- 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 any foreign 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 Ohm (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 15°C or more.
- Check whether the wiring from the solenoid valve kit is actually connected to the different indoor unit or not.
- The system is that the multiple indoor units are connected at only one solenoid valve kit and also multiple remote controllers are connected. Check whether "installation of the common use solenoid valve kit" from a PC has been made or not. (Confirmation from the address setting software of a PC)