How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the leading thermostat producers, and we proudly install them on a frequent basis in Tulsa. They’re long-lasting and reliable. Also, Honeywell is frequently enhancing its technology, offering more features for your family.

However, each thermostat can experience issues from time to time. As a result, we’ve put together this valuable handbook to run through troubleshooting.

While you can usually repair most thermostat issues on your own, they sometimes call for Expert help. Our HVAC pros are here to help when you need us. We’re just a call away at 918-212-8927.

Let’s start the process by determining what model 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 run into error codes with this one, but it’s also the least efficient for reducing energy costs.
  • Programmable—This thermostat features a digital screen and arrows you use to determine your desired temperature. You can also choose daily programs to reduce the temperature when you’re away and set it higher when you get back.
  • Smart—You won’t have to schedule any programs on this thermostat, because it learns your schedule. It intuitively raises and lowers the temperature when you or other household members are away to help you save on utility expenses. You can also raise or lower the temperature anywhere on your phone or other Wi-Fi-enabled device. 

As is the case with many technologically advanced solutions, there are common glitches that may occur. The majority of of these problems don’t call for professional help and are uncomplicated enough to repair by yourself.

Common Honeywell Thermostat Problems

Each thermostat has an exclusive group of codes that correspond to the troubles that take place.

Think how easy it can be to restore a computer by restarting it. In many instances, troubleshooting a thermostat can be just as easy.

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

Display is Blank

If the screen is clear on your programmable thermostat, you may need to replace the batteries. If that doesn’t fix the issue or you rely on a smart thermostat, there may be a wiring issue.

Next, you should make sure the power is on for your furnace or air handler. Confirm the switch near the indoor unit is switched “up”.

Also, you should confirm all furnace cabinet or air handler doors/panels are tightly secured.

A loose panel may trip the safety switch, which disconnects power to the unit.

While it’s less common, a blank display may indicate you will need to install a new thermostat.

HVAC System Won’t Turn On

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

When it’s hot, verify you schedule the thermostat below the current temperature. When it’s cool, confirm it’s higher. This sounds goofy, but we’ve seen it occur many times.

Make sure the power switch near your indoor system is in the “on” position. You should also check the cabinet doors or panels are closed on your furnace cabinet or air handler. An unsecured panel can trigger the safety switch, stopping power to the unit.

System still won’t start? Confirm circuit breakers haven’t turned off 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, verify it’s telling the right equipment to start. This is usually indicated by “cool on,” “heat on” or a picture.

If these words or the icon is blinking, your thermostat is in a five-minute delay mode. This mode keeps your equipment from bad short cycling. This could occur if you lose power.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump requires service. Call Jack Nelson Service Experts at 918-212-8927 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. Complete these settings so scheduling can run.
  • 173—Thermostat temperature sensor error. Reach Lyric technical support at 800-633-3991.
  • 175—AC power restarted. No action needed.
  • 181/182—Install a new air filter. Clear the thermostat by touching “dismiss” after adding a fresh filter.
  • 184—Install a new humidifier pad. Clear the display by hitting “dismiss” after adding a clean pad filter.
  • 185—Put in a new dehumidifier filter. Clear the monitor by tapping “dismiss” after adding a clean filter.
  • 187—Wash or install a new ventilator filter. Clear the thermostat by touching “dismiss” after adding a clean filter.
  • 188/189—Install a new UV bulb. Contact Jack Nelson Service Experts at 918-212-8927 for support.
  • 210—Register online for outside temperature. Use the Lyric app to finish this step and ensure proper thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Use the Lyric app to complete 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 set. Get the Lyric app and follow the steps to configure your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump must be serviced service. Reach Jack Nelson Service Experts at 918-212-8927 for assistance.
  • 168—Wi-Fi radio error. Contact Jack Nelson Service Experts at 918-212-8927 for support.
  • 170—Internal memory error. Call Jack Nelson Service Experts at 918-212-8927 for support.
  • 171—Set date and time. Finish these settings so scheduling can work.
  • 173—Thermostat temperature sensor error. Reach Jack Nelson Service Experts at 918-212-8927 for assistance.
  • 175—AC power resumed. No action required.
  • 177—Indoor temperature sensor error. Reach Jack Nelson Service Experts at 918-212-8927 for assistance.
  • 178—Outdoor temperature sensor error. Call Jack Nelson Service Experts at 918-212-8927 for support.
  • 181/182—Install a new air filter. Clear the monitor by touching “dismiss” after adding a fresh filter.
  • 183—Wash humidifier tank and add a new water filter. Clear the display by hitting “dismiss” after doing these steps.
  • 184—Install a new humidifier pad. Clear the screen by hitting “dismiss” after getting a new pad filter.
  • 185—Get a new dehumidifier filter. Clear the monitor by tapping “dismiss” after adding a clean filter.
  • 186—Clean ventilator core. Clear the monitor by touching “dismiss” after doing this task.
  • 187—Wash or install a new ventilator filter. Clear the screen by tapping “dismiss” after installing a new filter.
  • 188/189—Install a new UV bulb. Reach Jack Nelson Service Experts at 918-212-8927 for assistance.
  • 210—Register online for outdoor temperature. Get the Lyric app to do this step and ensure proper thermostat operation.
  • 388—Register online for remote access and outside temperature. Download the Lyric app to finish this step and ensure proper 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 process to connect your thermostat.

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

Our Experts are Here to Provide Assistance

If you’re still running into problems after trying the troubleshooting process, our Experts are here to help. Call us at 918-212-8927 and we’ll come to your house rapidly to diagnose the malfunction.

If you have an older thermostat, now is a fantastic time to think about a replacement. Thermostat technology has gotten better in recent years Ask us for more info on how smart thermostats can make your house better while helping save on energy expenses throughout the year.

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