • 171—Set date and time. Complete these settings so scheduling can operate.
  • 173—Thermostat temperature sensor error. Call San Antonio Air Service Experts at 210-570-9705 for support.
  • 175—AC power resumed. No action necessary.
  • 177—Indoor temperature sensor error. Call San Antonio Air Service Experts at 210-570-9705 for assistance.
  • 178—Outdoor temperature sensor error. Reach San Antonio Air Service Experts at 210-570-9705 for support.
  • 181/182—Replace air filter. Clear the thermostat by hitting “dismiss” after putting in a fresh filter.
  • 183—Wash humidifier tank and replace water filter. Clear the display by touching “dismiss” after finishing these procedures.
  • 184—Get a new humidifier pad. Clear the monitor by tapping “dismiss” after getting a new pad filter.
  • 185—Install a new dehumidifier filter. Clear the screen by touching “dismiss” after adding a clean filter.
  • 186—Wash ventilator core. Clear the monitor by tapping “dismiss” after finishing this task.
  • 187—Wash or get a new ventilator filter. Clear the display by touching “dismiss” after installing a new filter.
  • 188/189—Replace UV bulb. Get in touch with San Antonio Air Service Experts at 210-570-9705 for assistance.
  • 210—Register online for outside temperature. Get the Lyric app to complete this step and ensure proper thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Download 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 configured. 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 Available to Provide Support

If you’re still having problems after trying the troubleshooting steps, our pros are here to assist you. Reach us at 210-570-9705 and we’ll be out quickly to diagnose the issue.

If you use an older thermostat, now is a great time to consider a new thermostat. Thermostat technology has come a long way in recent years Ask us for more info on how smart thermostats can make your residence better while helping save on heating and cooling costs year-round.

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