Solenoid valve is a kind of automatic valve, because it has very high efficiency, easy to use and low price, so it is widely used in daily life and production. But it is also inevitable that there will be problems and failures, so it is also very important to troubleshoot and solve the failure of the solenoid valve.
1. Fault phenomenon of electromagnetic reversing valve
（1） Solenoid valve does not change direction
If the solenoid valve core or slider cannot move and is fixed in one position, the cooling or heating of the air conditioner cannot be switched to each other. Generally, the most common faults are that it can only cool but not heat. At the same time, it causes the air conditioner to protect against blowing cold wind, the outdoor unit is running, but the indoor unit does not blow hot air, and the fault light is displayed and then shuts down.
（2） Solenoid valve coil short circuit
When the air conditioner switches to heating operation, the solenoid valve coil is short-circuited and the current is too large. In severe cases, the fuse on the main control board is burned or tripped, causing the whole machine to fail to work normally.
（3） Solenoid valve slider deformation
If the slider is deformed, even if the solenoid valve coil is energized, the pilot valve core will not move, which will cause the slider to not reversing in place, causing gas to leak inside the valve body, and high-pressure gas in the compressor to form a short cycle, causing high temperature and high pressure. , until frequent thermal protection, and finally burn out the insulation layer of the compressor. For the whole system, the high pressure pressure of the stop valve leaks to the low pressure side, so that the high/low pressure difference is reduced. It often manifests as no cooling, no heating or poor effect.
2. Common faults and troubleshooting methods of electromagnetic reversing valve
（1）The wiring head of the solenoid valve is loose or the thread ends fall off, the solenoid valve cannot be powered, and the thread ends can be tightened.
（2） The coil of the solenoid valve is burnt out. The wiring of the solenoid valve can be removed and measured with a multimeter. If the circuit is open, the coil of the solenoid valve is burnt out. The reason is that the coil be affected with damp, which will cause poor insulation and magnetic flux leakage, which will cause excessive current in the coil and be burned down. Therefore, rainwater should be prevented from entering the solenoid valve. In addition, the spring is too hard, the reaction force is too large, the number of turns of the coil is too small, and the suction force is not enough, which can also cause the coil to burn out. For emergency treatment, the manual button on the coil can be turned from "0" to "1" during normal operation to open the valve.
（3）The armature of the solenoid valve is stuck, the valve core cannot move, and the slider does not move. The valve body can be opened for cleaning and adjustment.
（4）When the power supply voltage is lower than the rated value of the solenoid valve, the pressure difference between the inlet and outlet of the solenoid valve exceeds the valve opening capacity. At this time, the valve often emits "da da" noise, causing the valve core to fail to close. The power supply should be improved.
（5）The flow direction of the solenoid valve is reversed, causing the valve core to not move. The flow direction should be adjusted.
（6） The high temperature and high pressure of the system and impurities in the machine will cause deformation and jamming of the slider. should be replaced as well.
（7）The residual magnetism attracts the valve core or the valve core is stuck, and the solenoid valve cannot be closed after power failure. Clean and adjust, replace if no effect.
（8） The gasket of the solenoid valve is damaged or the fastening screws are loose, causing refrigerant leakage. Replace the gasket and tighten the screws.
（9）The capillary on the valve is blocked or broken; or the slider does not move due to serious leakage of the system. Clean the capillary or use a copper tube that is slightly thicker than the broken capillary to weld.
（10）There is dirt in the valve, the valve seat or needle is damaged, and the spring force is too small, causing the solenoid valve to not close tightly. Clean and adjust or replace spring.
In addition, if the internal leakage of the reversing valve causes the high-pressure refrigerant gas to leak to the low-pressure side, and the normal pressure cannot be established at both ends of the reversing valve piston, the reversing valve should be replaced. If the pressure difference of the refrigeration system is too large and the reversing valve cannot be reversed, it is necessary to check the pressure of the refrigeration system or find the leak point and fill it with refrigerant. If the slider of the four-way valve does not move or does not move in place, you can use the end of the wooden handle of a screwdriver to check and judge, tap the valve body lightly, and turn on or off the AC 220v power supply from time to time, repeat several times, and hear the armature sucking When there is a chorus sound and gas reversing sound in the valve body, it can be judged that the reversing valve has basically returned to normal work.selected, and the fast type is selected for large diameters.
4. Economy
There are many types of solenoid valves at present, so choose the most economical one after meeting the above conditions.