How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the leading thermostat brands, and we proudly install them on a regular basis in Denver. They’re long-lasting and reliable. In addition, Honeywell is regularly updating its technology, offering more features for your household.

Nevertheless, all thermostats can have errors now and again. As a result, we’ve put together this useful guide to go over troubleshooting. While Honeywell thermostat problems are rare, they do occur. 

While you can often solve many thermostat problems on your own, they often require Expert help. Our heating and cooling pros are available to help when you need us. We’re only a call away at 303-647-5853.

Let’s start the process by determining what kind of thermostat your home has.

What Model of Thermostat Do I Have?

There are three models of thermostats:

  • Manual—This is the older dial-shaped thermostat. You won’t experience error codes with this type, but it’s also the least efficient for saving on heating and cooling bills.
  • Programmable—This thermostat includes a digital screen and arrows you use to choose your desired temperature. You can also choose daily programs to reduce the temperature when you’re gone and increase it when you come home.
  • Smart—You won’t have to make any programs on this thermostat, as it learns your schedule. It instinctively adjusts the temperature when you or other household members are away to help you save on utility bills. You can also raise or lower the temperature anywhere via your phone or other Wi-Fi-enabled device. 

As is the case with many technologically advanced products, there are common glitches that might take place. Many of these problems don’t call for pro support and are simple to repair alone.

Common Honeywell Thermostat Troubles

Every thermostat has a special kind of codes that correspond to the glitches 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 easy.

Here are some of the most reported Honeywell thermostat issues. These are applicable to the following programmable thermostats:

Display is Blank

If the monitor is empty on your programmable thermostat, you might need to replace the batteries. If that doesn’t fix the trouble or you rely on a smart thermostat, there might be a wiring malfunction.

Next, you should make sure the power is enabled for your furnace or air handler. Verify the switch near the indoor system is switched “on”.

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

An unsecured panel may activate the safety switch, which stops power to the system.

While it’s less common, an empty screen may indicate you will need to replace your thermostat.

Heating and Cooling System Won’t Run

Check that your thermostat is switched to “cool” or “heat,” not “off.”

In the summer, verify you set the thermostat below the current temperature. In the winter, confirm it’s higher. This sounds silly, but we’ve seen it take place a lot of times.

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

System still won’t run? Make sure circuit breakers haven’t turned off and that your HVAC system isn’t experiencing error codes.

“Cool On” or “Heat On” is Blinking

First, ensure your thermostat is on “cool” or “heat.”

Then, verify it’s calling for the correct system to start. This is typically indicated by “cool on,” “heat on” or an illustration.

If this phrase or the icon is pulsing, your thermostat is in a five-minute delay state. This setting stops your system from damaging short cycling. This may happen if your power is interrupted.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump needs service. Call Service Experts Heating & Air Conditioning at 303-647-5853 for help.
  • 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. Complete these settings so scheduling can run.
  • 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 screen by tapping “dismiss” after putting in a fresh filter.
  • 184—Replace humidifier pad. Clear the display by touching “dismiss” after adding a clean pad filter.
  • 185—Install a new dehumidifier filter. Clear the screen by tapping “dismiss” after adding a new filter.
  • 187—Clean or replace ventilator filter. Clear the screen by tapping “dismiss” after adding a clean filter.
  • 188/189—Replace UV bulb. Call Service Experts Heating & Air Conditioning at 303-647-5853 for assistance.
  • 210—Register online for exterior 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 finish this step and ensure correct 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. Get the Lyric app and follow the procedure to connect your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump needs service. Contact Service Experts Heating & Air Conditioning at 303-647-5853 for support.
  • 168—Wi-Fi radio error. Reach Service Experts Heating & Air Conditioning at 303-647-5853 for support.
  • 170—Internal memory error. Contact Service Experts Heating & Air Conditioning at 303-647-5853 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 303-647-5853 for assistance.
  • 175—AC power restored. No action required.
  • 177—Indoor temperature sensor error. Contact Service Experts Heating & Air Conditioning at 303-647-5853 for assistance.
  • 178—Outdoor temperature sensor error. Reach Service Experts Heating & Air Conditioning at 303-647-5853 for support.
  • 181/182—Install a new air filter. Clear the monitor by hitting “dismiss” after putting in a fresh filter.
  • 183—Rinse humidifier tank and replace water filter. Clear the screen by touching “dismiss” after completing these procedures.
  • 184—Install a new humidifier pad. Clear the screen by touching “dismiss” after getting a new pad filter.
  • 185—Get a new dehumidifier filter. Clear the display by touching “dismiss” after putting in a new filter.
  • 186—Wash ventilator core. Clear the screen by touching “dismiss” after finishing this task.
  • 187—Rinse or replace ventilator filter. Clear the monitor by tapping “dismiss” after installing a new filter.
  • 188/189—Replace UV bulb. Get in touch with Service Experts Heating & Air Conditioning at 303-647-5853 for help.
  • 210—Register online for exterior temperature. Use 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 accurate 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. Use the Lyric app and follow the steps to connect your thermostat.

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

Our Experts are Ready to Help

If you’re still experiencing troubles after working through the troubleshooting list, our professionals are ready to support you. Give us a call at 303-647-5853 and we’ll be out rapidly to figure out the problem.

If you use an aging thermostat, right now is a great time to consider a replacement. 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 energy bills throughout the year.

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