- Make sure that the high-pressure switch connector has been properly connected.
- If the high-pressure switch is properly connected, connect a high-pressure gauge to the high-pressure outlet port and monitor the pressure during operation to check the pressure when the high-pressure switch is activated. Check valve failure is likely if the pressure is less than 3.3 MPa. The following describes checks to be made when the pressure is high.
- During cooling, check whether the outdoor unit heat exchanger is clogged. Remove anyforeign material that prevents ventilation.
- During cooling, check whether an air short blockage has occurred in the outdoor unit. The system is operating normally unless the temperature around the outdoor unit is excessively high.
- During cooling, check for outdoor fan failure. Check whether the screws securing the fan are loose and whether the fan connector in the outdoor unit PCB is properly connected.
- During heating, check whether the air filters in the indoor unit are clogged. If clogged, clean the filters.
- During heating, check whether an air short blockage has occurred in the indoor unit. The system operates normally unless the temperature around the indoor unit is excessively high.
- During heating, check for indoor fan failure.
- Check whether the refrigerant circuit is clogged. Check that all service valves are closed.Check whether welded locations are clogged.
- Check for mechanical valve failure. Check whether the mechanical valves make a clattering sound when the power is reset. Since the mechanical valve in the indoor unit is in a location that makes aural inspection difficult, use an electric means to check. Check that the connector pin of the mechanical valve on the PCB outputs 4 V. In addition, check that the coil resistance of the mechanical valve is several tens of Ω.
- Check for solenoid valve kit failure. Removing a coil that is on will result in a clicking sound.Also, removing a coil that is off will not produce such a sound.
- Check whether too much refrigerant has been charged. Too much refrigerant has been charged if the sub-cool temperature of the condenser is 15ºC or more.