How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the leading thermostat brands, and we proudly install them on a frequent basis in Concord. They’re durable and trustworthy. Also, Honeywell is regularly advancing its technology, bringing more features for your residence.

However, every thermostat can experience issues every so often. As a result, we’ve put together this valuable guidebook to walk you through troubleshooting.

While you can often fix many thermostat troubles alone, they often call for Expert assistance. Our home comfort Experts are here to support you when you need us. We’re only a call away at 925-384-1303.

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

What Type of Thermostat Do I Have?

There are three kinds of thermostats:

  • Manual—This is the typical dial-shaped thermostat. You won’t run into error codes with this kind, but it’s also the least efficient for saving on heating and cooling expenses.
  • Programmable—This thermostat includes a digital screen and arrows you press to choose your desired temperature. You can also choose daily programs to reduce the temperature when you’re gone and raise it when you return.
  • Smart—You won’t have to set any programs on this thermostat, since it learns your day. It automatically adjusts the temperature when you or family members are gone to help you save on energy bills. You can also adjust the temperature anywhere using your phone or other Wi-Fi-enabled device. 

As is the case with many technologically advanced solutions, there are regular malfunctions that can happen. Many of these problems don’t call for pro support and are simple to repair on your own.

Common Honeywell Thermostat Troubles

All thermostats have an exclusive set of codes matching the malfunctions that happen.

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

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

Display is Blank

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

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

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

An unsecured panel may trip the safety switch, which cuts off power to the equipment.

Less frequently, a blank screen might mean you will need to replace your thermostat.

Heating and Cooling Unit Won’t Work

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

When it’s hot, make sure you schedule the thermostat lower than the current temperature. When it’s cool, verify it’s higher. This sounds absurd, but we’ve seen it occur many times.

Confirm the power switch close to your indoor system is in the “on” position. You should also comfirm the cabinet doors or panels are closed on your furnace cabinet or air handler. An open panel can trigger the safety switch, stopping current to the equipment.

System still won’t start? Make sure circuit breakers haven’t tripped and that your HVAC equipment isn’t displaying error codes.

“Cool On” or “Heat On” is Flashing

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

Then, check it’s calling for the correct equipment to run. This is typically demonstrated by “cool on,” “heat on” or an illustration.

If these words or the illustration is pulsing, your thermostat is in a five-minute delay state. This setting keeps your system 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 Freschi Service Experts at 925-384-1303 for help.
  • 168—Wi-Fi radio error. Contact Lyric technical support at 800-633-3991. 170—Internal memory error. Contact 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—Put in a new air filter. Clear the thermostat by hitting “dismiss” after putting in a new filter.
  • 184—Install a new humidifier pad. Clear the monitor by touching “dismiss” after installing a new pad filter.
  • 185—Put in a new dehumidifier filter. Clear the monitor by hitting “dismiss” after putting in a new filter.
  • 187—Clean or put in a new ventilator filter. Clear the display by tapping “dismiss” after installing a fresh filter.
  • 188/189—Get a new UV bulb. Ring Freschi Service Experts at 925-384-1303 for assistance.
  • 210—Register online for exterior temperature. Download the Lyric app to finish this step and ensure correct thermostat operation.
  • 388—Register online for remote access and outdoor 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 set up. Use the Lyric app and follow the steps to configure your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump requires service. Call Freschi Service Experts at 925-384-1303 for assistance.
  • 168—Wi-Fi radio error. Reach Freschi Service Experts at 925-384-1303 for assistance.
  • 170—Internal memory error. Reach Freschi Service Experts at 925-384-1303 for assistance.
  • 171—Set date and time. Complete these settings so scheduling can run.
  • 173—Thermostat temperature sensor error. Call Freschi Service Experts at 925-384-1303 for help.
  • 175—AC power restored. No action required.
  • 177—Indoor temperature sensor error. Contact Freschi Service Experts at 925-384-1303 for support.
  • 178—Outdoor temperature sensor error. Contact Freschi Service Experts at 925-384-1303 for support.
  • 181/182—Get a new air filter. Clear the screen by tapping “dismiss” after installing a new filter.
  • 183—Wash humidifier tank and replace water filter. Clear the screen by hitting “dismiss” after finishing these steps.
  • 184—Install a new humidifier pad. Clear the thermostat by hitting “dismiss” after getting a new pad filter.
  • 185—Install a new dehumidifier filter. Clear the display by tapping “dismiss” after installing a new filter.
  • 186—Rinse ventilator core. Clear the monitor by hitting “dismiss” after doing this task.
  • 187—Clean or get a new ventilator filter. Clear the display by hitting “dismiss” after getting a new filter.
  • 188/189—Add a new UV bulb. Get in touch with Freschi Service Experts at 925-384-1303 for assistance.
  • 210—Register online for exterior temperature. Download the Lyric app to finish this step and ensure correct thermostat operation.
  • 388—Register online for remote access and exterior temperature. Get the Lyric app to finish 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 pick new Wi-Fi network.
  • 508—Wi-Fi not set up. Download the Lyric app and follow the process to connect your thermostat.

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

Our Experts are Available to Help

If you’re still experiencing issues after working through the troubleshooting process, our Experts are here to assist you. Reach us at 925-384-1303 and we’ll come to your house as fast as we can to figure out the malfunction.

If you have an aging thermostat, now is a good time to consider a new device. Thermostat technology has advanced lately Ask us for more info on how smart thermostats can make your home more comfortable while helping save on heating and cooling expenses all year.

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