How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the top thermostat brands, and we proudly install them on a regular basis in Pierre. They’re durable and reliable. In addition, Honeywell is constantly advancing its technology, resulting in more features for your home.

However, each thermostat can have problems from time to time. As a result, we’ve compiled this valuable guidebook to go over troubleshooting. While Honeywell thermostat problems are rare, they do occur. 

While you can usually repair the majority of thermostat issues on your own, they often call for Expert support. Our heating and cooling professionals are ready to assist you when you need us. We’re just a call away at 605-223-0307.

Let’s get started with the process by figuring out what model of thermostat your house has.

What Model of Thermostat Do I Have?

There are three types of thermostats:

  • Manual—This is the classic dial-shaped thermostat. You won’t have error codes with this type, but it’s also the least efficient for saving on heating and cooling costs.
  • Programmable—This thermostat features a digital screen and arrows you use to set your desired temperature. You can also choose daily programs to decrease the temperature when you’re at work and set it higher when you return.
  • Smart—You won’t have to schedule any programs on this thermostat, as it adjusts to your routine. It instinctively changes the temperature when you or family members are out and about to help you save on utility bills. You can also adjust the temperature anywhere using your phone or other Wi-Fi-enabled device. 

As you’re aware most technologically advanced solutions, there are regular glitches that can happen. The majority of of these problems don’t require pro help and are easy to solve on your own.

Common Honeywell Thermostat Issues

Every thermostat has an exclusive set of codes assigned to the malfunctions that occur.

Think how uncomplicated it can be to fix a computer by restarting it. In most cases, troubleshooting a thermostat can be just as uncomplicated.

Here is a guide to the most common Honeywell thermostat errors. These involve the following programmable thermostats:

Display is Blank

If the display is blank on your programmable thermostat, you might need to put in new batteries. If that doesn’t solve the trouble 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. Verify the switch near the indoor unit is switched “on”.

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

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

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

Heating and Cooling System Won’t Turn On

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

In the summer, verify you schedule the thermostat below the room temperature. When it’s cold, verify it’s higher. This sounds goofy, but we’ve seen it occur lots of times.

Make sure the power switch by your indoor unit is in the “on” position. You should also check the cabinet doors or panels are secure on your furnace cabinet or air handler. An open panel can trip the safety switch, diverting power to the system.

Heating or cooling still won’t turn on? Make sure circuit breakers haven’t turned off and that your HVAC system isn’t showing error codes.

“Cool On” or “Heat On” is Flickering

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

Then, make sure it’s telling the appropriate unit to run. This is often indicated by “cool on,” “heat on” or an icon.

If these words or the icon is pulsing, your thermostat is in a five-minute delay status. This setting stops your system from damaging 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 needs service. Call Peitz Service Experts at 605-223-0307 for assistance.
  • 168—Wi-Fi radio error. Call 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 occur.
  • 173—Thermostat temperature sensor error. Call Lyric technical support at 800-633-3991.
  • 175—AC power restored. No action needed.
  • 181/182—Replace air filter. Clear the screen by touching “dismiss” after putting in a fresh filter.
  • 184—Put in a new humidifier pad. Clear the monitor by touching “dismiss” after installing a new pad filter.
  • 185—Replace dehumidifier filter. Clear the display by hitting “dismiss” after adding a fresh filter.
  • 187—Wash or install a new ventilator filter. Clear the thermostat by touching “dismiss” after installing a fresh filter.
  • 188/189—Replace UV bulb. Ring Peitz Service Experts at 605-223-0307 for assistance.
  • 210—Register online for outdoor temperature. Get the Lyric app to do this step and ensure proper thermostat operation.
  • 388—Register online for remote access and exterior temperature. Get the Lyric app to finish this step and ensure proper thermostat operation.
  • 399—No Internet. Verify 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. Download the Lyric app and follow the process to connect your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump requires service. Call Peitz Service Experts at 605-223-0307 for assistance.
  • 168—Wi-Fi radio error. Call Peitz Service Experts at 605-223-0307 for assistance.
  • 170—Internal memory error. Contact Peitz Service Experts at 605-223-0307 for assistance.
  • 171—Set date and time. Complete these settings so scheduling can operate.
  • 173—Thermostat temperature sensor error. Call Peitz Service Experts at 605-223-0307 for assistance.
  • 175—AC power restored. No action required.
  • 177—Indoor temperature sensor error. Contact Peitz Service Experts at 605-223-0307 for assistance.
  • 178—Outdoor temperature sensor error. Contact Peitz Service Experts at 605-223-0307 for assistance.
  • 181/182—Install a new air filter. Clear the screen by touching “dismiss” after installing a clean filter.
  • 183—Wash humidifier tank and replace water filter. Clear the thermostat by tapping “dismiss” after completing these procedures.
  • 184—Install a new humidifier pad. Clear the monitor by tapping “dismiss” after installing pad filter.
  • 185—Replace dehumidifier filter. Clear the monitor by touching “dismiss” after adding a clean filter.
  • 186—Rinse ventilator core. Clear the screen by tapping “dismiss” after doing this task.
  • 187—Wash or get a new ventilator filter. Clear the screen by tapping “dismiss” after getting a new filter.
  • 188/189—Install a new UV bulb. Contact Peitz Service Experts at 605-223-0307 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 exterior temperature. Download the Lyric app to finish 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 choose new Wi-Fi network.
  • 508—Wi-Fi not set up. Use the Lyric app and follow the process to connect your thermostat.

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

Our Experts are Available to Provide Assistance

If you’re still running into problems after trying the troubleshooting process, our pros are here to assist you. Call us at 605-223-0307 and we’ll arrive rapidly to figure out the problem.

If you use an older thermostat, right now is a good time to consider a new thermostat. Thermostat technology has advanced over the last few years. Ask us for more information on how smart thermostats can make your house comfier while helping save on utility bills all year.

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