How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the best thermostat producers, and we proudly install them on a frequent basis in Jackson. They’re long-lasting and reliable. In addition, Honeywell is constantly updating its technology, resulting in more features for your household.

Still, all thermostats can run into errors every now and then. Due to this, we’ve prepared this valuable guidebook to run through troubleshooting.

While you can usually repair many thermostat problems alone, they often require Expert support. Our home comfort pros are available to support you when you need us. We’re just a call away at 601-852-3105.

Let’s begin the process by determining what kind of thermostat your residence has.

What Model of Thermostat Do I Have?

There are three kinds of thermostats:

  • Manual—This is the typical dial-shaped thermostat. You won’t experience error codes with this type, but it’s also the least efficient for reducing energy costs.
  • Programmable—This thermostat features a digital screen and arrows you press to determine your desired temperature. You can also choose daily programs to decrease the temperature when you’re gone and set it higher when you return.
  • Smart—You won’t have to set any programs on this thermostat, since it adjusts to your day. It automatically changes the temperature when you or loved ones are away to help you save on energy expenses. You can also raise or lower the temperature anywhere using your phone or other Wi-Fi-enabled device. 

As you know many technologically advanced products, there are regular malfunctions that can occur. The majority of of these troubles don’t call for Expert assistance and are easy to repair by yourself.

Common Honeywell Thermostat Issues

Every thermostat has a unique kind of codes that correspond to the glitches that take place.

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

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

Display is Blank

If the screen is clear on your programmable thermostat, you could need to install new batteries. If that doesn’t solve the problem or you have a smart thermostat, there may be a wiring issue.

Next, you should make sure the power is on for your furnace or air handler. Verify the switch by the indoor equipment is switched “up”.

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

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

Less frequently, a blank display could mean you will need to buy a new thermostat.

HVAC System Won’t Run

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

In the summer, verify you schedule the thermostat lower than the ambient temperature. When it’s cool, verify it’s higher. This sounds goofy, but we’ve seen it take place a lot of times.

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

System still won’t start? Verify circuit breakers haven’t tripped and that your HVAC unit isn’t showing error codes.

“Cool On” or “Heat On” is Flickering

First, confirm your thermostat is set to “cool” or “heat.”

Then, ensure it’s telling the right equipment to turn on. This is often demonstrated by “cool on,” “heat on” or a picture.

If this set of words or the illustration is pulsing, your thermostat is in a five-minute delay state. This feature protects your equipment from bad short cycling. This could take place if you lose power.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump requires service. Call Comfortech Service Experts at 601-852-3105 for help.
  • 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. Complete these settings so scheduling can take place.
  • 173—Thermostat temperature sensor error. Reach Lyric technical support at 800-633-3991.
  • 175—AC power restored. No action necessary.
  • 181/182—Put in a new air filter. Clear the monitor by touching “dismiss” after adding a clean filter.
  • 184—Put in a new humidifier pad. Clear the display by hitting “dismiss” after adding a new pad filter.
  • 185—Replace dehumidifier filter. Clear the monitor by touching “dismiss” after installing a new filter.
  • 187—Wash or install a new ventilator filter. Clear the display by tapping “dismiss” after adding a fresh filter.
  • 188/189—Get a new UV bulb. Contact Comfortech Service Experts at 601-852-3105 for help.
  • 210—Register online for outdoor temperature. Download the Lyric app to complete this step and ensure accurate thermostat operation.
  • 388—Register online for remote access and exterior temperature. Get the Lyric app to finish this step and ensure accurate 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 set up. Use the Lyric app and follow the process to configure your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump must be serviced service. Contact Comfortech Service Experts at 601-852-3105 for assistance.
  • 168—Wi-Fi radio error. Call Comfortech Service Experts at 601-852-3105 for assistance.
  • 170—Internal memory error. Call Comfortech Service Experts at 601-852-3105 for assistance.
  • 171—Set date and time. Finish these settings so scheduling can operate.
  • 173—Thermostat temperature sensor error. Call Comfortech Service Experts at 601-852-3105 for help.
  • 175—AC power restored. No action required.
  • 177—Indoor temperature sensor error. Call Comfortech Service Experts at 601-852-3105 for support.
  • 178—Outdoor temperature sensor error. Reach Comfortech Service Experts at 601-852-3105 for assistance.
  • 181/182—Install a new air filter. Clear the screen by hitting “dismiss” after installing a new 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 monitor by tapping “dismiss” after installing pad filter.
  • 185—Get a new dehumidifier filter. Clear the display by tapping “dismiss” after installing a fresh filter.
  • 186—Clean ventilator core. Clear the display by hitting “dismiss” after completing this task.
  • 187—Rinse or install a new ventilator filter. Clear the screen by tapping “dismiss” after installing a new filter.
  • 188/189—Get a new UV bulb. Contact Comfortech Service Experts at 601-852-3105 for support.
  • 210—Register online for exterior temperature. Use the Lyric app to complete this step and ensure correct thermostat operation.
  • 388—Register online for remote access and outside 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 pick new Wi-Fi network.
  • 508—Wi-Fi not connected. Download the Lyric app and follow the steps to connect your thermostat.

For more specifics, view 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 Experts are ready to support you. Call us at 601-852-3105 and we’ll come to your house rapidly to determine the problem.

If you have an aging thermostat, now is a great time to think about a replacement. Thermostat technology has gotten better over the last few years. Ask us for more details on how smart thermostats can make your residence more convenient while helping save on utility bills all year.

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