SC351

Service Manual
Advance Model Numbers: Nilfisk Model Numbers:
9087342020 SC351 9087340020 SC351
9087341020 SC351

English

11/2012 Form No. 9099876000

(D) Revised 11/2017
Service Manual – SC351 Table of Contents 2

Table of Contents
General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Machine General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Service Manual Purpose and Field of Application . . . . . . . . . . . . . . . . . . . . . . . 4
Other Reference Manuals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Service and Spare Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Serial Number Label . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Visible Symbols on the Machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
General Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Machine Lifting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Machine Transportation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Machine Nomenclature (know your machine) . . . . . . . . . . . . . . . . . . . . . . . . . 9
Control Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Service and Diagnostic Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Technical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Scheduled Maintenance Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Chassis System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Frame (main parts) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Control System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Component Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Removal and Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Electrical System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Fuses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Component Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Maintenance and Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
General Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Recovery System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Component Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Component Locations (Continues) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Maintenance and Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Removal and Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Service Manual – SC351 Table of Contents 3

Scrub System, Disc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Component Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Maintenance and Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Removal and Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Solution System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Component Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Removal and Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Squeegee System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Component Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Maintenance and Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Wheel System, Non-Traction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Component Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Service Manual – SC351 General Information 4

General Information

Machine General Description

The SC351 is a “walk behind” industrial machine designed to wash and dry floors in one pass. The machine is
powered by on-board batteries. The machine is equipped with disc brushes, a controlled solution flow dosing
system and a squeegee with blades integrated in the deck, which vacuums and dries the floor.

Service Manual Purpose and Field of Application

The Service Manual is a technical resource intended to help service technicians when carrying out mainte-
nance and repairs on the SC351, to guarantee the best cleaning performance and a long working life for the
machine.
Please read this manual carefully before performing any maintenance and repair procedure on the machine.

Other Reference Manuals

Model Product Code User Manual Spare Parts List
Advance SC351 9087342020 9099867000 9099868000
Nilfisk SC351 9087340020
9099864000 9099865000
Nilfisk SC351 9087341020

These manuals are available at:

• Local Advance or Nilfisk retailer
• Advance website: www.advance-us.com
• Nilfisk website: www.nilfisk.com
Service Manual – SC351 General Information 5

Conventions
Forward, backward, front, rear, left or right are intended with reference to the operator’s position, that is to
say in driving position.

Service and Spare Parts

Service and repairs must be performed only by authorised personnel or Advance/Nilfisk Service Centers. The
authorised personnel is trained directly at the manufacturer’s premises and has original spare parts and ac-
cessories.
Contact Advance or Nilfisk Retailer indicated below for service or to order spare parts and accessories, specify-
ing the machine model and serial number.

(Apply Retailer label here)

Serial Number Label

The machine serial number and model name are
marked on the plate (see the example to the side).
Product code and year of production are marked on
the same plate.
This information is useful when requiring machine
spare parts. Use the following table to write down
the machine identification data.

Model: Scrubber-Dryer SC351 Serial No: ..................

Prod. Nr: 9087342020 Date code: .......
GVW: 80 kg/176 lb IPX4 LpA = 64 dB(A)
42 A Charg.100-240Vac 50/60Hz Battery 12 Vdc
Type E Floor cleaning machine
Control Nr:
UL STD 583 3084826
2%
CSA STD C22.2 N.68-92

“Made in Hungary”
Nilfisk-Advance, Inc.
Plymouth, MN, USA
A Nilfisk-Advance Brand www.advance-us.com

P100771

MACHINE model ..............................................................................................

PRODUCT number ...........................................................................................

MACHINE serial number ..................................................................................

Service Manual – SC351 General Information 6

Safety
The following symbols indicate potentially dangerous situations. Always read this information carefully and
take all necessary precautions to safeguard people and property.

Visible Symbols on the Machine

WARNING!
Carefully read all the instructions before performing any operation on the machine.

WARNING!
Do not wash the machine with direct or pressurized water jets.

WARNING!
max.2
% Do not use the machine on slopes with a gradient exceeding the specifications.

Symbols
Danger! It indicates a dangerous situation with risk of death for the operator.

Warning! It indicates a potential risk of injury for people or damage to objects.

Caution! It indicates a caution related to important or useful functions.

Note: It indicates a remark related to important or useful functions.

General Instructions
Specific warnings and cautions to inform about potential damages to people and machine are shown below.

Warning! Make sure to follow the safety precautions to avoid situations that may lead to
serious injuries.

−− Before performing any cleaning, maintenance, repair or replacement procedure, turn the func-
tion selection knob to “0” and disconnect the battery connector.
−− This machine must be used by properly trained operators only.
−− Do not wear jewels when working near electrical components.
−− Do not work under the lifted machine without supporting it with safety stands.
−− Do not operate the machine near toxic, dangerous, flammable and/or explosive powders, liquids
or vapours: This machine is not suitable for collecting dangerous powders.
−− Keep the battery away from sparks, flames and incandescent material. During the normal opera-
tion explosive gases are released.
−− Battery charging produces highly explosive hydrogen gas. Keep the cover open during battery
charging and perform this procedure in well-ventilated areas and away from naked flames.
Service Manual – SC351 General Information 7

Caution! Make sure to follow the safety precautions to avoid situations that may lead to
serious injuries, damages to materials or equipments.

−− Carefully read all the instructions before performing any maintenance/repair procedure.
−− Before using the battery charger, ensure that frequency and voltage values, indicated on the
machine serial number plate, match the electrical mains voltage.
−− Do not pull or carry the machine by the battery charger cable and never use the battery charger
cable as a handle. Do not close a door on the battery charger cable, or pull the battery charger
cable around sharp edges or corners. Do not run the machine on the battery charger cable.
−− Keep the battery charger cable away from heated surfaces.
−− Do not use the machine if the battery charger cable or plug is damaged. If the machine is not
working as it should, has been damaged, left outdoors or dropped into water, return it to the
Service Center.
−− To reduce the risk of fire, electric shock, or injury, do not leave the machine unattended when
it is plugged in. Before performing any maintenance procedure, disconnect the battery charger
cable from the electrical mains.
−− Do not smoke while charging the battery.
−− Always protect the machine against the sun, rain and bad weather, both under operation and
inactivity condition. Store the machine indoors, in a dry place: This machine must be used in dry
conditions, it must not be used or kept outdoors in wet conditions.
−− Before using the machine, close all doors and/or covers as shown in the User Manual.
−− This machine is not intended for use by persons (including children) with reduced physical,
sensory or mental capabilities, or lack of experience and knowledge, unless they have been given
supervision or instruction concerning use of the machine by a person responsible for their safety.
−− Children should be supervised to ensure that they do not play with the machine.
−− Close attention is necessary when used near children.
−− Use only as shown in this Manual. Use only Advance or Nilfisk’s recommended accessories.
−− Check the machine carefully before each use, always check that all the components have been as-
sembled before use. If the machine is not perfectly assembled it can cause damages to people and
properties.
−− Take all necessary precautions to prevent hair, jewels and loose clothes from being caught by the
machine moving parts.
−− Pay attention to the machine moving parts. When using the machine, the deck can abruptly turn
by 180°.
−− Do not use the machine on an incline.
−− Do not tilt the machine more than the angle indicated on the machine itself, in order to prevent
instability.
−− Do not use the machine in particularly dusty areas.
−− Use the machine only where a proper lighting is provided.
−− While using this machine, take care not to cause damage to people or objects.
−− Do not bump into shelves or scaffoldings, especially where there is a risk of falling objects.
−− Do not lean liquid containers on the machine, use the relevant can holder.
−− The machine operating temperature must be between +32°F and 104°F (0°C and +40°C).
−− The machine storage temperature must be between +32°F and 104°F (0°C and +40°C).
−− The humidity must be between 30% and 95%.
Service Manual – SC351 General Information 8

−− When using floor cleaning detergents, follow the instructions on the labels of the detergent bot-
tles.
−− To handle floor cleaning detergents, wear suitable gloves and protections.
−− Do not use the machine as a means of transport.
−− Do not allow the brush to operate while the machine is stationary to avoid damaging the floor.
−− In case of fire, use a powder fire extinguisher, not a water one.
−− Do not tamper with the machine safety guards and follow the ordinary maintenance instructions
scrupulously.
−− Do not allow any object to enter into the openings. Do not use the machine if the openings are
clogged. Always keep the openings free from dust, hairs and any other foreign material which
could reduce the air flow.
−− Do not remove or modify the plates affixed to the machine.
−− This machine cannot be used on roads or public streets.
−− Pay attention during machine transportation when temperature is below freezing point. The
water in the recovery tank or in the hoses could freeze and seriously damage the machine.
−− Use brushes and pads supplied with the machine or those specified in the User Manual. Using
other brushes or pads could reduce safety.
−− In case of machine malfunctions, ensure that these are not due to lack of maintenance. If neces-
sary, request assistance from the authorised personnel or from an authorised Service Center.
−− If parts must be replaced, require ORIGINAL spare parts from an Authorised Dealer or Retailer.
−− To ensure machine proper and safe operation, the scheduled maintenance shown in the relevant
chapter of this Manual, must be performed by the authorised personnel or by an authorised Ser-
vice Center.
−− Do not wash the machine with direct or pressurised water jets, or with corrosive substances.
−− The machine must be disposed of properly, because of the presence of toxic-harmful materials
(battery, etc.), which are subject to standards that require disposal in special centres (see Scrap-
ping chapter).

Machine Lifting
Warning! Do not work under the lifted machine without supporting it with safety stands.

Machine Transportation
Warning! Before transporting the machine, make sure that:

All covers are closed.

The battery is disconnected.

The machine is securely fastened to the means of transport.

 Service Manual – SC351 General Information 9

Machine Nomenclature (know your machine)

Transparent cover with vacuum grid
Handlebar with
control panel
Vacuum grid with
automatic shut-off float
Recovery tank
Battery
Battery charger connection
cable holder connector

Fuses Deck bumper

wheels Can holder

Battery charger
cable

Serial number plate/

technical data/
Squeegee Accessory and battery
conformity certification
Squeegee blades compartment cover (closed)
Cover latch assembly
Solution tank filler plug
Accessory and battery GEL/AGM
compartment cover battery Vacuum system
(open) Battery charger motor

Rear wheels
Brush/pad-holder deck on fixed axle

Squeegee vacuum hose Solution tank

Brush deck gearmotor

Brush rotation direction

Brush deck wheels
P100772
Service Manual – SC351 General Information 10

Control Panel
Program selection knob/rotary switch
Scrubbing program: Scrubbing and drying program: Brush activation
brush - solution flow activation - Vacuum system activation
- Solution flow activation
Drying program:
brush - vacuum system activation Machine switching off “0”
Handlebar inclination adjusting lever

Brush levers Machine start-up Brush levers

enabling push-button
Battery charge LED indicators Solution flow switch
P100773
Service Manual – SC351 General Information 11

Service and Diagnostic Equipment

Besides a complete set of standard meters, the following instruments are necessary to perform fast checks and
repairs on Nilfisk-Advance machines:
• Laptop computer charged with the current version of EzParts, Adobe Reader and (if possible) Internet
connection
• Digital Volt Meter (DVM)
• Amp clamp with possibility of making DC measurements
• Hydrometer
• Battery charge tester to check 12 V batteries
• Static control wrist strap
• Dynamometric wrench set
• A copy of the User Manual and Spare Parts List of the machine to be serviced (provided with the machine
or available at www.advance-us.com or other Nilfisk-Advance websites).

The following equipment is also available at Nilfisk-Advance Centers:

• Vacuum water lift gauge, P/N 56205281
Service Manual – SC351 General Information 12

Technical Data
Advance Nilfisk Nilfisk
Description
SC351 SC351 SC351 full PKG
Solution tank capacity 2.9 USgal (11 litres)
Recovery tank capacity 2.9 USgal (11 litres)
Min/max machine length at the handlebar 30.3 / 48 in (770 / 1 220 mm)
Machine width 18.7 in (475 mm)
Min/max machine height with adjustable handlebar 21.6 / 42.7 in (550 / 1 085 mm)
Body machine dimension 28.6 x 17 x 17.5 in (726 x 432 x 446 mm)
Minimum turning radius 21.6 in (550 mm)
Cleaning width 14.5 in (370 mm)
Diameter of wheels on fixed axle 8.4 in (214 mm)
Wheel pressure on the floor (*) 72.5 psi (0.5 N/mm2)
Brush/pad diameter 14.5 in (370 mm)
Brush/pad pressure on the floor 39.6 lb (18 Kg)
Brush/pad pressure with full tank 59.5 lb (27 Kg)
One drop: 0.066 gpm (0.25 litres/min)
Min/max solution flow
Two drops: 0.13 gpm (0.5 litres/min)
Sound pressure level at workstation
64 dB(A) ± 3 dB(A)
(ISO 11201, ISO 4871, EN 60335-2-72) (LpA)
Machine sound pressure level
84 dB(A)
(ISO 3744, ISO 4871, EN 60335-2-72) (LwA)
Vibration level at the operator’s arms (ISO 5349-1, EN 60335-2-72) 98.4 in/s2 (< 2.5 m/s2)
Maximum gradient when working 2%
IP protection class X4
Protection class (electric) III
Vacuum system motor power 0.27 hp (200 W)
Max vacuuming (with closed inlet) 27.7 in/H2O (710 mmH2O)
Brush motor power 0.35 hp (260 W)
Brush motor speed 140 rpm
Total absorbed power 42 A (0.5 kW)
Battery compartment size 17.8 x 6.9 x 9.4 in (350 x 175 x 240 mm)
Battery voltage 12 V
12 V 55 AhC20 AGM
Standard battery 12 V 84 AhC5 AGM -
spiralcell
100-240 VAC - Ouput 12 Vdc - 12 A (SPE)
Battery charger
- 230 VAC - Ouput 12 Vdc - 15 A (Micropower)
Work autonomy (standard battery) 2 hour 1 hour
Weight without battery and with empty tanks 92.6 lb (42 Kg) 97.0 lb (44 Kg) 97.0 lb (44 Kg)
Gross vehicle weight (GVW) 176 lb (80 Kg)
Shipping weight 171.9 lb (78 Kg) 105.8 lb (48 Kg) 154.3 lb (70 Kg)

(*) Machines have been tested under the following conditions:

◦◦ Battery maximum size
◦◦ Maximum brush and squeegee size
◦◦ Full clean water tank
◦◦ Optional equipment installed
◦◦ Wheel weight checked
◦◦ Print on the floor checked on cement for each single wheel
◦◦ Result expressed as maximum value for both front and rear wheels
 Service Manual – SC351 General Information 13

Dimensions
42.7 in - 1 085 mm
21.6 in - 550 mm

17.5 in - 446 mm

30.3 in - 770 mm 17 in - 432 mm

48 in - 1 220 mm 18.7 in - 475 mm

28.6 in - 726 mm
P100774
Service Manual – SC351 General Information 14

Maintenance
The lifespan of the machine and its maximum operating safety are ensured by correct and regular mainte-
nance.

Warning! Read carefully the instructions in the Safety chapter before performing any
maintenance procedure.

The following tables provides the scheduled maintenance. The intervals shown may vary according to particu-
lar working conditions, which are to be defined by the person in charge of the maintenance.
For instructions on maintenance procedures, see the following paragraphs.

Scheduled Maintenance Table

Daily, after using the Every six
Procedure Weekly Yearly
machine months

Battery charging

Squeegee Cleaning

Brush Cleaning

Tank and Vacuum Grid Cleaning

Squeegee blade check and/or replacement

Solution valve check and cleaning

Brush deck rotation clutch check and/or replacement

Service Manual – SC351 Chassis System 15

Chassis System

Frame (main parts)

1. Frame

2. Handlebar holder

3. Wheels on fixed axle

P100775
Service Manual – SC351 Control System 16

Control System

Functional Description
The function control is performed with the program The LED electronic board (EB1) is equipped with 3
selection knob/rotary switch (SW1), the machine LEDs which indicate the battery charge level, both
start-up enabling push-button (SW2) (which must be during operation and while recharging:
used simultaneously with the brush levers) and the
Battery charge level
solution flow switch (SW3). LED display
The switch outputs controls the relevant outputs: re-
lay (K1) for brush motor, relay (K2) for vacuum sys-
tem motor, solenoid valve (EV).
The control circuit are protected by the fuse (F3).
The negative output of the battery charger (B2) al-
lows function activation when battery level is suffi-
cient and the battery charger is not connected to the
electrical mains.

Diagram of Output Activation according to the Position of the Switches (SW1), (SW2)
and (SW3)
Program selection knob/ Machine start-up Brush motor (M1) Solenoid valve (EV) Vacuum system motor
rotary switch (SW1) enabling push-button (M2)
settings (SW2) settings (with
brush activation levers)

O Pressed/released Off Off Off

Released Off Off On

Pressed On On On
Released Off Off Off
Pressed On On Off
Released/ Off Off On
Pressed On Off On

Solution flow push-button setting (SW3) Symbols Solenoid valve ON time Solenoid valve OFF time
(EV) (EV)

0 2 sec 2 sec

1 Always ON -
Service Manual – SC351 Control System 17

Component Locations
• Handlebar with control panel • Machine start-up enabling push-button (SW2)
• Program selection knob/rotary switch (SW1) • Solution flow switch (SW3)
• LED electronic board (EB1) • Wiring harness
• Brush levers • Handlebar inclination adjusting lever

Machine start-up
enabling push-button
(SW2)

Solution flow switch

(SW3)

Handlebar with control

panel

Brush levers

Handlebar inclination
and height adjusting
lever

Program selection
knob/rotary switch
(SW1)

Wiring harness

LED electronic board

(EB1)

P100777
Service Manual – SC351 Control System 18

Removal and Installation

LED Electronic Board (EB1) Disassembly/Assembly

Disassembly 6. Disconnect the connector (C) of the LED
electronic board (D). Remove the screws (E) and
1. Drive the machine on a level floor. Make sure remove the LED electronic board (D).
that the machine cannot move independently.
7. If necessary, disconnect the connector (F) and
2. Turn the machine program selection knob to “0”. remove the solution flow push-button (G) by
3. Disconnect the battery connector. disengaging the inner tabs (H).

4. On the lower side of the handlebar with the

control panel, unscrew the screws (A).

5. Lower the upper side (B) of the handlebar with

the control panel.

A A

A A

C
F

E
D
G H E

P100778
Service Manual – SC351 Control System 19

LED Electronic Board (EB1) Disassembly/Assembly (Continues)

8. If necessary, remove the selector assembly (N) of the machine program selection knob (I), as shown
below:
• Disconnect the connectors (J)
• On the outer side, turn the knob (I) on the position (K) (vacuum system activation).
• Loosen the threaded dowel inside the housing (L), then remove the knob (I) from the housing.
• Remove the screws (M) and, from the inside, remove the selector assembly (N) of the knob (I).

Assembly

9. Assemble the components in the reverse order of disassembly.

L
M
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Service Manual – SC351 Control System 20

Machine Enabling Push-Button Disassembly/Assembly (SW2)

Disassembly

1. Drive the machine on a level floor. Make sure that the machine cannot move independently.

2. Turn the machine program selection knob to “0”.

3. Disconnect the battery connector (red).

4. On the lower side of the handlebar with the control panel, unscrew the screws (A).

5. Move the upper side (B) of the handlebar with the control panel.

6. Remove the screws (C) and move the lower side (D) of the handlebar from the frame (E).

7. Disconnect the connectors (F) of the brush enabling push-button (G).

8. Remove the screws (H) and remove the switch (G).

9. If necessary, remove from the housing the enabling push-button (I) of the switch (G).

10. If necessary, remove the brush levers (J) from the housing.

Assembly

11. Assemble the components in the reverse order of disassembly.

A A

A A

C C
I H

J F F

D G

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Service Manual – SC351 Control System 21

Specifications

LED electronic board connector (EB1)

JA: 4-way vertical Tyco Modu II type

1 2 3 4

PIN Description Electronic board V ref. I max.

in/out

1 Common cathode LED power supply in 0V <1 A

2 RED anode LED power supply in 0.7 V <1 A

3 YELLOW anode LED power supply in 0.7 V <1 A

4 GREEN anode LED power supply in 0.7 V <1 A

Service Manual – SC351 Electrical System 22

Electrical System

Functional Description
The program selection knob/rotary switch (SW1) and the machine start-up enabling push-button (SW2) con-
trols the vacuum brush motor relay (K1) for the activation of the brush motor (M1) and the vacuum system
motor relay (K2) for the activation of the vacuum system motor (M2).
The solenoid valve (EV) is controlled by the solenoid valve timer relay (KT1) when the solution flow switch
(SW3) is turned to 0 (minimum flow); the timer is bypassed when the solution flow switch (SW3) is turned to
1 (maximum flow).
The battery charger (CH) supplies negative power to all the control relays only when the battery charge is suf-
ficient and the battery charger is not connected to the electrical mains.
The machine system is connected to the battery with the connector (C1).

Fuses
The brush motor (M1) is protected by the brush motor fuse (F1). The vacuum system motor (M2) is protected
by the vacuum system motor fuse (F2). The solenoid valve (EV) is protected by the function selector fuse (F3).
The battery charger (CH) has inner safety protections which are not accessible.

Wiring Diagram
LED
ELECTRONIC BOARD (EB1) BATTERY CHARGER (CH)
R
Y
G

12 V BATTERY (BAT)

CONNECTOR (C1) CONNECTOR (C1)

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 Service Manual – SC351 Electrical System 23

Component Locations
• Battery charger (CH) • Vacuum system motor fuse (F2)
• 12V Battery (BAT) • Function selector fuse (F3)
• Connector (C1) • Brush motor relay (K1)
• Battery wiring harness • Solenoid valve timer relay (KT1)
• Machine wiring harness • Vacuum system motor relay (K2)
• Brush motor fuse (F1)

12V Battery (BAT)

Battery charger (CH)

Function selector fuse

(F3)
Battery wiring harness

Vacuum system motor

Connector (C1)
fuse (F2)

Machine wiring
Brush motor fuse (F1) harness

Solenoid valve timer

relay (KT1)
Brush motor relay (K1)

Vacuum system motor

relay (K2)

P100782
Service Manual – SC351 Electrical System 24

Maintenance and Adjustments

Battery Installation
1. Open the cover and check that the battery connector is disconnected.

2. Install the battery on the machine, connect the terminals and fasten it with the relevant belt.

Warning! This machine requires sealed lead batteries (GEL or AGM technology). Do not use
batteries with liquid electrolyte or not sealed (WET) for any reason.

Warning! Pay special attention when connecting the battery pins. The red cable must be
connected to the positive pin (+), the black cable must be connected to the negative
pin (-) of the battery. A wrong connection can damage the battery charger.

Warning! The installed battery (GEL/AGM) may require a specific charging algorithm: See the
Battery Charger Setting and Dipswitch Configuration paragraph to set the proper
charging algorithm for the installed battery.

3. Connect the battery connector and close the cover.

4. Charge the battery.

Battery charging

Note: Charge the battery when the yellow or red LED turns on, or at the end of each working
cycle. Keeping the battery charged make their life last longer.

Caution! When the battery is discharged, charge is as soon as possible, as that condition
makes its life shorter. Check for battery charge at least once a week.

1. Drive the machine on a level floor.

2. Check that the function selection knob is turned to “0”.

3. Connect the battery charger cable to the electrical mains (the electrical mains voltage and frequency
must be compatible with the battery charger values shown on the machine serial number plate).

Note: When the battery charger is connected to the electrical mains, all machine functions
are automatically cut off. The red or yellow warning light (37) is on when the battery
charger is charging the battery.

4. When the green warning LED stays on, the battery charging cycle is over.

5. When the battery charging is completed, disconnect the battery charger cable from the electrical mains
and wind it round its housing.

6. Now the machine is ready to be used.

Note: For further information about the operation of the battery charger, see the relevant
Manual attached.
Service Manual – SC351 Electrical System 25

Battery Charger Setting and Dipswitch Configuration (SPE version)

To change the dipswitch configuration, remove the round white cap near the openings (see the illustration
below), with a screwdriver.

CBHD2 12V 12A IUIa OPTIMA DIPSWITCH CONFIGURATION

P100782

SW1
DP1 DP2
ON ON ON

RED YELLOW GREEN

LED LED LED OFF OFF

P100783
SW1 LED CODE(*) CHARGING CURVE
SW1 LED CODES
DP1 (*)DP2 Battery LEDs CHARGING CURVES

DP1 DP2 BATTERYON CHARGING

ON LEDS
2 flashes (on the control
of GREEN IUU0-GEL for generic Gel and AGM batteries
panel) 2 flashes of
ON OFF IUIa-AGM for DISCOVER AGM batteries
RED&GREEN
ON ON 2 flashes of the GREEN LED Charging algorithm for generic Gel and AGM battery
2 flashes of IUIa-OPTIMA for OPTIMA batteries
OFF ON
YELLOW&GREEN (default)
ON OFF 2 flashes of the RED and GREEN LEDS Charging algorithm for AGM DISCOVER battery
OFF OFF 2 flashes of YELLOW (default
IUIa-GEL for Advance
for EXIDE model)
SONNENSCHEIN Gel
batteries

OFF ON 2 flashes of the

(*) the LED YELLOW
code and
is shown by theGREEN LEDS
battery status Charging
LEDs every algorithm
time the charger isfor OPTIMA
powered on, battery
before to start the charging cycle.
(default for Nilfisk model)

OFF OFF 2 flashes of the YELLOW LED Charging algorithm for EXIDE SONNENSCHEIN Gel battery
To change the dipswitch configuration, please remove the round black
(*) The LED codes arecapshown
locatedbyclose
the battery chargeonindicators
to the openings the bottomeach
of thetime that(see
charger thethe
battery charger is turned
picture below), using a tool like a screwdriver.
on, before the charging cycle starts.
dipswitch
Service Manual – SC351 Electrical System 26

Battery Charger Setting (MICROPOWER version)

To change the configuration push repeatedly the button for changing charging curve with a screwdriver.

Button for changing charging curve

BATTERY CHARGING LEDS (on the control CHARGING CURVES

panel) (*)

2 flashes of the YELLOW and GREEN LEDS Charging algorithm for OPTIMA battery (default for Nilfisk model)

2 flashes of the RED and GREEN LEDS Charging algorithm for AGM DISCOVER battery

2 flashes of the GREEN LED Charging algorithm for generic Gel and AGM battery

2 flashes of the YELLOW LED Charging algorithm for EXIDE SONNENSCHEIN Gel battery

(*) The LED codes are shown by the battery charge indicators each time that the battery charger is turned
on, before the charging cycle starts.

LED codes on the battery charger

RED LED YELLOW LED

LED CODES (on the battery charger) ERROR

Flashes of the RED LED Low or high battery voltage or no battery connected

Flashes of the YELLOW LED and on steady of the RED LED Maximum recharge time expired

On steady of the YELLOW and RED LEDS Faulty connected battery polarity
Service Manual – SC351 Electrical System 27

Battery Charger Auxiliary Functions

The battery charger is also used to:

7. Check the battery voltage during machine operation.

8. Display the battery charge level with the led electronic board (EB1).

9. Stop the machine operation when the battery is discharged (10.8 V).

10. Disable the machine operation during battery recharging.

For this reason, the following battery charger auxiliary contacts are used:
• B1: (ref. + 12 V) Enabling input for machine start-up.
• B2: (ref. 0 V) Output for machine function activation.

Fuse Check and Replacement

Fuses in the electric component box

1. Drive the machine on a level floor.

2. Check that the function selection knob is turned to “0” and disconnect the battery connector.

3. Open the cover and check one of the following fuses for deactivation or integrity:
◦◦ (A): brush motor fuse circuit breaker (F1) 35 A.
◦◦ (B): vacuum system motor blade fuse (F2) 30 A.
◦◦ (C): function selector blade fuse (F3) 5 A.

4. Reset or replace any fuse, after having checked and repaired any problem that caused deactivation.

5. Close the cover.

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Service Manual – SC351 Electrical System 28

Deep discharged battery (only for Optima battery type 4.2 - Spiralcell)

The discharge of the battery through normal use of the machine is stopped when the voltage reaches 10,8V (see
the Battery Charger Auxiliary Functions paragraph).
However, if the battery is left in these conditions for a long period of time, or in case of failure of the battery, the
voltage (*) may fall below this value.
If the open circuit voltage of the battery falls below the value of 10.5V, then it can no longer be recharged by the
charger on board.
The battery charger indicates this error when connecting to the network by turning on all 3 LED lights steadily,
and does not start the charging cycle.
In this case the battery is considered deep discharged permanent and cannot in any case fully recover its functio-
nality and durability.
The best solution is therefore to replace it.

If attempt to recover the capacity, even partially, a standalone charger must be used.

To perform the recovery recharge, remove the battery from the machine and connect it to a suitable charger with
the following characteristics:

• Battery-charger electronic
• Charging curve for generic batteries GEL / AGM or specific OPTIMA batteries
• Rated output voltage : 12V
• Rated output current : 5 to 10 Amperes

Danger! Perform the recovery charge exclusively with battery removed from the machine and
under the constant supervision of qualified personnel, in a well-ventilated area.

Danger! The battery may indeed have suffered substantial damage and overheat during this
charging. Never leave the battery unattended to be charged in these circumstances.

Danger! In case of abnormal heating during recovery charge of the battery [surface
temperature >122° F (>50°C)] or the smoke or smell, immediately stop charging the
battery and scrap it.

Once the recovery recharge completed it’s possible to re-install the battery on the machine and test its functionali-
ty.

(*) For no-load voltage of the battery means voltage measured with a multimeter when the battery is disconnected from any
load for at least a few minutes.
Service Manual – SC351 Electrical System 29

Troubleshooting
Trouble Possible Causes Remedy

The machine is not working; no The battery connector (C1) is not connected or Connect or replace it
LED turns on. broken

The 12V battery (BAT) is completely discharged Try to the battery functionality recover or replace it
(see the Deep discharged battery paragraph)

The 12V battery (BAT) is broken Check the battery no-load voltage

The battery charger (CH) is broken Replace

The function selector fuse (F3) is open Replace

The wiring harness is cut or pressed or short Repair

circuited

The program selection knob/rotary switch (SW1) Replace

is not working

The battery has been connected with inverted Replace the battery charger
polarity

By connecting the battery charger

to the power supply all 3 LEDs
12V battery (BAT) damaged or heavy Try to the battery functionality recover or replace it
on the handlebar are on with a
discharged (see the Deep discharged battery paragraph)
steady light and it is not charging
the battery.

By connecting the battery charger

to the power supply
12V battery (BAT) not correctly connected to the
the yellow LED on the handlebar Verify the battery connections
wiring system
is flashing and it is not charging
the battery

By connecting the battery charger

to the power supply
the red LED on the handlebar is Internal battery charger damage Replace
flashing and it is not charging the
battery

At the end of the battery charging The battery charger was not able to charge
Try to repeate the charging.
phase the red LED on the completely the battery within the maximum time
If the problem still occurs replace the battery
handlebar is flashing allowed
 Service Manual – SC351 Electrical System 30

General Wiring Diagram

BRUSH MOTOR FUSE (F1)

VACUUM SYSTEM FUNCTION SELECTOR FUSE (F3)

MOTOR FUSE (F2)

PROGRAM SELECTION CONNECTOR (C1)

KNOB/ROTARY SWITCH (SW1)
BATTERY CHARGER (CH)
VACUUM SYSTEM
MOTOR RELAY (K2)

MACHINE START-UP DIODE (D2)

ENABLING
PUSH-BUTTON (SW2)

VACUUM SYSTEM DIODE (D1)

MOTOR (M2)

SOLENOID VALVE
TIMER RELAY (KT1) R Y G

BRUSH SOLUTION FLOW

MOTOR (M1) SWITCH (SW3)
LED ELECTRONIC
BOARD (EB1)

M1 M2 12 V BATTERY (BAT)
BRUSH MOTOR
RELAY (K1)

VACUUM SYSTEM
MOTOR RELAY (K2)
CONNECTOR (C1)

SOLENOID VALVE (EV)

BRUSH MOTOR
RELAY (K1)

P100785
Service Manual – SC351 Electrical System 31

Specifications
Advance Nilfisk Nilfisk
Description
SC351 SC351 SC351 full PKG

Total absorbed power 42 A (0.5 kW)

Battery compartment size 17.8x6.9x9.4 in (350x175x240 mm)

Battery voltage 12 V

12 V 55 AhC20 AGM
Standard battery 12 V 85 AhC5 AGM -
spiralcell

100-240 VAC - Ouput 12 Vdc - 12 A (SPE)

Battery charger
- 230 VAC - Ouput 12 Vdc - 15 A (Micropower)

Work autonomy (standard battery) 2 hour 1 hour

Service Manual – SC351 Recovery System 32

Recovery System

Functional Description
The water recovery system removes the dirty water from the floor and pipes it to a recovery tank. When the
machine is running, the dirty water on the floor is collected by the squeegee blades and collected through the
slots in the same, piped through the vacuum hose and into the tank by the airflow created by vacuum motor
(M2). The dirty water is piped into the recovery tank, while the airflow continues to the vacuum fan.
The vacuum system motor (M2) is supplied by the vacuum system motor relay (K2) which is driven by the
program selection knob/rotary switch (SW1) when it is turned to 1 or 3. The circuit is protected by the vacuum
system motor fuse (F2).
The automatic float in the vacuum grid stops vacuum system motor (M2) from collecting any liquids.
When the automatic float closes and shuts down the vacuum system, the vacuum system motor noise will in-
crease and the floor will not be dried.
When the recovery tank is full it must be emptied.

Wiring Diagram

VACUUM SYSTEM FUNCTION

MOTOR FUSE (F2) SELECTOR FUSE (F3)

PROGRAM SELECTION
KNOB/ROTARY SWITCH (SW1)
BATTERY CHARGER (CH)

VACUUM SYSTEM
MOTOR RELAY (K2)

VACUUM SYSTEM
MOTOR RELAY (K2)
VACUUM SYSTEM
M2 MOTOR (M2)

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Service Manual – SC351 Recovery System 33

Component Locations
• Recovery tank • Squeegee vacuum hose
• Vacuum system/tank connection gasket • Vacuum system motor (M2)

Recovery tank

Squeegee vacuum
hose

Vacuum system/tank
connection gasket

Vacuum system motor

(M2)

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Service Manual – SC351 Recovery System 34

Component Locations (Continues)

• Transparent cover • Vacuum system motor fuse (F2)
• Vacuum grid with automatic shut-off float • Vacuum system relay (K2)
• Cover gasket

Vacuum grid with

automatic shut-off
float

Cover gasket

Transparent cover

Vacuum system motor

fuse (F2)

Vacuum system relay

(K2)

P100788
Service Manual – SC351 Recovery System 35

Maintenance and Adjustments

Tank and Vacuum Grid Cleaning

1. Drive the machine to the appointed disposal
area. J
A
2. Check that the function selection knob is turned
to “0” and disconnect the battery connector. K

3. Remove the cover (A), clean and wash the cover

and the vacuum grid (B) with clean water.

4. Drain the water from the tanks (C and D) and

clean them.
G
5. If necessary, disassemble the grid (B) and E
remove the float (E), than clean with care and F
reinstall. H D
6. Check the recovery tank cover gasket (F) for C
integrity.
B
Note: The gasket (F) creates
vacuum in the tank that is
necessary for vacuuming the
recovery water.
I
7. If necessary replace the gasket (F) by removing
it from its housing (G) on the cover. When I
assembling the new gasket, install the joint (H)
in the area shown in the figure.

8. Check that the seating surface (I) of the gasket

(F) is clean and adequate for the gasket itself.

9. Check the vacuum duct (J) and the gasket (K),

carefully clean if necessary.

10. Reinstall the recovery tank cover (A).

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Service Manual – SC351 Recovery System 36

Vacuum System Gasket Cleaning

Note: The gaskets (L) and (M)
create vacuum in the A
system that is necessary
for vacuuming the recovery
water.
1. Drive the machine on a level floor.

2. Check that the function selection knob is turned

to “0” and disconnect the battery connector.

3. Open the cover (A) and check the vacuum

system motor gasket (L) for integrity. L
4. If necessary replace the gasket by removing it C
from its housing.

5. Remove the recovery tank (C).

6. Check the recovery water duct gasket (M) for

integrity. If necessary, replace the gasket.

7. Clean with care and reinstall.

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Service Manual – SC351 Recovery System 37

Troubleshooting
Trouble Possible Causes Remedy
The vacuum system motor (M2) does not The program selection knob/rotary switch (SW1) is Replace.
turn on. broken.
The vacuum system motor (M2) is faulty. Check the amperage.

Replace.

The vacuum system motor fuse (F2) is open. Replace.

The vacuum system motor relay (K2) is broken. Replace.

The recovery water vacuuming is The vacuum grid with automatic shut-off float is activated Drain the recovery tank.
insufficient or there is no vacuuming. because the recovery tank is full.
The vacuum grid is dirty. Clean.

The transparent cover is not properly positioned. Adjust.

The tank cover gasket is not sealing. Clean/replace.

The vacuum system motor filter is dirty. Clean.

The vacuum gaskets are damaged or do not match Repair or replace.

perfectly.
The squeegee or the vacuum hose is clogged or Clean/repair/replace.
damaged.
Service Manual – SC351 Recovery System 38

Measure the vacuum suction at the end of the recovery hose with a gauge pressure

Warning! This procedure must be performed by qualified personnel only.

Note: For the particular shape of the end vacuum hose (not circular), this operation is to be
performed with a suitable rettangular support mounted on the gauge.

1. For this measurement, full charge the battery. With the machine off, the battery voltage must be
≥ 12.6V.

2. Disconnect the vacuum hose from the squeegee.

3. Turn the knob on the number 3 working program and leave turned on the vacuum motor for 1 minute.

4. Place the gauge pressure on the suction hose and wait 30 seconds approximately to his stabilize.

5. The vacuum suction value must be ≥ 22.8 inH2O (580 mmH2O).

P100791
Service Manual – SC351 Recovery System 39

Vacuum System Motor Amperage Check

1. Remove the solution and recovery water tanks.

2. Apply the amp clamp (A) on the cable (B).

3. Turn the knob on the working program.

4. Check that the motor amperage is between 15 and 18 A at 12 V.

5. Turn the knob to “0”.

6. Remove the amp clamp (B).

7. If the amperage is higher than specified, disassemble the vacuum system motor (see the procedure in
the relevant paragraph), and check the condition of its moving parts.

8. If the procedure does not lead to a correct amperage, it is necessary to replace the motor.

9. Reinstall the solution and recovery water tanks.

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Service Manual – SC351 Recovery System 40

Removal and Installation

Vacuum System Motor Disassembly/Assembly

Disassembly 7. Remove the motor (B) and the acoustic
insulation pipe (G)
1. Remove the solution and recovery water tanks.
8. Check the gasket (F) and the gasket (H) for
2. Make sure that the battery connector is damage. If necessary, replace.
disconnected.

3. Disconnect the 2 electrical connectors (A) for the Assembly

motor (B).
9. Assemble the components in the reverse order of
4. Remove the acoustic insulation panel (C). disassembly and note the following:
◦◦ When installing the gasket (I) into the hous-
5. Remove the screws (D), recover the washers and ing (J) turn it until the lower tooth (K) and
nuts. upper teeth (L) are as shown in the figure.
◦◦ Install the motor (B) with the power supply
6. Remove the motor cover (E) and recover the contacts as shown in the figure (M).
gasket (F).

H
L
D
K I D

E
J

L F
B

I
B

G
M

P100792
Service Manual – SC351 Recovery System 41

Specifications
Advance Nilfisk Nilfisk
Description
SC351 SC351 SC351 full PKG
Recovery tank capacity 2.9 USgal (11 litres)

Vacuum system motor power 0.27 hp (200 W)

Max vacuuming (with closed inlet) 27.7 in/H2O (710 mmH2O)

Service Manual – SC351 Scub Sytem - Disc 42

Scrub System, Disc

Functional Description
The disc brush system can be started by the operator.
The disc brush turns counter-clockwise.
The brush system, when turning, cleans/washes the floor surface and assists machine forward movement.
The deck, where brushes suitable for cleaning the particular type of floor are installed, is the main part of the
scrub system. The brush deck is fixed and integrated in the machine with a support bracket. The adjusting sys-
tems adjusts the forward speed, while the handwheel on the deck adjusts the machine straight-forward drive.
The brush working pressure is functional to the machine designed balance.
The brush motor (M1) is supplied by vacuum brush motor relay (K1) which is driven by the program selection
knob/rotary switch (SW1) when it is turned to 1, 2 or 3, and the machine start-up enabling push-button (SW2)
is pressed. The circuit is protected by the brush motor fuse (F1).
The system, once activated, uses the solution coming form the solution system, to wash the floor.
To work properly, the brush motor needs the following:
• Program selection knob/rotary switch (SW1) turned to 1, 2 or 3
• Machine start-up enabling push-button (SW2) pressed
• Charged batteries (the red LED must not be flashing).
• Battery charger is completing path to battery negative for B2
When necessary, to use the squeegee in the opposite direction, pry on the handlebar and slightly lift the deck
while the brush is turning. The rubber pads mounted into the deck allow the mechanical rotation by creating
friction on the rotating brush. When the deck is turned by 180° start to scrub/dry by drawing the machine.
To resume working in the normal forward direction, push the machine forward until the brush deck returns
to the original position.

Wiring Diagram

BRUSH MOTOR FUSE (F1) FUNCTION SELECTOR FUSE (F3)

PROGRAM SELECTION
KNOB/ROTARY SWITCH (SW1)
BATTERY CHARGER (CH)

BRUSH
MOTOR (M1)

M1
MACHINE START-UP
ENABLING
PUSH-BUTTON (SW2)
BRUSH MOTOR
RELAY (K1)

BRUSH MOTOR RELAY (K1)

P100793
Service Manual – SC351 Scub Sytem - Disc 43

Component Locations
• Brush deck • Machine straight forward movement adjusting
• Brush motor (M1) handwheel
• Drive hub • Deck rotation end of stroke system
• Machine forward speed adjusting handwheel

Machine straight
forward movement
adjusting handwheel

Brush motor (M1)

Machine forward
speed adjusting
handwheel

Brush deck

Drive hub

Deck rotation end of

stroke system

P100794
Service Manual – SC351 Scub Sytem - Disc 44

Component Locations (Continues)

• Brush motor fuse (F1)
• Brush motor relay (K1)

Brush motor fuse (F1)

Brush motor relay (K1)

P100781
Service Manual – SC351 Scub Sytem - Disc 45

Maintenance and Adjustments

Brush Cleaning

Warning! It is advisable to wear protective gloves when cleaning the brush because there may
be sharp debris.

1. Remove the brush.

2. Clean the brush with water and detergent.

3. Check the brush bristles for integrity and wear; if necessary, replace the brush.

Machine Speed Adjustment

Note: The machine speed and forward movement vary according to the type of floor to be
cleaned and the choice of using the brush or the pad.
If necessary, perform the adjustments as shown.

1. Remove the recovery and the detergent tanks.

2. Adjust the machine speed with the handwheel (A):

◦◦ Turn the handwheel counter-clockwise to increase the machine speed.
◦◦ Turn the handwheel clockwise to decrease the machine speed.

3. If it is difficult to keep the machine moving in a straight line because it deviates to the left or to the
right, adjust the handwheel (B) by turning it clockwise or counter-clockwise.

4. After adjusting, install the tanks.

5. With the machine ready to operate, perform hands-on tests of the machine and, if other adjustments are
necessary, repeat steps 1 to 4.

B
A

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Service Manual – SC351 Scub Sytem - Disc 46

Troubleshooting
Open Circuit
• The Brush motor fuse (F1) determines an open in the supply circuit of the brush deck motor. This protects
the circuits from being damaged under overload conditions.
• The open in the fuse can be caused by the following:
• Short circuit in the brush motor wiring harness; fault in the motor.

Trouble Possible Causes Remedy

The brush does not clean properly The brush is excessively worn Replace

The brush does not turn The motor is faulty Check the motor amperage/replace

There are ropes or debris restraining the brush rotation Remove and clean

The Brush motor fuse (F1) is open Replace

The brush motor relay (K1) is damaged Replace

The program selection knob/rotary switch (SW1) is broken Replace

The levers or the machine start-up enabling push-button Replace

(SW2) are broken

Warning! This procedure must be performed by qualified personnel only.

Service Manual – SC351 Scub Sytem - Disc 47

Brush Motor Amperage Check

1. Drive the machine on a level floor. 7. Turn off the brush by releasing the levers (40).

2. Remove the brush, as shown in the User 8. Turn the knob (32) to “0”.
Manual.
9. Remove the amp clamp (A).
3. Place two wooden shims (A) under the side area
of the deck as shown in the figure. Wooden shim 10. If the amperage is higher, perform the following
thickness must be 1.5 in (40 mm). procedures to detect and correct the abnormal
amperage:
◦◦ Check if there is dust or dirt (ropes, cables,
Warning! Keep the wooden shims at an
etc.) on the brush hubs.
appropriate distance from the
◦◦ Disassemble the motor (see the procedure in
brush hub.
the relevant paragraph), and check the condi-
tion of all its components.
4. Turn the knob on the brush activation program.
If the above-mentioned procedures do not lead to
5. Apply the amp clamp (A) on one cable (B) of the a correct amperage, the motor must be replaced
brush motor. (see the procedure in the relevant paragraph).
6. Turn on the brush by pressing the push-button
(39) together with the levers (40), then check
that the motor amperage (C) is 6 to 8 A at 12 V.

B C

P100796
Service Manual – SC351 Scub Sytem - Disc 48

Removal and Installation

Brush Deck Disassembly/Assembly

Disassembly B

1. Place the machine on a hoisting system (if A

available), then lift it. Otherwise, drive the
machine on a level floor.

2. Make sure that the battery connector is

disconnected.

3. Disconnect the vacuum hose from the squeegee

C
(A).

4. Lift the machine and remove the brush.

P100797
5. Remove the centre screw, remove the hub
assembly (B) and retrieve the transmission pin
key (C). F
6. Remove the 4 screws (D), the deck flange (E) and E
disassemble the brush deck (F).

7. Check the rubber pads (G) for integrity, and

replace them if excessively worn.

Note: The rubber pads (G) allow the

deck mechanical rotation by D
creating friction on the rotating
brush.

P100798
8. Check the end-of-stroke spacer tab (H) and
replace it if necessary.

9. Check the centre flange (I) and the relevant

springs for integrity, if necessary replace them. G
G
Note: The centre flange (I) absorbs
blows and vibrations between
the deck and the machine.
I
10. Upon reassembly, couple the centre flange with
the deck to match the reference arrows (J). H

P100799

J
P100800
Service Manual – SC351 Scub Sytem - Disc 49

Brush Deck Disassembly/Assembly (Continues)

11. Install the centre flange springs (K) by engaging
them on the deck housings and on the centre
flange housings (L) as shown in the figure. K

Assembly

12. Assemble the components in the reverse order of

disassembly and note the following:
◦◦ Couple the tooth (M) of the end-of-stroke
spacer tab (N) and the deck flange, as shown
in the figure.
◦◦ Assemble the brush deck by matching the P100801

deck flange polarization (O) with the one of

the deck holder (P).

Note: For further information on deck

components see the Spare Parts
List.

P100802

M
P100799

P100803
Service Manual – SC351 Scub Sytem - Disc 50

Brush Motor Disassembly/Assembly

Disassembly

1. Place the machine on a hoisting system (if

available), then lift it. Otherwise, drive the
machine on a level floor.

2. Make sure that the battery connector is

disconnected.

3. Disconnect the gearmotor connector (A) and the

detergent hose (B).

4. Lift the machine and remove the brush.

5. Disassemble the brush deck as shown by the

previous procedure.

6. Recover the key (C).

7. Remove the 4 screws (D).

P100804
8. Remove the gearmotor (E).

Assembly

9. Assemble the components in the reverse order of

disassembly.

Note: For further information on deck

components see the Spare Parts
List.

P100805
Service Manual – SC351 Scub Sytem - Disc 51

Specifications
Advance Nilfisk Nilfisk
Description
SC351 SC351 SC351 full PKG

Brush/pad diameter 14.5 in (370 mm)

Brush/pad pressure on the floor 39.6 lb (18 Kg)

Brush/pad pressure with full tank 59.5 lb (27 Kg)

Brush motor power 0.32 hp (240 W)

Brush motor speed 140 rpm

Service Manual – SC351 Solution System 52

Solution System

Functional Description
The solution system supplies the detergent to the brush when cleaning the floor. The solution tank is also the
main machine body. There is a manual valve on the left side of the tank to close the water supply whenever
maintenance must be performed on the machine.
The detergent quantity is adjusted by the operator with the solution flow switch (SW3). The solution flows
from the tank to the tap, through the filter and solenoid valve (EV) and then to the brush deck.
The solenoid valve (EV) is driven by the program selection knob/rotary switch (SW1) when it is turned to 1 or
2, and the machine start-up enabling push-button (SW2).
When the solution flow switch (SW3) is open the solenoid valve (EV) is driven by solenoid valve timer (KT1)
(2 sec. ON - 2 sec. OFF). When the solution flow switch (SW3) is closed the solenoid valve (EV) is always on
(by-pass the solenoid valve timer).
The circuit is protected by the function selector fuse (F3) on the LED electronic board (EB1).
The solenoid valve (EV) opening and closing time, according to the water flow, are shown below:

Solution flow switch (SW3) Solenoid valve (EV) ON time Solenoid valve (EV) OFF time
setting

0 2 sec 2 sec

1 Always ON -

Wiring Diagram

FUNCTION SELECTOR
FUSE (F3)

PROGRAM SELECTION
KNOB/ROTARY SWITCH (SW1)
BATTERY CHARGER (CH)

SOLENOID VALVE
TIMER (KT1)
MACHINE START-UP
ENABLING
PUSH-BUTTON (SW2)
SOLUTION FLOW
SWITCH (SW3)

SOLENOID VALVE (EV)

P100806
Service Manual – SC351 Solution System 53

Component Locations
• Solution tank • Solenoid valve (EV)
• Filler plug • Detergent hose
• Detergent valve

Filler plug

Solution tank

Detergent valve

Detergent hose

Solenoid valve (EV)

P100807
Service Manual – SC351 Solution System 54

Component Locations (Continues)

• Solenoid valve timer relay (KT1)

Solenoid valve timer

relay (KT1)

P200067
Service Manual – SC351 Solution System 55

Troubleshooting
Trouble Possible Causes Remedy

Small amount of solution or no solution The valve between tank and solution hose is clogged/dirty Clean
reaches the brush
The solenoid valve (EV) is faulty or the electrical Replace the solenoid valve or repair
connection is open the electrical connection

There is dust/debris in the tank or in the detergent hoses, Clean the tank/hoses
obstructing the solution flow

The function selector fuse (F3) is open Replace

The solenoid valve relay (KT1) is broken Replace

The program selection knob/rotary switch (SW1) is broken Replace

The levers or the machine start-up enabling push-button Replace

(SW2) are broken

The solution leaks when the machine is The solenoid valve (EV) is dirty/broken Clean/replace
off
Service Manual – SC351 Solution System 56

Removal and Installation

Solenoid Valve Disassembly/Assembly

Disassembly 6. Remove the screws (D) and recover the washers.

1. Place the machine on a hoisting system (if 7. Remove the solenoid valve (E) upwards.
available), then lift it. Otherwise, drive the
machine on a level floor. Assembly
2. Make sure that the battery connector is 8. Assemble the components in the reverse order of
disconnected. disassembly and note the following:
◦◦ When assembling the solenoid valve (E),
3. Remove the cover and the solution and recovery
the stamped arrow (F) must be tuned in the
water tanks.
direction of the solution flow as shown in the
4. Remove the solenoid valve power supply figure.
connector (A).

5. Disconnect the hoses (B) and (C) under the

machine.

A E
F

B D C

P100808
Service Manual – SC351 Solution System 57

Specifications
Advance Nilfisk Nilfisk
Description
SC351 SC351 SC351 full PKG

Solution tank capacity 2.9 USgal (11 litres)

One drop: 0.066 gpm (0.25 litres/min)

Min/max solution flow
Two drops: 0.13 gpm (0.5 litres/min)

Resistance solenoid valve 16 Ohm

Service Manual – SC351 Squeegee System 58

Squeegee System

Functional Description
The squeegee system cleans the liquid off the floor, which is then collected by the recovery system.
The squeegee is fastened to the brush deck by 2 hooks and the vacuum hose.
When the machine is running, the conformation of the squeegee and the brush deck rotation mechanism, assist
in the alignment and accurate vacuuming of the water from the floor. The 2 blades have different hardness:
- Front blade; with ruled side to convey the water towards the centre of the squeegee.
- Rear blade; smooth, to collect the water and dry the floor.
All 4 functional edges of each blade can be used before replacing the blade itself.
The design and the central duct make it easy for the squeegee to clear the water.
Service Manual – SC351 Squeegee System 59

Component Locations
• Squeegee
• Rear blade
• Rear elastic strap
• Front blade
• Front strap

Squeegee

Rear blade

Rear elastic strap

Front blade

Front strap

P100809
Service Manual – SC351 Squeegee System 60

Maintenance and Adjustments

Squeegee Cleaning
Note: The squeegee must be clean 5. Disengage the squeegee (B) from the deck.
and its blades must be in
6. Wash and clean the squeegee. In particular,
good conditions in order to
clean the compartments (C) and the vacuum
get a good drying.
hole (D).
Caution! It is advisable to wear
protective gloves when 7. Check the front blade (F) and the rear blade
cleaning the squeegee (G) for integrity, cuts and tears; if necessary
because there may be replace them (see the procedure in the following
sharp debris. paragraph).

1. Drive the machine on a level floor. 8. Assemble the components in the reverse order of
disassembly.
2. Check that the function selection knob is turned
to “0” and disconnect the battery connector.

3. Fully turn the brush/pad-holder deck counter-

clockwise.

4. Disconnect the vacuum hose (A) from the

squeegee.

F
A

D C E

B
P100810
Service Manual – SC351 Squeegee System 61

Squeegee Blade Check and Replacement

1. Clean the squeegee as shown in the previous 3. Install the squeegee (B) by carefully inserting
paragraph. the hooks (L) and the vacuum hole (M) in the
brush deck housings.
2. Check that the front blade (E) and the rear
blade (F) are integral and free from cuts and 4. Connect the vacuum hose (A) to the squeegee.
lacerations; if necessary replace them. Check
that the front edge (G) of the rear blade is not
worn; otherwise, overturn the blade to replace
the worn edge with an integral one. If the other
edges are worn too, replace the blade as shown:
◦◦ Remove the fastening strap (H) by disengag-
ing it from the fasteners (I).
◦◦ Replace (or overturn) the rear blade (F), then
reinstall the fastening strap.
◦◦ Remove the fastening strap (J) by disengag-
ing it from the fasteners (K).
◦◦ Replace (or overturn) the front blade (E),
then reinstall the fastening strap.

D
I
F
A J
K
J H

C E F
G

D C E K

L M

B H I
P100811
Service Manual – SC351 Squeegee System 62

Troubleshooting
Trouble Possible Causes Remedy

Leaving streaks on floor There is debris under the blade Remove

The squeegee blade edges are torn or worn Replace

Service Manual – SC351 Wheel System, Non-Traction 63

Wheel System, Non-Traction

Component Locations
• Rear wheels on fixed axle
• Castors on brush deck
• Rear wheels on brush deck

Castors on brush deck

Rear wheels on brush

deck

Rear wheels on fixed

axle

P100812
Service Manual – SC351 Wheel System, Non-Traction 64

Specifications
Advance Nilfisk Nilfisk
Description
SC351 SC351 SC351 full PKG

Diameter of wheels on fixed axle 8.4 in (214 mm)

Wheel pressure on the floor 72.5 psi (0.5 N/mm2)