Nilfisk-Advance 7765 Service Manual page 69

Service Manual – Advance 7765 / Nilfisk CR1500
The
Scrub Brush Solenoid (6)
and
Brush Solenoid (8) Scrub Brush
are part of the
Lock Up Solenoid (9)
located below
Cylinder Control Valve
the access panel on the floor of the
Operator compartment.
The hydraulic hose from
on the
Cylinder Control Valve
connected to the lower port on the
scrub deck cylinder.
The hydraulic hose from
on the
Cylinder Control Valve
connected to the upper port on the
scrub deck cylinder.
Troubleshooting
Problem
Scrub deck motors
not running.
Unable to change
scrub brush rotation
direction.
,
Scrub
Port C1
Scrub Brush
is
Lock Up
Solenoid (9)
Cylinder
Control Valve
Port C2
Manifold Block
is
Port C1 to
Bottom Port
on Scrub Deck
Hydraulic Cylinder
Cause
No voltage to the Normal
Rotation Brush (4) solenoid
in the Main Control Valve.
Normal Rotation Brush (4)
solenoid in the Main Control
Valve not operating (stuck
open).
No voltage to the Reverse
Rotation Brush (3) solenoid
in the Main Control Valve.
Reverse Rotation Brush (3)
solenoid in the Main Control
Valve not operating.
Scrub Brush
Solenoid (6)
Correction
1. Check circuit breaker CB7 and reset if necessary.
2. Check that the Drive Pedal Forward Relay is
sending 12 VDC to the Forward Relay coil when
the drive pedal is moved to the forward position.
3. Check the continuity through the Forward Relay
and Scrub Brush Switch to the Normal Rotation
Brush (4) solenoid. Repair the wiring, or replace
the relay and/or switch as necessary.
1. Check the coil resistance of the Normal Rotation
Brush (4) solenoid. If not 7.2 ohms ±10%, replace
the coil.
2. If the coil resistance is within spec, check for
binding or a mechanical problem. Repair or
replace the valve as necessary.
1. Check circuit breaker CB7 and reset if necessary.
2. Check the continuity through the Brush Rotation
Switch to the Reverse Rotation Brush (3)
solenoid. Repair the wiring or replace the switch
as necessary.
1. Check the coil resistance of the Reverse Rotation
Brush (3) solenoid. If not 7.2 ohms ±10%, replace
the coil.
2. If the coil resistance is within spec, check for
binding or a mechanical problem. Repair or
replace the valve as necessary.
Scrub System
Scrub Brush
Solenoid (8)
Port C2 to
Top Port
on Scrub Deck
Hydraulic
Cylinder
174