Repair and Processing Technology of DC Solenoid Valves
Small and medium-sized cooling equipment generally uses immediate-type solenoid valves, which often experience the following common faults.
(1) Burned-out Solenoid Coil The main symptom is that the valve core does not move when plugged in, the magnet coil housing has no airflow, and a short circuit is detected by a meter. The burned-out area can be welded back together. If the burning is severe, the same type of solenoid coil should be replaced.
(2) Stuck Valve Core In this case, the solenoid valve has no open or closed position. If the gas solenoid valve is stuck in the closed position, the low voltage is negative, and there is no refrigeration cycle; if it is stuck in the open position, the high and low pressures quickly equalize after shutdown, which can easily lead to liquid slugging when starting the gas solenoid valve. Cleaning can be performed to remove the obstruction.
(3) Loose Closure After shutting down the refrigeration compressor, touch the solenoid valve with your hand. If the valve body is cold and you can hear a swirling sound inside the valve, it indicates that the solenoid valve is not tightly closed, and the refrigerant is still flowing. The possible causes include dirt inside the valve, damage or burnt-out of the high-pressure valve or valve needle, or insufficient torsion spring force. The corresponding procedures are to remove dirt from the valve, clean the high-pressure valve and valve needle, and adjust or replace the torsion spring.
(4) Oil or dirt blockage: During operation, if the solenoid valve surface is frosted or covered with frost, it indicates blockage. The valve body can be disassembled to clean out any foreign objects or oil stains.
(5) "Clicking" vibration sound when plugged in: The reasons for the "clicking" vibration sound when the solenoid valve is plugged in are as follows: The power supply voltage is too low, and the power supply voltage should be adjusted to restore it; The pressure difference between the inlet and outlet of the solenoid valve is too high, so that the coil cannot be attracted. Check whether the heat dissipation of the cooler is good, whether there is gas in the system, and clean it thoroughly; The installation angle of the solenoid valve is reversed with the general direction of refrigerant flow, and it should be reinstalled; The coil is stuck or damaged, and the valve body can be opened to clean or the valve core can be replaced; The short-circuit fault magnetic core is broken and the lead wire is broken, and the short-circuit fault magnetic core component should be replaced.
