Expanded exact-code directory
Honeywell Home T6 Pro Smart thermostat error codes
Honeywell Home T6 Pro Smart thermostat indicators as Resideo lists them, each with its meaning and the first safe check.
- 164-heat-pump-needs-serviceHeat Pump Needs Service.
- 168-wifi-radio-errorWiFi Radio Error. The wireless module is not
- 170-internal-memory-errorInternal Memory Error. The thermostat's memory has encountered
- 173-thermostat-temperature-sensor-errorThermostat Temperature Sensor Error. The temperature sensor on
Honeywell Home T6 Pro Smart thermostat alert 171: meaning and exact next steps
alert 171 means Set the Date and Time. The time and date on the thermostat need to be set so features like scheduling can operate.
Open record Honeywell Home T6 Pro Smart thermostat · exact signalHoneywell Home T6 Pro Smart thermostat alert 183, 184, 185, 186, 187, 188 or 189: meaning and exact next steps
alert 183, 184, 185, 186, 187, 188 or 189 means Accessory maintenance reminders: 183 Clean Humidifier Tank and Replace Water Filter; 184 Replace Humidifier Pad; 185 Replace Dehumidifier Filter; 186 Clean Ventilator Core; 187 Clean or Replace Ventilator Filter; 188 and 189 Replace UV Bulb.
Open record Honeywell Home T6 Pro Smart thermostat · exact signalHoneywell Home T6 Pro Smart thermostat blank screen or unresponsive system: meaning and exact next steps
blank screen or unresponsive system means The thermostat has no display power, or it is not getting a response from the system.
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Every Honeywell Home T6 Pro Smart thermostat code: what it means and what to do
- 164-heat-pump-needs-service
- 168-wifi-radio-error
- 170-internal-memory-error
- 173-thermostat-temperature-sensor-error
- 175-ac-power-resumed
- 177-178-wired-temperature-sensor-error
- 181-182-replace-air-filter
- 210-388-register-online
- 399-no-internet
- 400-no-wifi-signal
- 508-wifi-not-configured
- cool-on-or-heat-on-flashing-compressor-protection
Honeywell Home T6 Pro Smart thermostat code 164-heat-pump-needs-service
Heat Pump Needs Service.
Note the code and whether the heat pump is running.
The T6 Pro guide's recommended action is to contact your heating or cooling professional to diagnose and service the heat pump.
Honeywell Home T6 Pro Smart thermostat code 168-wifi-radio-error
WiFi Radio Error. The wireless module is not operating, and wireless features are not available.
Note that the thermostat itself can still be adjusted at the screen.
The T6 Pro guide says to contact your heating or cooling professional for assistance. It also says the thermostat still works if the Wi-Fi connection is lost, and that features managed through the Resideo app, such as geofencing, will not function without it.
Honeywell Home T6 Pro Smart thermostat code 170-internal-memory-error
Internal Memory Error. The thermostat's memory has encountered an error.
Note the code and the model number.
The T6 Pro guide says to contact your heating or cooling professional for assistance.
Honeywell Home T6 Pro Smart thermostat code 173-thermostat-temperature-sensor-error
Thermostat Temperature Sensor Error. The temperature sensor on the thermostat has encountered an error.
Compare the thermostat's reading with a separate thermometer in the same room.
The T6 Pro guide says to contact your heating or cooling professional for assistance.
Honeywell Home T6 Pro Smart thermostat code 175-ac-power-resumed
AC Power Resumed. AC power to the thermostat has been restored after a power loss.
Nothing is wrong: check that the heating or cooling system is running again.
The T6 Pro guide says you do not need to take any action.
Honeywell Home T6 Pro Smart thermostat code 177-178-wired-temperature-sensor-error
Indoor Temperature Sensor Error (177) or Outdoor Temperature Sensor Error (178). The wired sensor is not connected, or there is a wiring short.
Look at whether a wired indoor or outdoor sensor is fitted to the thermostat.
The T6 Pro guide says to contact your heating or cooling professional for assistance.
Honeywell Home T6 Pro Smart thermostat code 181-182-replace-air-filter
Replace Air Filter. These are maintenance reminders, not faults.
Look at the system's air filter.
The T6 Pro guide's action: replace the air filter or contact your heating or cooling professional, then reset the timer by touching Dismiss on the thermostat screen after replacement.
Honeywell Home T6 Pro Smart thermostat code 210-388-register-online
Register Online. 210 says you need to register online to receive outdoor temperature information from the internet. 388 says you need to register online for remote thermostat access and outdoor temperature information.
Check whether the thermostat has been added to a Resideo account.
The T6 Pro guide says to download the Resideo app and register your thermostat. The guide says that, based on the installation settings, the outdoor temperature information is required for correct operation of your system for 210.
Honeywell Home T6 Pro Smart thermostat code 399-no-internet
No Internet. The internet connection has been lost.
Check whether other devices can reach the internet.
The T6 Pro guide's action is to check your network settings. It adds that the thermostat still works manually while offline and reconnects automatically once the network is restored.
Honeywell Home T6 Pro Smart thermostat code 400-no-wifi-signal
No WiFi Signal. The WiFi signal has been lost.
Wait a few minutes for the thermostat to reconnect.
The T6 Pro guide's steps: wait for the thermostat to reconnect or select a new WiFi network in the app. Its FAQ says to wait 5 minutes for the reconnect or pick an alternate network, and if it cannot reconnect, troubleshoot the router. It notes the thermostat uses the 2.4 GHz band, so a phone may see a network the thermostat cannot.
Honeywell Home T6 Pro Smart thermostat code 508-wifi-not-configured
WiFi Not Configured.
Open the Resideo app and check whether the thermostat is added.
The T6 Pro guide's action is to download the Resideo app and follow the steps to connect the thermostat to WiFi.
Honeywell Home T6 Pro Smart thermostat code cool-on-or-heat-on-flashing-compressor-protection
The compressor protection feature is engaged. The T6 Pro guide says to wait a few minutes for the system to restart safely to avoid damaging the compressor.
Wait a few minutes without changing the setpoint.
The T6 Pro guide says the message is not a fault: wait a few minutes for the system to restart. It warns that compressor protection is bypassed during testing, so avoid cycling the compressor quickly.
Resideo — T6 Pro Smart Thermostat user guide 33-00410EFS: Alerts and maintenance reminders