How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the leading thermostat producers, and we proudly install them on a frequent basis in Gainesville. They’re durable and trustworthy. In addition, Honeywell is regularly updating its technology, resulting in more features for your house.

Still, every thermostat can have errors every now and then. That’s why we’ve compiled this helpful manual to run through troubleshooting. While Honeywell thermostat problems are rare, they do pop up. 

While you can often solve most thermostat problems on your own, they occasionally require Expert support. Our HVAC Experts are ready to help when you need us. We’re merely a call away at 352-414-4006.

Let’s get started with the process by determining what model 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 run into error codes with this kind, but it’s also the least efficient for lowering utility bills.
  • Programmable—This thermostat features a digital screen and arrows you touch to determine your desired temperature. You can also choose daily programs to decrease the temperature when you’re at work and raise it when you get back.
  • Smart—You won’t have to make any programs on this thermostat, because it adjusts to your schedule. It instinctively adjusts the temperature when you or family members are away to help you save on utility expenses. You can also adjust the temperature anywhere on your phone or other Wi-Fi-enabled device. 

As is the case with the majority of technologically advanced things, there are common problems that can take place. Many of these problems don’t require Expert assistance and are simple to solve alone.

Common Honeywell Thermostat Issues

Each thermostat has a special group of codes assigned to the issues that happen.

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

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

Display is Blank

If the monitor is clear on your programmable thermostat, you may need to replace the batteries. If that doesn’t take care of the malfunction or you have a smart thermostat, there might be a wiring issue.

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

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

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

Infrequently, a clear screen might indicate you need to install a new thermostat.

Heating and Cooling System Won’t Start

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

During warm weather, make sure you set the thermostat lower than the current temperature. When it’s cool, make sure it’s higher. This sounds goofy, but we’ve seen it take place lots of times.

Ensure the power switch by your indoor system is in the “on” position. You should also make sure the cabinet doors or panels are tight on your furnace cabinet or air handler. An unsecured panel can trigger the safety switch, diverting power to the equipment.

Heating or cooling still won’t turn on? Confirm circuit breakers haven’t tripped and that your HVAC unit isn’t experiencing error codes.

“Cool On” or “Heat On” is Blinking

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

Then, ensure it’s telling the right unit to turn on. This is often demonstrated by “cool on,” “heat on” or an illustration.

If this set of words or the picture is blinking, your thermostat is in a five-minute delay mode. This setting keeps your equipment from bad short cycling. This can occur if you lose power.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump needs service. Call Service Experts Heating & Air Conditioning at 352-414-4006 for support.
  • 168—Wi-Fi radio error. Reach 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 take place.
  • 173—Thermostat temperature sensor error. Contact Lyric technical support at 800-633-3991.
  • 175—AC power restarted. No action required.
  • 181/182—Put in a new air filter. Clear the monitor by tapping “dismiss” after putting in a new filter.
  • 184—Install a new humidifier pad. Clear the display by tapping “dismiss” after installing a new pad filter.
  • 185—Install a new dehumidifier filter. Clear the display by hitting “dismiss” after installing a fresh filter.
  • 187—Wash or install a new ventilator filter. Clear the screen by tapping “dismiss” after installing a new filter.
  • 188/189—Replace UV bulb. Contact Service Experts Heating & Air Conditioning at 352-414-4006 for support.
  • 210—Register online for outside temperature. Use the Lyric app to do this step and ensure correct thermostat operation.
  • 388—Register online for remote access and outside temperature. Use the Lyric app to do 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. Get the Lyric app and follow the process to connect your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump needs service. Reach Service Experts Heating & Air Conditioning at 352-414-4006 for support.
  • 168—Wi-Fi radio error. Reach Service Experts Heating & Air Conditioning at 352-414-4006 for help.
  • 170—Internal memory error. Reach Service Experts Heating & Air Conditioning at 352-414-4006 for support.
  • 171—Set date and time. Finalize these settings so scheduling can work.
  • 173—Thermostat temperature sensor error. Contact Service Experts Heating & Air Conditioning at 352-414-4006 for support.
  • 175—AC power resumed. No action needed.
  • 177—Indoor temperature sensor error. Reach Service Experts Heating & Air Conditioning at 352-414-4006 for help.
  • 178—Outdoor temperature sensor error. Reach Service Experts Heating & Air Conditioning at 352-414-4006 for help.
  • 181/182—Get a new air filter. Clear the display by tapping “dismiss” after installing a fresh filter.
  • 183—Wash humidifier tank and replace water filter. Clear the display by touching “dismiss” after completing these steps.
  • 184—Get a new humidifier pad. Clear the display by tapping “dismiss” after getting a new pad filter.
  • 185—Install a new dehumidifier filter. Clear the monitor by tapping “dismiss” after adding a clean filter.
  • 186—Wash ventilator core. Clear the monitor by hitting “dismiss” after finishing this task.
  • 187—Clean or get a new ventilator filter. Clear the screen by tapping “dismiss” after installing a new filter.
  • 188/189—Add a new UV bulb. Get in touch with Service Experts Heating & Air Conditioning at 352-414-4006 for support.
  • 210—Register online for outside temperature. Use the Lyric app to complete this step and ensure accurate thermostat operation.
  • 388—Register online for remote access and exterior temperature. Get 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 pick new Wi-Fi network.
  • 508—Wi-Fi not set up. Use the Lyric app and follow the steps to connect your thermostat.

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

Our Experts are Available to Provide Assistance

If you’re still having problems after going through the troubleshooting list, our professionals are here to help. Give us a call at 352-414-4006 and we’ll come to your house rapidly to figure out the issue.

If you rely on an older thermostat, right now is a good time to consider a replacement. Thermostat technology has advanced over the last few years. Ask us for more information on how smart thermostats can make your home more comfortable while helping save on heating and cooling bills year-round.

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