Causes and troubleshooting of refrigeration solenoid valve failure

Causes and troubleshooting of refrigeration solenoid valve failure

The refrigeration solenoid valve is an industrial equipment controlled by electromagnetic, used in the industrial control system to adjust the direction, flow, speed and other parameters of the medium. What should I do if the refrigeration solenoid valve fails? A summary of the reasons and solutions for the refrigeration solenoid valve failure. I hope I can help you.

　　Fault phenomenon one: The solenoid valve does not work after being energized

Remedy: Check whether the power supply wiring is bad → rewire and connect the connector, check whether the power supply voltage is within ± working range-→ adjust the normal position range, whether the coil is unsoldered → re-weld the coil short circuit → replace the coil, and whether the working pressure difference Inappropriate → adjust the pressure difference → or replace the commensurate solenoid valve, the fluid temperature is too high → replace the commensurate solenoid valve, the main valve core and moving iron core of the solenoid valve are stuck due to impurities → clean, if the seal is damaged, replace it Seal and install the filter, the viscosity of the liquid is too high, the frequency is too high, and the life is over → replace the product

　　 Symptom 2: The solenoid valve cannot be closed

Remedy: the main valve core or the seal of the iron core is damaged → replace the seal, whether the fluid temperature and viscosity are too high → replace the solenoid valve of the opposite port, if impurities enter the valve core or movable iron core of the solenoid valve → clean, The life of the spring is reached or deformed → replace, the orifice balance hole is blocked → clean in time, the working frequency is too high or the life is reached → change the product or update the product

　　Other failure conditions:

　　 internal leakage → check whether the seal is damaged, whether the spring is poorly assembled

　　 external leakage → loose connection or seal is broken → tighten the screw or replace the seal

　　 There is noise when the power is on → The solid parts on the head are loose, tighten them.

　　 Voltage fluctuation is not within the allowable range, adjust the voltage. If the suction surface of the iron core is impurity or uneven, clean or replace it in time.

　　Example: Common faults and troubleshooting of air conditioner solenoid valve

　　 Solenoid reversing valve is an electromagnetic control switching valve for the heat pump air conditioner to switch between cooling and heating. It is a two-position four-way valve. It is composed of main valve, pilot valve and solenoid coil. It is the most complicated and precise part of the air conditioner refrigeration system except for the compressor. It is also a part that is troublesome to inspect and repair, it is difficult to judge whether it is good or bad, and it is difficult to troubleshoot. In addition to control circuit failures, common failures are valve core failure, blockage or leakage, which causes the slider to fail to move or not to move.

　　Fault phenomenon three, the solenoid valve does not change direction

　　 If the solenoid valve core or the slider cannot move, but is fixed in one position, the air conditioner cooling or heating cannot be converted mutually. Generally, the most common faults are that they can only be used for cooling but not heating. At the same time, the air conditioner is protected from blowing cold air, the outdoor unit is running, the indoor unit does not blow hot air, and it stops after displaying the fault light.

　　Fault phenomenon four, solenoid valve coil short circuit

　　 When the air conditioner is switched 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 will be burned or tripped, causing the whole machine to fail to work normally.

　　Fault phenomenon five, solenoid valve slider deformation

If the slider is deformed, even if the solenoid valve coil is energized, the spool of the pilot valve will not move, causing the slider to fail to reverse, causing gas to flow inside the valve body and forming a short cycle of high pressure gas in the compressor, causing high temperature and high pressure , Until frequent thermal protection, eventually burn out the compressor insulation layer. For the entire system, the high-pressure pressure of the shut-off valve leaks to the low-pressure end, reducing the high/low pressure difference. It often manifests as no cooling, no heating or poor effect.

　　 Failure reasons and troubleshooting methods:

　　 1. When the solenoid directional valve coil is open, short-circuited or burned out, the valve core cannot be closed, causing the slider to not move. Should be replaced.

　　 2. The solenoid valve armature is stuck and the valve core cannot move, causing the slider to not move. The valve body can be opened for cleaning and adjustment.

　　3. 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 a "Da Da" noise, causing the valve core to fail to close. The power supply should be improved.

　　 4. The solenoid valve flow direction is installed upside down, causing the valve core not to move. The flow direction should be adjusted.

　　 5. The high temperature, high pressure of the system and impurities in the machine cause the slider to deform and jam. It should be replaced.

　　 6. The valve core is attracted by the residual magnetism or the valve core is stuck, and the solenoid valve cannot be closed after the power is off. Clean and adjust, replace if no effect.

　　 7. The solenoid valve gasket is damaged or the fastening screw is loose, causing refrigerant leakage. Replace the gasket and tighten the screws.

　　 8. The capillary tube on the valve is blocked or broken; or the system leaks seriously and the slider does not move. Clean the capillary or sleeve welding with a copper tube slightly thicker than the broken capillary.

　　9. Dirt in the valve, damage to the valve seat or needle, and too small spring force, causing the solenoid valve to not close tightly. Clean and adjust or replace the spring.

　　 In addition, if the internal leakage of the reversing valve causes high-pressure refrigerant gas to leak to the low pressure side, and 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 to change the direction of the reversing valve, check the pressure of the refrigeration system or find the leakage point and fill it with refrigerant. If the slide of the four-way valve does not move or does not move properly, you can use a screwdriver to tap one end of the wooden handle when checking and judging, tap the valve body lightly, switch on or off the AC 220V power supply from time to time, repeat it several times, and hear the armature suction. When the sound is combined with the reversing sound of the gas in the valve body, it can be determined that the reversing valve basically returns to normal operation.