To protect the compressor against overload, when the system is operating
in heating, the temperature of the internal coil is monitored. High temperatures in the internal coil in the heating mode indicate that the compressor is operating at high discharge pressure.
The protection logic is as follows:
- When the temperature in the internal coil sensor reaches 60 ° C, the board switches off the outdoor unit fan. Without flow in the heat exchanger (which is acting as an evaporator) the suction pressure will be reduced and, as a consequence, the discharge pressure will also be reduced.
- If, even without external ventilation, the internal coil temperature continues to rise and reaches 68 ° C, the compressor will shut down and an alarm will be generated;
- After the compressor has been switched off, the temperature of the internal coil will drop and, when it reaches 50 ° C, the board will turn the external fan on;
- When it reaches 42ºC, the compressor will be turned back on;
