A: Troubleshooting steps:

1 This fault occurs during the EEV pressure equalization phase. When this alarm appears, the EEV cannot complete initialization, and the unit cannot enter cooling or dehumidification mode.

2. When this alarm occurs, first check the suction pressure and discharge pressure values in the sensor status. Based on the refrigerant type and current temperature, consult the corresponding saturation pressure-temperature chart to verify whether the pressures are too high or too low.

3. Check whether all valves in the unit are fully opened, including solenoid valves, check valves, ball valves, and indoor/outdoor unit service valves. Remove the pressure sensors and inspect them for oil blockage; clean them if necessary.

4. Connect a pressure gauge and compare its readings with the values displayed on the controller. If there is a significant deviation, it is likely that the pressure sensor is faulty. If other alarms are present at the same time, contact the manufacturer for further assistance.