According to Omega Engineering, solenoid valves "are control units which, when electrically energized or de-energized, either shut off or allow fluid flow." Solenoids are often used in facilities as well as equipment where the flow of water needs to be controlled automatically. There are times when solenoid valves do not work properly. By troubleshooting the valve, you will be able to assess the situation and rectify it.
Check the solenoid with a voltmeter to ascertain whether there is an electrical signal to the solenoid. Failure to complete the solenoid's AC current will burn out its coil.
Check the covers of the solenoid. If the cover is loose or absent, it can allow the entry of foreign substances such as iron or chips of metal. If these metal pieces get inside the solenoid, they can interfere with the magnetic field inside the solenoid. This will cause the solenoid to function improperly. Clean out the solenoid and reattach the cover or covers.
Replace the pin if the push rod is no longer the proper length to actuate the valve. The replacement pins and instructions are available through the manufacturer. A faulty pin can be the result of the push rod being worn down over time.
Examine the springs of the solenoid. The spring is located above the diaphragm of the solenoid valve. It is what opens and closes the diaphragm of the valve, allowing or cutting off of water.
Examine the current running to the solenoid. If not enough power or too much power is running to the solenoid, then it can cause the solenoid to not run properly. The manufacturer specifies the optimum voltage; a voltmeter can measure the voltage of the solenoid valve.