Fujitsu Air Water

The LED on the outdoor unit flashes once, indicating a problem with the serial forward communication. This means data is not being sent correctly from one part of the system to another.

The LED on the outdoor unit flashes two times. This indicates an issue with the discharge thermistor, which measures the temperature of the refrigerant as it leaves the compressor.

The LED on the outdoor unit flashes three times. This indicates a problem with a pressure switch in the system, which monitors refrigerant pressure.

The LED on the outdoor unit flashes four times. This indicates an error with the heat-exchange thermistor located at the outlet of the heat exchanger.

The LED on the outdoor unit flashes six times. This indicates an issue with the thermistor associated with the electronic expansion valve.

The LED on the outdoor unit flashes seven times. This indicates a problem with the outdoor temperature thermistor, which measures the ambient air temperature.

The LED on the outdoor unit flashes eight times. This indicates a problem with the thermistor that monitors the compressor's temperature.

The LED on the outdoor unit flashes nine times. This indicates an error with the Transistor Printed Circuit Board (PCB), which is typically part of the inverter module controlling the compressor.

The system detects an issue with the outdoor temperature sensor, meaning it cannot accurately measure the ambient outdoor temperature.

The hydraulic unit's green LED flashes once and the red LED flashes once, indicating a problem with communication between the indoor hydraulic unit and the outdoor unit. This means the two main parts of your heat pump system are not communicating properly.

The LED on the outdoor unit flashes 11 times. This indicates a serious and persistent error related to the refrigerant discharge temperature, leading to a permanent system stoppage.

The LED on the outdoor unit flashes 12 times. This indicates a critical and persistent error with the compressor's temperature, leading to a permanent system shutdown.

The LED on the outdoor unit flashes 14 times. This indicates a critical and persistent error in detecting the compressor's rotational position, leading to a permanent system stoppage. (Note: Only applies to 3-phase outdoor units.)

The LED on the outdoor unit flashes 15 times. This indicates a critical and persistent error during the compressor's startup sequence, resulting in a permanent system stoppage.

The LED on the outdoor unit flashes 16 times. This indicates a critical and persistent error with outdoor fan motor 1, leading to a permanent system stoppage.

The LED on the outdoor unit flashes 17 times. This indicates a critical and persistent error with outdoor fan motor 2 (if present), leading to a permanent system stoppage.

The LED on the outdoor unit flashes 18 times. This indicates a serious and persistent error with the inverter component in the outdoor unit, which controls the compressor speed, leading to system stoppage.

The LED on the outdoor unit flashes 20 times. This indicates an abnormally low pressure condition in the system, potentially causing the unit to stop operating.

The green LED on the hydraulic unit flashes twice and the red LED flashes three times. This indicates a connection error where the system detects a forbidden series connection.

The LED on the outdoor unit flashes 23 times. This indicates a problem with the discharge pressure sensor, which measures the pressure of the refrigerant leaving the compressor.

The LED on the outdoor unit flashes 24 times. This indicates a problem with the suction pressure sensor, which measures the pressure of the refrigerant returning to the compressor.

The system detects an issue with the flow sensor in the mixing circuit, indicating it cannot accurately measure water flow.

The hydraulic unit's green LED flashes three times and the red LED flashes once. This indicates that the power supply to the indoor unit is abnormal or unstable.

The hydraulic unit's green LED flashes three times and the red LED flashes twice. This indicates a communication problem between the controller PCB and the interface PCB inside the unit.

The system detects an issue with the flow sensor specific to the heat pump circuit, meaning it cannot accurately measure water flow through the heat pump.

The hydraulic unit's green LED flashes four times and the red LED flashes once. This means there is an issue with the signal that controls or measures the heat pump's heating/cooling capacity, potentially due to an open circuit or a short circuit.

The hydraulic unit's green LED flashes four times and the red LED flashes twice. This indicates a fault with the heat-exchange thermistor located within the hydraulic unit.

The system detects an issue with the return temperature sensor in the heat pump circuit, preventing accurate measurement of the water returning to the heat pump.

The system detects an issue with the domestic hot water (DHW) sensor 1, meaning it cannot accurately measure the temperature of the hot water.

The system detects an issue with room sensor 1, indicating it cannot accurately measure the room temperature in the primary zone.

The hydraulic unit's green LED flashes six times and the red LED flashes once. This indicates that the power supply to the outdoor unit is experiencing an abnormality.

The hydraulic unit's green LED flashes six times and the red LED flashes twice. This indicates a fault with the main Printed Circuit Board (PCB) in the outdoor unit.

The hydraulic unit's green LED flashes six times and the red LED flashes three times. This indicates an error with the inverter component in the outdoor unit, which controls the compressor speed.

The hydraulic unit's green LED flashes six times and the red LED flashes four times. This error indicates a problem with the active filter in the outdoor unit, which helps maintain power quality.

The system detects an issue with room sensor 2, indicating it cannot accurately measure the room temperature in the secondary zone.

The hydraulic unit's green LED flashes six times and the red LED flashes seven times. This signifies that the outdoor unit experienced a brief power interruption, causing it to enter a protective shutdown.

The hydraulic unit's green LED flashes six times and the red LED flashes eight times. This indicates a problem with a magnetic relay within the outdoor unit, which controls various electrical circuits.

The hydraulic unit's green LED flashes seven times and the red LED flashes once. This indicates an issue with the discharge thermistor, which measures the temperature of the refrigerant discharged from the compressor.

The hydraulic unit's green LED flashes seven times and the red LED flashes twice. This indicates a problem with the thermistor that monitors the compressor's temperature.

The hydraulic unit's green LED flashes seven times and the red LED flashes three times. This indicates an error with a heat-exchange thermistor, specifically at the outlet or an intermediate point in the system.

The hydraulic unit's green LED flashes seven times and the red LED flashes four times. This indicates a problem with the outdoor temperature thermistor, which measures the ambient air temperature.

The hydraulic unit's green LED flashes seven times and the red LED flashes seven times. This indicates an error with the thermistor monitoring the temperature of the heat sink in the outdoor unit.

The hydraulic unit's green LED flashes seven times and the red LED flashes eight times. This indicates an issue with the thermistor associated with the expansion valve.

The system detects a short circuit on the BSB (Building System Bus) communication line, which can disrupt communication between connected system components.

The hydraulic unit's green LED flashes eight times and the red LED flashes four times. This indicates a problem with the current sensor in the outdoor unit, which monitors electrical current flow.

The hydraulic unit's green LED flashes eight times and the red LED flashes six times. This indicates an error with either a pressure sensor or a pressure switch in the system.

The hydraulic unit's green LED flashes nine times and the red LED flashes four times, or the outdoor unit LED flashes 13 times. This signifies that the system has detected an excessive electrical current, leading to a protective shutdown.

The hydraulic unit's green LED flashes nine times and the red LED flashes five times. This indicates a problem with detecting the compressor's rotational position or an issue during the compressor's startup sequence.

The hydraulic unit's green LED flashes nine times and the red LED flashes seven times. This indicates a problem with the motor of outdoor fan 1.

The hydraulic unit's green LED flashes nine times and the red LED flashes eight times. This indicates a problem with the motor of outdoor fan 2 (if present).

The hydraulic unit's green LED flashes ten times and the red LED flashes once. This indicates that the system has activated its protection due to an excessively high refrigerant discharge temperature from the compressor.

The hydraulic unit's green LED flashes ten times and the red LED flashes three times. This signifies that the compressor's internal temperature has exceeded safe limits, triggering a protective shutdown.

The hydraulic unit's green LED flashes ten times and the red LED flashes four times. This indicates a general pressure fault within the outdoor unit, which could be either too high or too low.

The hydraulic unit's green LED flashes ten times and the red LED flashes five times. This indicates an abnormally low pressure condition in the system.

The hydraulic unit's green LED flashes ten times and the red LED flashes nine times. This indicates that the system is drawing too much electrical current, triggering a protective overload shutdown.

The green LED is continuously lit, and the red LED is off. This indicates that the outdoor unit is currently undergoing a defrosting cycle to remove ice buildup from its coil. This is a normal operating mode, not a fault.

The hydraulic unit appears to have no power, with no display or indicator lights. This suggests an issue with the power supply to the indoor unit.

The outdoor unit appears to have no power or is not responding. This suggests an issue with the power supply to the outdoor unit.

Both green and red LEDs are continuously flashing, alternating on and off every second. This is not an error but an indication that the heat pump is performing a 'pump down' operation, typically to recover refrigerant for maintenance or to protect the system.