How to Troubleshoot Honeywell Thermostat Errors

Honeywell is one of the best thermostat manufacturers, and we proudly install them on a usual basis in Tempe. They’re durable and dependable. Also, Honeywell is regularly enhancing its technology, offering more features for your home.

However, every thermostat can have errors now and again. Due to this, we’ve prepared this helpful guidebook to walk you through troubleshooting. While Honeywell thermostat troubleshooting problems are rare, they do occur. 

While you can typically repair many thermostat issues alone, they occasionally need Expert support. Our home comfort pros are here to help when you need us. We’re merely a call away at 602-906-0111.

Let’s begin the process by finding out what model of thermostat your residence has.

What Type of Thermostat Do I Have?

There are three models of thermostats:

  • Manual—This is the typical dial-shaped thermostat. You won’t have error codes with this kind, but it’s also the least efficient for saving on heating and cooling bills.
  • Programmable—This thermostat features a digital screen and arrows you press to set your desired temperature. You can also choose daily programs to decrease the temperature when you’re gone and increase it when you return.
  • Smart—You won’t have to schedule any programs on this thermostat, since it adjusts to your routine. It automatically adjusts the temperature when you or family members are out and about to help you save on utility bills. You can also adjust the temperature anywhere via your phone or other Wi-Fi-enabled device. 

As you know many technologically advanced products, there are regular glitches that might occur. Many of these troubles don’t require Expert help and are uncomplicated enough to repair alone.

Common Honeywell Thermostat Troubleshooting Issues

All Honeywell thermostats have a special group of codes matching the issues that take place.

Think how uncomplicated it can be to repair a computer by restarting it. Many times, troubleshooting a thermostat can be just as easy.

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

Display is Blank

If the monitor is blank on your programmable thermostat, you could need to install new batteries. If that doesn’t take care of the issue or you have a smart thermostat, there may be a wiring issue.

Next, you should check the power is flowing for your furnace or air handler. Verify the switch close to the indoor system is switched “up”.

In addition to that, you should make certain all furnace cabinet or air handler doors/panels are tightly in place.

A panel that isn’t tight may trip the safety switch, which disconnects power to the unit.

Infrequently, an empty monitor could indicate you will need to get a new thermostat.

HVAC Equipment Won’t Turn On

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

When it’s hot, verify you set the thermostat lower than the ambient temperature. When it’s cold, verify it’s higher. This sounds silly, but we’ve seen it take place many times.

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

Equipment still won’t run? Confirm circuit breakers haven’t flipped and that your HVAC equipment isn’t showing error codes.

“Cool On” or “Heat On” is Blinking

To start, make sure your thermostat is set to “cool” or “heat.”

Then, check it’s signaling the correct unit to run. This is often demonstrated 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 mode keeps your unit from bad short cycling. This may happen if you lose power.

Honeywell Thermostat-Specific Error Codes

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

  • 164—Heat pump needs service. Call Orangutan Home Services at 602-906-0111 for help.
  • 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 occur.
  • 173—Thermostat temperature sensor error. Call Lyric technical support at 800-633-3991.
  • 175—AC power resumed. No action required.
  • 181/182—Install a new air filter. Clear the thermostat by touching “dismiss” after adding a new filter.
  • 184—Replace humidifier pad. Clear the monitor by hitting “dismiss” after putting in a clean pad filter.
  • 185—Install a new dehumidifier filter. Clear the display by touching “dismiss” after putting in a fresh filter.
  • 187—Wash or put in a new ventilator filter. Clear the screen by hitting “dismiss” after installing a new filter.
  • 188/189—Replace UV bulb. Call Orangutan Home Services at 602-906-0111 for support.
  • 210—Register online for outside temperature. Download the Lyric app to do this step and ensure correct thermostat operation.
  • 388—Register online for remote access and outdoor temperature. Get the Lyric app to do this step and ensure accurate thermostat operation.
  • 399—No Internet. Verify 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 link your thermostat.

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

Honeywell T6 Pro Smart Programmable Thermostat (TH411OU2005) 

  • 164—Heat pump must be serviced service. Contact Orangutan Home Services at 602-906-0111 for help.
  • 168—Wi-Fi radio error. Call Orangutan Home Services at 602-906-0111 for assistance.
  • 170—Internal memory error. Call Orangutan Home Services at 602-906-0111 for support.
  • 171—Set date and time. Finalize these settings so scheduling can work.
  • 173—Thermostat temperature sensor error. Call Orangutan Home Services at 602-906-0111 for help.
  • 175—AC power reconnected. No action necessary.
  • 177—Indoor temperature sensor error. Call Orangutan Home Services at 602-906-0111 for support.
  • 178—Outdoor temperature sensor error. Reach Orangutan Home Services at 602-906-0111 for support.
  • 181/182—Get a new air filter. Clear the thermostat by hitting “dismiss” after adding a fresh filter.
  • 183—Clean humidifier tank and replace water filter. Clear the screen by hitting “dismiss” after doing these steps.
  • 184—Install a new humidifier pad. Clear the display by hitting “dismiss” after adding a new pad filter.
  • 185—Install a new dehumidifier filter. Clear the display by tapping “dismiss” after adding a new filter.
  • 186—Rinse ventilator core. Clear the thermostat by tapping “dismiss” after finishing this task.
  • 187—Wash or replace ventilator filter. Clear the screen by tapping “dismiss” after getting a new filter.
  • 188/189—Add a new UV bulb. Reach Orangutan Home Services at 602-906-0111 for help.
  • 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. Get the Lyric app to do this step and ensure accurate thermostat operation.
  • 399—No Internet. Verify your network settings.
  • 400—No Wi-Fi signal. Wait for the thermostat to reconnect or select new Wi-Fi network.
  • 508—Wi-Fi not connected. Download the Lyric app and follow the procedures to connect your thermostat.

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

Our Experts are Available to Help

If you’re still running into troubles after going through the troubleshooting steps, our pros are ready to support you. Call us at 602-906-0111 and we’ll be out quickly to determine the problem.

If you use an aging thermostat, today is a great time to think about a new device. Thermostat technology has gotten better over the last few years. Ask us for more info on how smart thermostats can make your residence more comfortable while helping save on energy expenses all year.


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