Flow control valves regulate fluid flow. This can control the speed of actuators and other components in a hydraulic system. The valves can be operated in a number of ways. Some valves have an external control, some valves operate electro-mechanically and some valves are simply a section of hydraulic line with a smaller inside diameter than that of the rest of the hydraulic system. But, no matter what the type of valve it is, they all work by adjusting the fluid flow that passes through them.
Depressurize the hydraulic system by turning off the system pumps.
Remove the electrical power from the system pumps, if applicable. Do this by disconnecting the pump's power connector or pulling its circuit breaker. Certain mechanically driven pumps, such as engine-driven pumps, may not have any electrical connectors.
Position the new valve where it will be installed. The fittings on the valve should be plugged and the ends of the pipes or tubing it will connect to should be capped. Make sure the valve is in its proper orientation. You may have to consult a hydraulic schematic if you are unsure of which direction fluid should travel through the valve.
Uncap the valve fittings and unplug the connecting lines.
Screw the nuts from the hydraulic lines onto the fittings on the flow control valve. Tighten the nuts to their manufacturer-specified torques.
Check the hydraulic system fluid level and refill it with new fluid as needed.
Connect any electrical connectors, push in any pump circuit breakers and then pressurize the system with the hydraulic pumps.
Check the fittings and hydraulic lines at and near the valve for leaks.