1.4 The coil of the way reversing valve is open circuit, short circuit or the voltage does not meet the performance requirements of the coil, causing the spool of the pilot valve to fail to act;

2. Due to external reasons, the pilot valve part is deformed, causing the valve core to not move;

3. The capillary of the pilot valve is deformed or blocked, the flow is insufficient, and the pressure difference required for reversing cannot be formed;

4. The main valve body is deformed, and the piston part is stuck and cannot move;

5. The refrigerated oil is deteriorated or the debris enters the system, and the piston of the 4 way reversing valve is stuck;

6.4 When the way reversing valve is welded, the temperature is too high, and the internal parts are thermally deformed and cannot move;

7. The refrigerant leaks in the air-energy heat pump system, the refrigerant circulation is insufficient, and the pressure required for commutation cannot be achieved;

8. The compressor temperature is too high, the compressor cannot be well cooled due to refrigerant leakage and other reasons, and the exhaust temperature is too high, causing the internal parts of the 4 way reversing valve to be deformed and stuck or the commutation fails.