The fan is controlled by the medium voltage switch in the pressure switch. For example, when the pressure reaches 1.47, the action of the medium voltage switch makes the condensing fan run at high speed.
After the air conditioner is turned on, the compressor starts to work. After it compresses the condensate into liquid, the temperature of the condensate will rise. If this part of heat is not discharged, the refrigeration work of the next cycle cannot be carried out. So it must be dispersed into the atmosphere through the radiator, and the natural heat dissipation effect of the radiator is very poor. So turn on the fan to force heat dissipation.