There are a number of potential causes for ASCO solenoid failures, so they are considered complex and prone to failure. In fact, they are very simple and very reliable. Many problems are caused by something other than the valve, while others are due to misapplication or incorrect installation. ASCO solenoid valves should be checked for voltage and pressure input to begin troubleshooting. The problem may be due to inoperative control relays or pressure regulators. If the voltage and pressure checks pass, observe the valve. The reason that the direct-acting solenoid valve can not work is as follows: Low voltage or no voltage; Solenoid coil burns out; Pressure is higher than the rated pressure of the valve; There is external impurity in the valve; The valve core is stuck or the core tube is damaged. For proper operation, the solenoid valve plug must move within the core tube and contact the plunger nut when the coil is energized. A sharp metal click should be heard when energized, and the voltage supplied to the coil must be at least 85% of the rated voltage on the nameplate. If the solenoids coil voltage is correct, but without a click may indicate that the tube pressure is higher than the rated pressure of the valve, check. When troubleshooting the four-way valve control cylinder, you must follow the instructions that the valve carries. Some four-way valves require a mist lubricator to work properly. Pilot controlled four-way valves typically require full-size tubing for both pressure inlet and pressure outlet tubes. In some valves, the speed control should be limited to the cylinder connections. Because cylinder failure is usually caused by itself, it should be checked whether the following conditions exist. If the tube pressure is acceptable, external impurities may prevent the spool from moving in the core tube. If the top of the spool is struck more than a million times, the spool is swollen or cut, or the spool itself is damaged, the movement of the spool is also limited. Pilot Operated Valves may not work despite hearing a click at power-up. Flow-free conditions can be caused by insufficient pressure drop across the valve, ruptured diaphragm or damaged piston ring, blocked or restricted pilot orifice. Pilot operated and direct operated valves fail to operate due to power failure. Possible causes are: Control circuit failure; scale and other external contaminants in the valve; stuck spool or damaged core tube; broken spring. Pilot operated valves may also fail due to the following causes: Power blockages; Damaged seat or disc; Damaged diaphragm or piston; Insufficient pressure drop through the valve. Solenoid valve noise is too loud (buzzing or shocking sound) may be due to the following reasons; voltage is too low; relay fault or electronic control signal is not correct; solenoid valve parts loose; spool or plunger nut surface with external impurities ; Spring damage; system pressure is too high. Centering between piston rod and connecting load. Lack of lubrication; Wear or leak of piston cup, allowing fluid to escape in the valve; System controls external impurities therein; System overload, Low tube pressure, Hoses or fittings too small in size. If the problem is not with the cylinder, check valve.