A flow control system for an irrigation sprinkler can include a service valve having an inlet, a first fluid port, a second fluid port, a third fluid port, and/or a valve piston having a valve piston inlet and a valve piston outlet. The system can include a pilot valve and a vent line. The system can include a filter in fluid communication with the inlet of the service valve. The valve piston can be configured to move vertically with respect to the first, second, and third fluid ports between first, second, and third valve positions.