Scrub System, Cylindrical 145
Service Manual – SC8000
Problem
Cause
Correction
Scrub deck
pressures will not
change; inoperative
in its three settings
The scrub deck pressures
are set incorrectly in the
User Options Menu.
Reprogram the scrub deck pressures as required.
(Refer to the
Control System/Control Board
(Driver Box) Programming Options/User Options
Menu
subsection.)
Problem in the electrical
control circuit
• Check the coil resistance on both L5 and L7
solenoids (spec. 2.2 ohms).
• Check solenoid wiring continuity from Driver Box
for both L5 and L7.
• Check the current draw on both solenoids using an
amp clamp (spec. 2.1 amps).
• Substitute a new Driver Box if the solenoid coils
and wiring check out OK, but no current is found
when activating scrub deck pressure circuit
function.
• If the electrical control circuits test OK, check for
possible Hydraulic load circuit problems.
Problem in the hydraulic
load circuit
• Inspect for binding and any possible mechanical
damage to the deck lift cylinder and deck lift
linkage.
• Remove the S5 and S7 scrub lift cylinder valve
cartridges from the manifold. Inspect, clean and
operate the cartridges outside of the manifold. If
the cartridges function OK, reinstall. If not, replace
as necessary.
• Connect a hydraulic pressure gauge at the
test ports TP4 and TP5 and check the system
operating pressures (See the table below for
specifications.)
• If the deck pressures still do not function correctly
after replacing the valve cartridge(s), replace the
scrub lift cylinder.
Test
Port
Pressure
Type
Controlled
by
Pressure
Setting
PSI
Scrub lift cylinder 1.50 x 5.00,
engine at 2200 RPM
TP4
Lift
Pressure
Proportioning
Valve S7
1
750 - 774
2
750 - 767
3
745 - 779
TP5
Down
Pressure
Proportioning
Relief Valve
S5
1
333 - 346
2
393 - 412
3
458 - 499
Pressure
Setting 1
Pressure
Setting 2
Pressure
Setting 3
Average Lift Pressure Differential
(Lift Pressure minus Down Pressure)
423 psi
353 psi
283 psi
Note:
The actual scrub pressure is determined by the differential lift pressure lifting the scrub deck
upward against the downward force of the scrub deck weight. The lower the differential lift
pressure, the higher the scrub pressure.
