COMPONENT OPERATION / Pump Device REGULATOR FOR FAN PUMP The regulator is provided on the top of the fan pump and control the fan pump delivery flow rate. Pump delivery flow rate is controlled as flow rate control pressure from fan pump control solenoid valve (17) increases or decreases. Own pump delivery pressure P3 is routed to compensating piston (1), spool (2) and the small chamber in servo piston (15) all the time. As fan pump control solenoid valve (17) is activated, pilot pressure Pr from the pilot pump is reduced and acts on pilot piston (22) as flow control pressure Pi. 17 Pr To Fan Motor Pi 2 22 1 P3 15 Pilot Pump T1J1-03-01-013 Fan Pump T3-1-12