How to Troubleshoot Honeywell Thermostat Errors

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

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

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

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

What Type of Thermostat Do I Have?

There are three models of thermostats:

  • Manual—This is the older dial-shaped thermostat. You won’t run into 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 press to choose your desired temperature. You can also use daily programs to reduce the temperature when you’re away and raise it when you get back.
  • Smart—You won’t have to set any programs on this thermostat, as it learns your routine. It instinctively adjusts the temperature when you or loved ones are out and about 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 glitches that can take place. Many of these problems don’t need Expert help and are simple to repair on your own.

Common Honeywell Thermostat Troubles

All thermostats have an exclusive set of codes that correspond to the glitches that happen.

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

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

Display is Blank

If the monitor is empty 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 flowing for your furnace or air handler. Make sure the switch by the indoor equipment is switched “up”.

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 system.

While it’s less common, a blank screen might mean you should replace your thermostat.

Heating and Cooling Equipment Won’t Work

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

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

Confirm the power switch by your indoor equipment is in the “on” position. You should also comfirm the cabinet doors or panels are tight on your furnace cabinet or air handler. An open panel can activate the safety switch, diverting electricity to the equipment.

System still won’t run? 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 unit to run. This is often shown by “cool on,” “heat on” or a picture.

If these words or the illustration is pulsing, your thermostat is in a five-minute delay state. This feature keeps your system from harmful 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 support.
  • 168—Wi-Fi radio error. Contact Lyric technical support at 800-633-3991. 170—Internal memory error. Reach Lyric technical support at 800-633-3991.
  • 171—Set date and time. Finalize these settings so scheduling can take place.
  • 173—Thermostat temperature sensor error. Call Lyric technical support at 800-633-3991.
  • 175—AC power restored. No action needed.
  • 181/182—Install a new air filter. Clear the monitor by tapping “dismiss” after adding a new filter.
  • 184—Install a new humidifier pad. Clear the monitor by touching “dismiss” after installing a new pad filter.
  • 185—Install a new dehumidifier filter. Clear the screen by hitting “dismiss” after adding a new filter.
  • 187—Clean or install 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 accurate thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Use the Lyric app to do 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 choose new Wi-Fi network.
  • 508—Wi-Fi not set. Get the Lyric app and follow the steps to configure your thermostat.

For more specifics, look at 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. Contact 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 support.
  • 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—Install a new air filter. Clear the monitor by tapping “dismiss” after installing a new filter.
  • 183—Wash humidifier tank and replace water filter. Clear the monitor by hitting “dismiss” after doing these steps.
  • 184—Get a new humidifier pad. Clear the thermostat by tapping “dismiss” after adding a new pad filter.
  • 185—Get a new dehumidifier filter. Clear the display by tapping “dismiss” after installing a new filter.
  • 186—Wash ventilator core. Clear the monitor by tapping “dismiss” after doing this task.
  • 187—Clean or get a new ventilator filter. Clear the monitor by tapping “dismiss” after buying a new filter.
  • 188/189—Add a new UV bulb. Reach 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 accurate thermostat operation.
  • 388—Register online for remote access and exterior temperature. Use 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 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 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. Call us at 925-384-1303 and we’ll come to your house as fast as we can to determine the issue.

If you have a dated thermostat, now is a good time to consider a new thermostat. Thermostat technology has gotten better in recent years Ask us for more details on how smart thermostats can make your home more comfortable while helping save on heating and cooling expenses all year.

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