How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the best thermostat brands, and we proudly install them on a regular basis in Edmonton. They’re sturdy and trustworthy. Plus, Honeywell is regularly improving its technology, offering more features for your house.

Still, all thermostats can run into problems from time to time. Due to this, we’ve put together this useful guidebook to walk you through troubleshooting. While Honeywell thermostat troubleshooting problems are rare, they do pop up. 

While you can usually repair many thermostat troubles by yourself, they often call for Expert support. Our home comfort pros are ready to assist you when you need us. We’re only a call away at 587-404-0790.

Let’s start the process by determining what type of thermostat your home 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 experience error codes with this type, but it’s also the least efficient for reducing utility costs.
  • Programmable—This thermostat features a digital screen and arrows you press to choose your desired temperature. You can also use daily programs to decrease the temperature when you’re gone and raise it when you get back.
  • Smart—You won’t have to make any programs on this thermostat, because it learns your day. It automatically changes the temperature when you or other household members are out and about to help you save on utility expenses. You can also adjust the temperature anywhere on your phone or other Wi-Fi-enabled device. 

As you know the majority of technologically advanced products, there are common malfunctions that can take place. The majority of of these problems don’t require pro support and are uncomplicated enough to fix by yourself.

Common Honeywell Thermostat Troubleshooting Issues

All Honeywell thermostats have an exclusive group of codes assigned to the troubles that take place.

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

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

Display is Blank

If the screen is blank on your programmable thermostat, you may need to replace the batteries. If that doesn’t fix the trouble or you use a smart thermostat, there may be a wiring malfunction.

Next, you should make sure the power is on for your furnace or air handler. Confirm the switch by the indoor unit is in the “on” position.

Also, you should make certain all furnace cabinet or air handler doors/panels are tightly fastened.

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

Less frequently, a blank monitor might mean you should get a new thermostat.

Heating and Cooling System Won’t Turn On

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

When it’s hot, verify you schedule the thermostat beneath the room temperature. When it’s cold, make sure it’s higher. This sounds silly, but we’ve seen it take place lots of times.

Ensure the power switch by 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. A loose panel can trip the safety switch, diverting electricity to the unit.

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

“Cool On” or “Heat On” is Blinking

To begin, check your thermostat is switched to “cool” or “heat.”

Then, ensure it’s signaling the correct unit to start. This is often indicated by “cool on,” “heat on” or an icon.

If this set of words or the illustration is flashing, your thermostat is in a five-minute delay status. This setting protects your equipment from bad short cycling. This can take place if you lose electricity.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump needs service. Call Service Experts Heating & Air Conditioning at 587-404-0790 for support.
  • 168—Wi-Fi radio error. Reach 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. Call Lyric technical support at 800-633-3991.
  • 175—AC power resumed. No action necessary.
  • 181/182—Put in a new air filter. Clear the screen by tapping “dismiss” after adding a clean filter.
  • 184—Put in a new humidifier pad. Clear the screen by hitting “dismiss” after putting in a clean pad filter.
  • 185—Replace dehumidifier filter. Clear the display by hitting “dismiss” after adding a fresh filter.
  • 187—Wash or replace ventilator filter. Clear the monitor by tapping “dismiss” after adding a clean filter.
  • 188/189—Replace UV bulb. Contact Service Experts Heating & Air Conditioning at 587-404-0790 for assistance.
  • 210—Register online for exterior temperature. Use the Lyric app to finish this step and ensure proper thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Download the Lyric app to do this step and ensure accurate thermostat operation.
  • 399—No Internet. Check your network settings.
  • 400—No Wi-Fi signal. Wait for the thermostat to reconnect or pick new Wi-Fi network.
  • 508—Wi-Fi not configured. Get the Lyric app and follow the process to configure your thermostat.

For more details, look at this thermostat’s user manual.

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump requires service. Call Service Experts Heating & Air Conditioning at 587-404-0790 for help.
  • 168—Wi-Fi radio error. Reach Service Experts Heating & Air Conditioning at 587-404-0790 for support.
  • 170—Internal memory error. Contact Service Experts Heating & Air Conditioning at 587-404-0790 for assistance.
  • 171—Set date and time. Complete these settings so scheduling can work.
  • 173—Thermostat temperature sensor error. Call Service Experts Heating & Air Conditioning at 587-404-0790 for help.
  • 175—AC power restored. No action required.
  • 177—Indoor temperature sensor error. Call Service Experts Heating & Air Conditioning at 587-404-0790 for help.
  • 178—Outdoor temperature sensor error. Reach Service Experts Heating & Air Conditioning at 587-404-0790 for help.
  • 181/182—Replace air filter. Clear the monitor by hitting “dismiss” after adding a clean filter.
  • 183—Clean humidifier tank and add a new water filter. Clear the monitor by tapping “dismiss” after finishing these tasks.
  • 184—Replace humidifier pad. Clear the monitor by hitting “dismiss” after installing pad filter.
  • 185—Replace dehumidifier filter. Clear the monitor by tapping “dismiss” after installing a clean filter.
  • 186—Clean ventilator core. Clear the monitor by hitting “dismiss” after completing this task.
  • 187—Wash or get a new ventilator filter. Clear the monitor by touching “dismiss” after installing a new filter.
  • 188/189—Replace UV bulb. Contact Service Experts Heating & Air Conditioning at 587-404-0790 for help.
  • 210—Register online for outdoor temperature. Get the Lyric app to finish this step and ensure correct thermostat operation.
  • 388—Register online for remote access and exterior temperature. Download the Lyric app to complete 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 pick new Wi-Fi network.
  • 508—Wi-Fi not configured. Get the Lyric app and follow the procedures to connect your thermostat.

For more details, look at this thermostat’s user manual.

Our Experts are Here to Provide Assistance

If you’re still running into problems after working through the troubleshooting process, our Experts are ready to help. Give us a call at 587-404-0790 and we’ll arrive rapidly to figure out the malfunction.

If you have an aging thermostat, today is a good time to think about a replacement. Thermostat technology has come a long way over the last few years. Ask us for more details on how smart thermostats can make your home more comfortable while helping save on heating and cooling bills all year.

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