VALVE AS 2990992 - Caterpillar

Pump 1 (30) and pump 2 (31) supply oil to main control valve (10) through ports (22) and (23). The oil flows to the various valve spools through center bypass passages (9) and (19), and parallel feeder passages (12) and (20) for use upon activation. The oil also flows to pilot pressure reducing valve (8). The valve reduces the pressure of the oil for use in the pilot circuit. The pilot oil flows to the pumps and to hydraulic lock solenoid (21). When the hydraulic lock solenoid is energized, pilot oil flows to the control solenoids. Pilot oil from the hydraulic lock solenoid (21) flows through passage (33). The pilot oil flow then divides into two flow paths. Part of the pilot oil flows through passage (34). The remainder of the pilot oil flows to passage (35) and to passage (36) to the solenoids.Oil flow from pump 1 (30) flows through parallel feeder passage (20) to boom 1 control valve (14). Oil flow from pump 2 (31) flows through parallel feeder passage (12) to boom 2 control valve (11).
Illustration 3 g06197674
Boom 1 and boom 2 control valves (BOOM RAISE position)
(3) Boom 2 cylinder extend solenoid
(5) Boom cylinder retract solenoid
(6) Port to boom cylinder head end
(7) Line relief valve (boom cylinder head end)
(9) Center bypass passage
(13) Return passage
(18) Return passage
(19) Center bypass passage
(26) Boom 1 cylinder extend solenoid
(27) Port to boom cylinder rod end
(41) Check valve
(42) Spring
(43) Port
(44) Spool
(45) Passage
(46) Port
(47) Spool
(48) Spring
(49) Passage
(50) PassageWhen the joystick for the boom is moved to the BOOM raise position, an input signal is sent to the Machine Electronic Control Module (ECM). The ECM sends an output signal to boom 2 cylinder extend solenoid (3) and boom 1 cylinder extend solenoid (26). The pilot oil from the boom 1 cylinder extend solenoid (26) enters the main control valve at port (43). The pilot oil flow from port (43) shifts spool (44) of boom 1 control valve (14) against the force of spring (42).Oil flow from pump 1 (30) in parallel feeder passage (20) flows through load check valve (41), and passage (45). The oil flows through boom 1 control valve (14). The oil then shifts valve (16) in boom drift reduction valve. Oil then flows through line (6) to the head