PowerBoss Nautilus Hi-Dump PB45HDSL, Сервисная книжка

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When de-energized this valve directs flow from the rod-end of the scrub head lift cylinder to tank.
When energized it directs regulated pressure to the rod-end of the scrub head lift cylinder.
This valve directs the flow to the scrub head lift cylinder through port BL B.
The following two main brush system solenoids receive hydraulic pressure generated by the back-
pressure of the steering system and additional back pressure provided by an orifice located just before
the pressure inlet of the power steering unit (a total of approximately 700 psi). The power steering unit
is powered by the rear auxiliary pump which has a displacement of .40 cu. In./rev. and supplies a
nominal flow of 4.2 gpm.
Hydraulic fluid controlled by these two scrub brush valves enters the manifold through PORT P1.
REDUCING VALVE RV3 in port 4.1 limits the hydraulic pressure to the piston-end of the scrub head lift
cylinder to a maximum of 450 psi.
SOLENOID VALVE SV6 (Main brushes up-locked) in port 3.1 is a 2-position 2-way normally-open control
valve.
When de-energized this valve allows flow into the piston-end of the scrub head lift cylinder while
preventing flow out from the piston-end of the scrub head lift cylinder (scrub head raise and lock).
When energized this solenoid allows a maximum of 450 psi fluid flow (from reducing valve RV3) into and
out from the piston-end of the scrub head lift cylinder.
This valve directs the flow to and from the piston-end of the scrub head cylinder through port BL A.
Location and operation of the individual squeegee hydraulic valves:
The two solenoids that control squeegee functions receive hydraulic pressure from the back-pressure of
the power steering unit (a total of approximately 700 psi). The power steering unit is powered by the
rear auxiliary pump which has a displacement of .40 cu. In./rev. and supplies a nominal flow of 4.2 gpm.
Hydraulic fluid that powers the squeegee lift system enters the manifold through PORT P1.
Pressure relief is provided by the pressure relief valve in the power steering unit which allows a
maximum pressure of 1200 psi.
SOLENOID VALVE SV7 (Squeegee up-down) in port 1 is a 2-position 4-way directional control valve.
When de-energized this valve directs pressurized fluid to the piston-end of the squeegee lift cylinder
while directing the fluid from the rod-end of the squeegee lift cylinder to tank through port T1.
(Squeegee raised).
When energized it directs pressurized fluid to the rod-end of the squeegee lift cylinder while directing
the fluid from the piston-end of the squeegee lift cylinder to tank through port T1. (Squeegee lowered).
CHECK VALVE CV2 in port 2 is a pilot-operated check valve that holds the squeegee in the raised position
when the system is off.
When the rod-end of the squeegee lift cylinder is pressurized the check valve is held open allowing the
squeegee to lower.