Answer: Common faults of heat exchangers should be inspected and maintained according to different fault phenomena. If the coil is broken and the refrigerant leaks, the air conditioning refrigeration system can be repaired by leak detection, welding repair, re-vacuumizing, Freon filling and other methods. If the heat sink is deformed, the heat sink can be reshaped to restore its original shape. When the fins are covered with dust, they can be washed with water. After cleaning the dust, the original cooling effect can be restored. The fault of fan motor can refer to the repair method of single-phase motor. For stator winding coil failure, it can be partially replaced or completely rewound. If the fan blade is stuck, the fault should be eliminated according to the different stuck parts and reasons. The bearing is damaged and should be replaced with a new one. When the insulation of the fan is damaged and there is a leakage fault, the degree of insulation damage of the motor and the cause of leakage should be checked. If the leakage phenomenon is caused by local insulation damage or shell collision, local repair can be carried out. If the insulation is seriously damaged and the area is large, a new stator winding can be rewound.