How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the leading thermostat manufacturers, and we proudly install them on a frequent basis in Boise. They’re long-lasting and reliable. Plus, Honeywell is frequently updating its technology, resulting in more features for your home.

Nevertheless, all thermostats can have errors occasionally. As a result, we’ve prepared this useful manual to walk you through troubleshooting.

While you can usually fix most thermostat issues by yourself, they often call for Expert help. Our home comfort professionals are ready to help when you need us. We’re just a call away at 208-488-4892.

Let’s get started with the process by determining what kind of thermostat your residence has.

What Type of Thermostat Do I Have?

There are three types of thermostats:

  • Manual—This is the typical dial-shaped thermostat. You won’t have error codes with this one, but it’s also the least efficient for reducing heating and cooling costs.
  • Programmable—This thermostat includes a digital screen and arrows you use to determine your desired temperature. You can also use daily programs to reduce the temperature when you’re gone and raise it when you return.
  • Smart—You won’t have to schedule any programs on this thermostat, because it learns your schedule. It instinctively adjusts the temperature when you or family members are away to help you save on heating and cooling expenses. You can also change the temperature anywhere via your phone or other Wi-Fi-enabled device. 

As you’re aware the majority of technologically advanced products, there are common glitches that may happen. The majority of of these issues don’t call for Expert help and are uncomplicated enough to solve by yourself.

Common Honeywell Thermostat Troubles

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

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

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

Display is Blank

If the screen is blank on your programmable thermostat, you might need to install new batteries. If that doesn’t take care of the trouble or you have a smart thermostat, there could be a wiring problem.

Next, you should make sure the power is flowing for your furnace or air handler. Confirm 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 securely secured.

A panel that isn’t tight may activate the safety switch, which cuts off power to the equipment.

Less frequently, a blank display could indicate you will need to install a new thermostat.

HVAC Unit Won’t Turn On

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

During warm weather, make sure you schedule the thermostat lower than the ambient temperature. In the winter, confirm it’s higher. This sounds absurd, but we’ve seen it take place lots 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 unsecured panel can activate the safety switch, cutting off electricity to the equipment.

Unit still won’t turn on? Confirm circuit breakers haven’t tripped and that your HVAC unit isn’t experiencing error codes.

“Cool On” or “Heat On” is Blinking

To start, verify your thermostat is switched to “cool” or “heat.”

Then, make sure it’s calling for the correct equipment to start. This is typically shown by “cool on,” “heat on” or a picture.

If this set of words or the illustration is blinking, your thermostat is in a five-minute delay state. This setting keeps your unit from damaging short cycling. This could occur if you lose power.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump needs service. Call TML Service Experts at 208-488-4892 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. Finish 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—Replace air filter. Clear the screen by touching “dismiss” after adding a new filter.
  • 184—Put in a new humidifier pad. Clear the monitor by hitting “dismiss” after adding a clean pad filter.
  • 185—Install a new dehumidifier filter. Clear the thermostat by hitting “dismiss” after putting in a clean filter.
  • 187—Rinse or install a new ventilator filter. Clear the thermostat by hitting “dismiss” after putting in a clean filter.
  • 188/189—Get a new UV bulb. Call TML Service Experts at 208-488-4892 for support.
  • 210—Register online for exterior temperature. Download the Lyric app to do this step and ensure correct thermostat operation.
  • 388—Register online for remote access and exterior temperature. Get the Lyric app to do 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 pick new Wi-Fi network.
  • 508—Wi-Fi not set up. Use the Lyric app and follow the procedure to link your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump must be serviced service. Contact TML Service Experts at 208-488-4892 for help.
  • 168—Wi-Fi radio error. Call TML Service Experts at 208-488-4892 for help.
  • 170—Internal memory error. Reach TML Service Experts at 208-488-4892 for assistance.
  • 171—Set date and time. Finish these settings so scheduling can operate.
  • 173—Thermostat temperature sensor error. Contact TML Service Experts at 208-488-4892 for support.
  • 175—AC power reconnected. No action required.
  • 177—Indoor temperature sensor error. Reach TML Service Experts at 208-488-4892 for help.
  • 178—Outdoor temperature sensor error. Call TML Service Experts at 208-488-4892 for help.
  • 181/182—Replace air filter. Clear the display by tapping “dismiss” after installing a clean filter.
  • 183—Clean humidifier tank and install a new water filter. Clear the thermostat by touching “dismiss” after doing these tasks.
  • 184—Install a new humidifier pad. Clear the thermostat by touching “dismiss” after installing pad filter.
  • 185—Install a new dehumidifier filter. Clear the screen by tapping “dismiss” after putting in a new filter.
  • 186—Clean ventilator core. Clear the monitor by hitting “dismiss” after doing this task.
  • 187—Rinse or get a new ventilator filter. Clear the display by tapping “dismiss” after getting a new filter.
  • 188/189—Get a new UV bulb. Reach TML Service Experts at 208-488-4892 for help.
  • 210—Register online for exterior temperature. Download the Lyric app to complete 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 proper thermostat operation.
  • 399—No Internet. Check 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, check this thermostat’s user manual.

Our Experts are Here to Help

If you’re still having problems after trying the troubleshooting list, our pros are ready to support you. Call us at 208-488-4892 and we’ll be out quickly to determine the problem.

If you rely on an older thermostat, right now is a good time to consider a new thermostat. Thermostat technology has come a long way in recent years Ask us for more details on how smart thermostats can make your residence comfier while helping save on heating and cooling expenses all year.

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