How to Check the Condition of a Solenoid Valve?
2 Answers
Methods for checking the condition of a solenoid valve: First, supply the controlled medium (pressurized liquid or gas, with the pressure value at the midpoint of the solenoid valve's operating range) to the solenoid valve. Then, energize the solenoid coil. If the controlled medium changes from open to closed or from closed to open, the solenoid valve is functioning properly; otherwise, there is an issue. A solenoid valve is an electromagnetically controlled industrial device used as an automated basic component for fluid control, acting as an actuator, and is not limited to hydraulic or pneumatic applications. Solenoid valves are categorized into three main types based on their operating principles: direct-acting solenoid valves, semi-direct-acting solenoid valves, and pilot-operated solenoid valves.
As an experienced mechanic, I'll share the inspection methods. First, disconnect the battery negative terminal to ensure safety, then visually inspect the valve for oil stains, cracks, or signs of oil leakage to rule out physical damage. Next, use a multimeter to test the resistance: the normal range is between 20 to 100 ohms; infinite resistance indicates an open circuit fault in the coil, while near-zero resistance suggests a short circuit issue. For manual testing, temporarily connect a 12-volt power supply to the coil contacts—normally you should hear a clear click or see valve movement. Start the engine in the vehicle to observe system behavior; for example, if the solenoid valve doesn't respond when the AC is turned on, the compressor might not be working. Related components like oil pipe connections can also easily affect performance, so I recommend performing a simple diagnostic every quarter to prevent larger failures.
