Carrier 38AP Air Handler

This alarm indicates that Compressor 1 on Circuit A is stuck in the 'on' state. All compressor outputs are de-energized, but head pressure control remains active. A manual reset is required.

This alarm signifies that Compressor 2 on Circuit A is stuck in the 'on' position. All compressor outputs are de-energized, but head pressure control remains active. Manual reset is necessary.

This alarm indicates that Compressor 3 on Circuit A is stuck in the 'on' position. All compressor outputs are de-energized, but head pressure control remains active. A manual reset is required.

This alarm indicates that Compressor 1 on Circuit B is stuck in the 'on' position. All compressor outputs are de-energized, but head pressure control remains active. Manual reset is necessary.

This alarm indicates that Compressor 2 on Circuit B is stuck in the 'on' position. All compressor outputs are de-energized, but head pressure control remains active. Manual reset is necessary.

This alarm indicates that Compressor 3 on Circuit B is stuck in the 'on' position. All compressor outputs are de-energized, but head pressure control remains active. Manual reset is necessary.

The supply air thermistor has failed. The unit will shut down automatically. The alarm can be reset automatically once the thermistor is functioning correctly.

The return air thermistor has failed. The unit will shut down automatically. This alarm can be reset automatically when the thermistor is functioning correctly.

The ambient temperature is too high, or the cooling fan has failed. The system is overheating.

The system is not receiving updates for the return air temperature. The unit will shut down. This alarm resets automatically upon receipt of temperature updates.

The system is not receiving updates for the supply air temperature. The unit will shut down. This alarm resets automatically when updates are received.

An Electronic Programming Module (EPM) with corrupted data has been installed, or the EPM is blank. A factory reset is needed.

This alert indicates a general failure of Compressor 1 on Circuit A. The affected compressor has been shut down. A manual reset is required.

This alert signifies a general failure of Compressor 2 on Circuit A. The affected compressor has been shut down. A manual reset is required.

This alert indicates a general failure of Compressor 3 on Circuit A. The affected compressor has been shut down. A manual reset is required.

This alert indicates a general failure of Compressor 1 on Circuit B. The affected compressor has been shut down. A manual reset is required.

This alert indicates a general failure of Compressor 2 on Circuit B. The affected compressor has been shut down. A manual reset is required.

This alert indicates a general failure of Compressor 3 on Circuit B. The affected compressor has been shut down. A manual reset is required.

The output current has exceeded the set CURRENT LIMIT. The drive is reducing output frequency to lower the current. If this persists, it may lead to a CURRENT OVERLOAD fault.

Communication between the scrolling marquee and the Main Base Board (MBB) has been lost. If the communication loss is internal to the MBB, the unit will shut down or not start. The alert resets automatically once communications are re-established.

Invalid data has been entered, or an invalid command was attempted. This indicates a user input error.

The user data and OEM defaults in the EPM are corrupted. Restore factory defaults or replace the EPM.

The control module is not communicating with the master controller. This warning indicates communication has been lost for more than 5 minutes. The unit will typically continue to run if the communication loss is external to the module.

The compressor has cycled on and off too frequently, running for less than one minute per cycle. This warning is active if the compressor has short cycled more than 48 times in 24 hours and the 'Short Cycling' DIP switch is OFF.

The module detects an issue with the scroll NTC thermistor, indicating it may be open or shorted. This warning is not applicable to 38AP units.

The line voltage is too high, the deceleration rate is too fast, or there is an overhauling load. Adjust settings or check voltage.

The watchdog timer has timed out, indicating that the serial link has been lost. Check connections and communication settings.

The drive has failed three start attempts and requires a manual reset to clear the fault lockout.

The motor's PTC circuit has exceeded a high resistance limit, indicating high motor temperature. This will open the M2-M1 contacts, stopping the compressor. The system will attempt to reset after 30 minutes if the temperature normalizes. Five consecutive alerts will cause a lockout.

The motor PTC thermistor circuit shows a resistance value indicating it is open or shorted. This stops the compressor. The system attempts to reset after 30 minutes if the thermistor returns to a normal resistance range. A lockout occurs after 6 hours of the fault condition.

The compressor is locked out due to excessive short cycling. This occurs when the 'Short Cycling' DIP switch is ON and the compressor cycles on and off too frequently (less than 1 minute runtime) within a 24-hour period. A power cycle is required to clear the lockout.

The scroll NTC circuit has detected a temperature condition indicating potential overheating. This will temporarily stop the compressor. This code is not used for troubleshooting on 38AP units.

A phase is missing in one of the three leads supplying power to the compressor. This will stop the compressor. The system will attempt to reset after 5 minutes if the phase condition is corrected. Lockout occurs after 10 consecutive alerts.

The phase sequence of the incoming power to the compressor is incorrect. This will immediately stop the compressor and lock it out after one alert. A power cycle is required to clear the lockout.

The voltage supplied to the control module (on T2-T1 terminals) is below 18 VAC for more than 5 seconds. This will stop the compressor. The system will attempt to reset after 5 minutes if the voltage is between 18 and 30 VAC. This alert does not cause a lockout.

The controller is operating correctly but is the only device detected on its network segment. This may indicate a network configuration issue or that other devices are offline.

The controller is indicating normal operation but has entered a 5-minute auto-restart delay following a system error. The controller will attempt to restart automatically after this delay.

This indicates that the controller has just been formatted or reset to its factory defaults. Control programs may need to be reloaded.

The controller has halted program execution due to repeated system errors or control program failures. This indicates a significant issue requiring investigation.

The controller is in the bootloader mode, actively transferring firmware. The unit will restart automatically once the transfer is complete.

The controller's startup process has been aborted, and it is currently in the bootloader mode. This may occur after a firmware update or a critical error.

The controller is in a 10-second recovery period following a power disturbance (brownout). It is preparing to resume normal operation.

The controller has detected a significant voltage drop (brownout). It has entered a recovery state and will attempt to restart after a delay.

The control module has detected an internal fault. This requires a module reset by removing power, and potentially replacing the module if the issue persists.

This alert indicates that Circuit A's compressor is currently unavailable or has been shut down. Manual intervention is required to reset.

This alert signifies that Circuit B's compressor is not available or has been shut down. A manual reset is needed to clear this alert.

This alert means the compressor on Circuit A, Compressor 1, is rapidly cycling on and off (chattering). The affected compressor is shut down to prevent damage. A manual reset is needed.

This alert indicates Compressor 2 on Circuit A is rapidly cycling on and off (chattering). The compressor has been shut down to prevent damage. Requires a manual reset.

This alert signifies that Compressor 3 on Circuit A is rapidly cycling on and off (chattering). The affected compressor has been shut down to prevent damage. Requires a manual reset.

This alert signifies that Compressor 1 on Circuit B is rapidly cycling on and off (chattering). The affected compressor has been shut down to prevent damage. Requires a manual reset.

This alert signifies that Compressor 2 on Circuit B is rapidly cycling on and off (chattering). The affected compressor has been shut down to prevent damage. Requires a manual reset.

This alert signifies that Compressor 3 on Circuit B is rapidly cycling on and off (chattering). The affected compressor has been shut down to prevent damage. Requires a manual reset.

The return gas thermistor for Circuit A has failed. This circuit will shut down. The alert resets automatically once the thermistor is functioning correctly.

The return gas thermistor for Circuit B has failed, causing this circuit to shut down. The alert resets automatically when the thermistor is functioning correctly.

The outside air thermistor has failed. Outside air temperature reset functionality will be disabled, but the unit will continue to run under normal set point control. Outdoor ambient lockout is also disabled. The alert resets automatically when the thermistor functions correctly.

The space temperature thermistor has failed. Space temperature reset functionality will be disabled, and the unit will run under normal set point control. The alert resets automatically when the thermistor functions correctly.

The space temperature offset sensor has failed. This offset function will be disabled, but the unit will continue to run normally without the offset. The alert resets automatically when the sensor functions correctly.

The discharge pressure transducer for Circuit A has failed, causing Circuit A to shut down. The alert resets automatically once the transducer is functioning correctly.

The discharge pressure transducer for Circuit B has failed, causing Circuit B to shut down. The alert resets automatically once the transducer is functioning correctly.