Thermostats Error Codes

Incorrect keypad lockout password entered — the display flashes dashes to indicate the code was wrong.

Incorrect keypad lockout code entered — the display flashes dashes when the wrong unlock code is entered.

Invalid keypad code entered — the screen flashes dashes (--) when an incorrect unlock code is entered.

Compressor protection feature is engaged. The system is in a safety delay before restarting to prevent compressor damage.

Triangle symbol with exclamation mark indicating no HVAC partner found.

Heat pump needs service — the heat pump is not operating correctly and requires professional maintenance.

WiFi radio error — the wireless module is not operating and WiFi features are unavailable.

Internal memory error — the thermostat's memory has encountered an error.

Set the date and time — the time and date are not properly configured on the thermostat.

Thermostat temperature sensor error — the temperature sensor on the thermostat has encountered an error.

AC power resumed — AC power to the thermostat has been restored after a power loss.

Indoor temperature sensor error — the wired indoor temperature sensor is not connected or has a wiring short.

Outdoor temperature sensor error — the wired outdoor temperature sensor is not connected or has a wiring short.

Replace air filter (1) — the air filter needs to be replaced.

Replace air filter (2) — a second air filter needs to be replaced.

Clean humidifier tank and replace water filter — the humidifier requires maintenance.

Replace humidifier pad — the humidifier pad needs to be replaced.

Replace dehumidifier filter — the dehumidifier filter needs to be replaced.

Clean ventilator core — the ventilator core needs to be cleaned.

Clean or replace ventilator filter — the ventilator filter needs maintenance.

Replace UV bulb (1) — a UV bulb needs to be replaced.

Replace UV bulb (2) — a second UV bulb needs to be replaced.

Register online for outdoor temperature — registration is required to receive outdoor temperature data.

Register online for remote access and outdoor temperature — registration is required for full thermostat functionality.

No internet — the internet connection has been lost.

No WiFi signal — the WiFi signal has been lost and the thermostat cannot connect.

Access forbidden - additional security verification is required to access the requested resource.

Low Battery Alert — The batteries are getting low.

Critical Low Battery — The batteries are almost depleted.

WiFi not configured — WiFi connection has not been set up on the thermostat.

Loss of AC power and no DC output — the standby battery is discharged or not present, and no power is available to the system.

Loss of AC power — the standby battery is supplying power to the system.

No DC output — the power supply is not providing DC power to the system despite AC being present.

Normal operating conditions — the enclosure power supply is functioning properly with both AC and DC power available.

Auxiliary heating system is activated and running.

Auxiliary heating activates when system is in cooling mode, causing conflicting operation.

Low battery indicator that flashes for one to two months before batteries run out completely. Eventually stops flashing and stays on without flashing when batteries are almost completely dead.

Low battery warning — batteries need to be replaced soon. The icon appears approximately two months before batteries are fully depleted.

The thermostat screen is not showing any information.

Reverse Binding mode initiated for RF device pairing.

Clear option for alerts or reminders — allows permanently removing an alert from the display.

The thermostat failed to connect to the Wi-Fi network during setup.

Cooling system is activated and running.

Compressor protection feature is engaged — the system is waiting a safe amount of time before restarting the compressor after shutdown.

Compressor protection feature is engaged — the system is waiting for a safe restart time before the compressor turns back on.

Compressor protection feature is engaged — the system is waiting before restarting the compressor.

Compressor protection feature is engaged. The system is waiting before restarting to prevent equipment damage.

Cooling system activates when thermostat calls for heating, indicating reversed operation.

A high-severity alarm indicating the discharge air temperature sensor is not functioning properly or disconnected.

A medium severity alarm indicating the discharge air temperature reading is outside the configured acceptable limits.

Thermostat display shows nothing, indicating thermostat and heating/cooling system have stopped working.

Door reporting verification mode for entry door status.

A high-severity alarm indicating water has been detected in the drain pan, indicating potential condensation overflow or drain blockage.

During Wi-Fi setup, the router lost power. The thermostat cannot complete the Wi-Fi connection process.

Invalid Wi-Fi password. The thermostat cannot connect to the home network with the entered password.

Sensor error — the thermostat's temperature sensor is not functioning properly.

Communication error — the thermostat is unable to communicate with the HVAC system.

System error — a general system malfunction has been detected.

Router is not issuing an IP address to the thermostat. The thermostat cannot obtain network configuration from the router.

No internet connection. The thermostat cannot communicate with Total Connect Comfort service.

General error. A miscellaneous error has occurred during operation.

Heating system is activated and running.

Compressor protection feature is engaged — Heat On or Cool On indicators flash on the screen.

Compressor protection feature is engaged — the system is waiting 5 minutes before restarting to protect the compressor from damage.

Compressor protection feature is engaged or startup delay protection is active — the system is waiting before restarting.

An issue was detected. Contact a professional to diagnose and service your heat pump.

HVAC system fails to activate when thermostat calls for heating or cooling.

Indicates that a temperature is being held indefinitely, such as when on vacation.

Display indicator showing that the Adaptive Intelligent Recovery feature is active and the system is pre-heating or pre-cooling to reach the scheduled temperature at the scheduled time.

There is a failure of the sensor in the thermostat.

There is a failure of the sensor in the thermostat.

To receive outdoor temperature, the thermostat needs to be connected to the Internet.

Low battery indicator — the installed batteries are low and need to be replaced soon.

Battery power is low and needs replacement immediately.

There is a failure of the memory chip in the thermostat.

Sign in to the Resideo App and follow the instructions to add a thermostat.

The thermostat is connected to the network but can't reach the Internet.

The Wi-Fi signal indicator shows no connection in the upper right corner of the home screen.

A high-severity alarm indicating the pipe temperature sensor is not functioning properly or is disconnected.

A high-severity alarm indicating the pipe temperature reading is outside acceptable operating limits.

Ping mode for verifying communication with non-battery powered devices.

There was an interruption in the power to the thermostat, but it has been restored.

An alarm triggered when the fan is supposed to be on but proof of air flow is not detected for 60 consecutive seconds. The control system monitors a digital input from a current switch or differential pressure switch.

A high-severity alarm indicating no water flow is detected when the water pump or water valve should be operating.

Adaptive Intelligent Recovery is active — the system is pre-heating or pre-cooling before the scheduled time.

Emergency Heat mode is active. The red light indicates the thermostat is operating in emergency heat mode.

The wireless sensor RF network is not operating. Wireless sensor features are not available at this time.

The thermostat has not been registered to a Total Connect Comfort account or registration has been removed.

Air filter reminder — the thermostat is notifying that the air filter needs to be replaced.

Low battery warning — batteries are depleted or nearly depleted and need replacement.

Low battery warning indicator that flashes on the display when batteries are running low and need replacement.

Room ID not set or initialization mode display on startup.

A high-severity alarm indicating room temperature is moving in the opposite direction of the active system mode (heating mode but temperature decreasing or cooling mode but temperature increasing).

Room temperature is moving in the opposite direction of the system operating mode (e.g., heating but temperature dropping).

Screen lock is active — a locked key was pressed or screen is in partial lock mode.

Display indicator showing that the clock/time has not been properly set on the thermostat.

Date and time are required for features such as scheduling.

Snooze option for alerts or reminders — allows deferring an alert for 7 days without clearing it.

A high-severity alarm indicating that space temperature has dropped to dangerous levels where freezing could occur.

A high or medium severity alarm indicating the humidity sensor is not functioning properly or providing invalid readings.

A high or medium severity alarm indicating the space temperature reading is outside acceptable operating limits.

A high or medium severity alarm indicating the space temperature sensor is not functioning properly or providing invalid readings.

A high-severity alarm indicating the thermostat has lost communication with a connected Sylk device or sensor.

Temporary temperature override is active — the thermostat is holding the manually set temperature until the next scheduled time period begins.

Indicates that temperature has been temporarily changed for the current period only. The setting cancels itself at the next scheduled change.

Internal issue with thermostat memory chip.

Power was lost and the time is not able to update through Wi-Fi either because the thermostat was not registered or there is poor Wi-Fi communication.

Caution or alert message indicator on the display.

Caution or alert message indicator — the thermostat is signaling a warning or alert condition that requires attention.

A medium severity alarm indicating the thermostat's real-time clock is not synchronized or contains invalid time data.

Keypad lockout is active — the display shows 'unlock' when the keypad is locked and temperature settings cannot be changed.

The thermostat is installing a software update via Wi-Fi. The display shows the percentage of completion.

Compressor protection timer is active — the system is in a safety delay period before restarting.

A high-severity alarm indicating the water source temperature is not appropriate for the current heating or cooling operation.

The thermostat is in Wi-Fi setup mode and needs to be connected to a home network.

The thermostat has successfully connected to the Wi-Fi network.

There is a failure of the Wi-Fi module in the thermostat.

Wi-Fi has not been configured on this thermostat.

The Wi-Fi connection has been lost.

Low battery warning — batteries are low and must be replaced soon.

Critical battery failure — chronothermostat has shut down due to critically low battery.

Generic Error — a general communication or system error has occurred with the Wi-Fi connection.

Internet Failure — the chronothermostat cannot connect to the internet or Wi-Fi network.

Data Connection Made But Bliss Did Not Receive Answer — connection to network established but cloud server did not respond.

Data Received Corrupted — data received from the cloud is corrupted or incomplete.

Incorrect PIN code entered — wrong PIN was entered when attempting to unlock the chronothermostat.

Frost protection activated — room temperature has fallen below the frost protection threshold while device is off.

Chronothermostat is locked — device is in lock mode and requires PIN to unlock.

Chronothermostat is turned off — device is in off state but frost protection function remains active.

No power to the thermostat.

No power to the heating system.

No power to the cooling system.

Temperature sensor error — the thermostat cannot accurately read the current temperature.