Advance acoustic 56514925, Service Manual

Page: 183 / 260

Scrub System 183 Service Manual – Advance 7765 / Nilfisk CR1500
Problem Cause Correction
Scrub deck will not
extend downward
to the normal scrub
position.
No voltage to the Scrub
Brush Lock Up Solenoid
(9) in the Cylinder Control
Valve.
1. Check circuit breaker CB7 and reset if necessary.
2. Check the wiring from CB7 to the Scrub Brush
Lock Up Solenoid (9) valve and repair as
necessary.
Scrub Deck Lock Up
Solenoid (9) in the Cylinder
Control Valve not opening
when energized (stuck
closed) .
1. Check the coil resistance of the Scrub Deck Lock
Up Solenoid (9). If not 9.8 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 Brush Solenoid
(6) and/or Scrub Brush
Solenoid (8) in the Cylinder
Control Valve not moving
to the “deadhead” position
when de-energized (stuck
open).
1. Check the coil resistance of the Scrub Brush
Solenoid (6) and Scrub Brush Solenoid (8). If not
9.8 ohms ±10%, replace the coil.
2. If the coil resistances are within spec, check
for binding or a mechanical problem. Repair or
replace the valve(s) as necessary.
Scrub deck not
being lowered to
the heavy scrub
position.
No voltage to the Scrub
Brush Lock Up Solenoid
(9) in the Cylinder Control
Valve.
1. Check circuit breaker CB7 and reset if necessary.
2. Check the wiring from CB7 to the Scrub Brush
Lock Up Solenoid (9) and repair as necessary.
Scrub Deck Lock Up
Solenoid (9) in the Cylinder
Control Valve not opening
when energized (stuck
closed) .
1. Check the coil resistance of the Scrub Brush Lock
Up Solenoid (9). If the coil resistance is not 9.8
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.
No voltage to the Scrub
Brush Solenoid (8) in the
Cylinder Control Valve.
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 in the forward position.
3. Check the continuity through the Forward Relay,
Scrub Brush Switch and Brush Pressure Switch
to the Scrub Brush Solenoid (8). Repair the
wiring, or replace the relay and/or switch(es) as
necessary.
Scrub Brush Solenoid (8) in
the Cylinder Control Valve
not opening when energized
(stuck closed) .
1. Check the coil resistance of the Scrub Brush
Solenoid (8). If the coil resistance is not 9.8 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 Brush Solenoid (6)
not moving to its “deadhead”
position when de-energized
(stuck open).
1. Check the coil resistance of the Scrub Brush
Solenoid (6). If the coil resistance is not 9.8 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.