Advance acoustic 56514925, Service Manual

Page: 170 / 260

Scrub System 170 Service Manual – Advance 7765 / Nilfisk CR1500
Scrub Deck Cylinder
The
Scrub Brush Solenoid (6)
,
Scrub Brush Solenoid (8)
and
Scrub Brush Lock Up Solenoid (9)
in the cylinder
control valve control the scrub deck hydraulic cylinder to lower and raise the scrub deck, and determine
which of the two scrub pressures is used. The
Ignition Switch
must be on for the scrub deck cylinder to lower
and raise the scrub deck.
• Scrub Deck Down at Normal Scrub Pressure
When the
Ignition Switch
is on, the
Scrub Brush Lock Up Solenoid (9)
is energized. This connects both ports
on the scrub deck cylinder with the hydraulic return line to the reservoir. The equal pressure on both
ends of the scrub deck cylinder allows the scrub deck to lower to the floor under its own weight.
• Scrub Deck Down at High Scrub Pressure
When the
Drive Pedal Forward Sensor
switches the
Forward Relay R4
contacts to the
87
(
Lower
) position,
the
Scrub Brush Switch
is set to the
Lower
position and the
Brush Pressure Switch
is set to the heavy scrub
(“two-bar”) position, the
Scrub Brush Lock Up Solenoid (9)
and
Scrub Brush Solenoid (8)
are energized. This
connects the top port on the scrub deck cylinder to the 270 psi oil from the power steering unit. This
presses the scrub deck downward to its heavy scrub pressure setting. Note that the
Brush Pressure Switch
will light when in the heavy scrub (“two-bar”) position.
• Scrub Deck Up
When the
Drive Pedal Forward Sensor
switches the
Forward Relay R4
contacts to the
87a
(
Raise
) position,
the
Scrub Brush Solenoid (6)
will be energized and the
Scrub Brush Solenoid (8)
will be de-energized. This
connects the bottom port on the scrub deck cylinder to the 270 psi oil from the power steering unit to lift
the scrub deck upward to its retracted position.
Also refer to the
Scrub System Hydraulic Diagrams
section.