How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the top thermostat manufacturers, and we proudly install them on a regular basis in Fort Wayne. They’re sturdy and trustworthy. Also, Honeywell is constantly advancing its technology, bringing more features for your house.

However, all thermostats can experience troubles at one time or another. Due to this, we’ve compiled this useful manual to run through troubleshooting.

While you can usually fix most thermostat troubles alone, they often require Expert help. Our HVAC professionals are available to help when you need us. We’re merely a call away at 260-557-1275.

Let’s start the process by finding out what kind of thermostat your home 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 type, but it’s also the least efficient for reducing energy bills.
  • Programmable—This thermostat includes a digital screen and arrows you touch to determine your desired temperature. You can also choose daily programs to decrease the temperature when you’re away and raise it when you get back.
  • Smart—You won’t have to make any programs on this thermostat, as it adjusts to your schedule. It automatically adjusts the temperature when you or other household members are gone to help you save on energy bills. You can also adjust the temperature anywhere on your phone or other Wi-Fi-enabled device. 

As you know many technologically advanced solutions, there are common problems that might happen. Many of these situations don’t call for pro assistance and are uncomplicated enough to solve alone.

Common Honeywell Thermostat Problems

Each thermostat has a unique group of codes assigned to the issues that occur.

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

Here is a guide to the most encountered Honeywell thermostat problems. These are applicable to the following programmable thermostats:

Display is Blank

If the monitor is empty on your programmable thermostat, you may need to get new batteries. If that doesn’t take care of the issue or you use a smart thermostat, there may be a wiring issue.

Next, you should check the power is enabled for your furnace or air handler. Confirm the switch by the indoor unit is in the “on” position.

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

A loose panel may trigger the safety switch, which disconnects power to the equipment.

Infrequently, an empty display could signify you should get a new thermostat.

Comfort Equipment Won’t Run

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

During warm weather, verify you put the thermostat beneath the ambient temperature. When it’s cold, confirm it’s higher. This sounds absurd, but we’ve seen it happen a lot of times.

Make sure the power switch near your indoor equipment is in the “on” position. You should also check the cabinet doors or panels are tight on your furnace cabinet or air handler. A loose panel can trip the safety switch, cutting off power to the system.

Unit 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 Blinking

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

Then, verify it’s telling the right system to start. This is often demonstrated by “cool on,” “heat on” or a picture.

If this set of words or the picture is pulsing, your thermostat is in a five-minute delay status. This feature protects your unit 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 must be serviced. Call Rolf Griffin Service Experts at 260-557-1275 for support.
  • 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. Complete these settings so scheduling can run.
  • 173—Thermostat temperature sensor error. Contact Lyric technical support at 800-633-3991.
  • 175—AC power resumed. No action necessary.
  • 181/182—Put in a new air filter. Clear the monitor by hitting “dismiss” after adding a new filter.
  • 184—Put in a new humidifier pad. Clear the screen by hitting “dismiss” after adding a fresh pad filter.
  • 185—Install a new dehumidifier filter. Clear the monitor by touching “dismiss” after putting in a fresh filter.
  • 187—Clean or install a new ventilator filter. Clear the screen by touching “dismiss” after installing a fresh filter.
  • 188/189—Install a new UV bulb. Contact Rolf Griffin Service Experts at 260-557-1275 for help.
  • 210—Register online for exterior temperature. Use the Lyric app to finish this step and ensure proper thermostat operation.
  • 388—Register online for remote access and outside temperature. Use the Lyric app to do 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 configured. Get the Lyric app and follow the steps to link your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump must be serviced service. Reach Rolf Griffin Service Experts at 260-557-1275 for help.
  • 168—Wi-Fi radio error. Contact Rolf Griffin Service Experts at 260-557-1275 for help.
  • 170—Internal memory error. Call Rolf Griffin Service Experts at 260-557-1275 for help.
  • 171—Set date and time. Finalize these settings so scheduling can work.
  • 173—Thermostat temperature sensor error. Reach Rolf Griffin Service Experts at 260-557-1275 for support.
  • 175—AC power reconnected. No action needed.
  • 177—Indoor temperature sensor error. Reach Rolf Griffin Service Experts at 260-557-1275 for help.
  • 178—Outdoor temperature sensor error. Call Rolf Griffin Service Experts at 260-557-1275 for assistance.
  • 181/182—Install a new air filter. Clear the display by touching “dismiss” after adding a clean filter.
  • 183—Rinse humidifier tank and install a new water filter. Clear the thermostat by hitting “dismiss” after finishing these tasks.
  • 184—Get a new humidifier pad. Clear the screen by tapping “dismiss” after installing pad filter.
  • 185—Install a new dehumidifier filter. Clear the screen by tapping “dismiss” after installing a fresh filter.
  • 186—Clean ventilator core. Clear the monitor by touching “dismiss” after completing this task.
  • 187—Wash or get a new ventilator filter. Clear the screen by hitting “dismiss” after installing a new filter.
  • 188/189—Add a new UV bulb. Reach Rolf Griffin Service Experts at 260-557-1275 for assistance.
  • 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. 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 set up. Download the Lyric app and follow the process to connect your thermostat.

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

Our Experts are Available to Provide Support

If you’re still having troubles after working through the troubleshooting list, our professionals are ready to assist you. Call us at 260-557-1275 and we’ll arrive quickly to figure out the issue.

If you use an older thermostat, right now is a good time to think about a replacement. Thermostat technology has come a long way lately Ask us for more information on how smart thermostats can make your residence comfier while helping save on heating and cooling expenses throughout the year.

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