Operating Instructions
Read and observe this Operating Instructions!
Vacuum pump system
with wireless remote control
SC 920G
KNF Neuberger GmbH
Alter Weg 3
D-79112 Freiburg
Germany
Phone ++49 / (0)7664 / 5909-0
Fax ++49 / (0)7664 / 5909-99
E-Mail: info@knf.de
www.knf.de
KNF 121308-121311 12/16
Translation of original Operating Instructions, english
Items including delivery:

Vacuum pump system including hand terminal (batteries
included)

Coated collection flasks (2 x)

Flask clamps (2 x)

Mains cable

USB cable for connecting vacuum pump system to PC

Power supply for hand terminal

Operating Instructions

Abbreviated instructions

CD with digital Operating Instructions and software for
operating the vacuum pump system with a PC

Allen key for transport fastener
Transport fastener
The hand terminal is fastened in place at the factory, to prevent
damage during transport.
To remove the hand terminal, it is first necessary to release the
transport fastener. For further details, see chapter
6. Installation and connection.
Translation of original Operating Instructions, english, KNF 121308-121311 12/16
Vacuum Pump System SC 920G
Content
Content
Page
1. About this document
1.1. Using the Operating Instructions
1.2. Symbols and Markings
2. Use 5
2.1. Proper Use
2.2. Improper Use
3. Safety
4
4
4
5
5
6
4. Technical Data
8
4.1. Vacuum pump system
8
4.2. Vacuum pump system’s hand
terminal
10
4.3. Software
10
5. Design and Function
11
5.1. Vacuum pump system overwiew 11
5.2. Vacuum pump system functions 13
5.3. Hand terminal
15
5.4. Pump
16
5.5. Gas ballast
16
6. Installation and connection
17
6.1. Installation
17
6.2. Connection
18
7. Operation
19
7.1. Start up
19
7.2. Taking system out of operation 22
8. Operating vacuum pump system 23
8.1. Hand terminal
23
8.1.1. General functions and displays 23
8.1.2. Operation
25
8.1.3. Changing batteries on the hand
terminal
31
8.2. Operation without hand terminal 32
8.3. Software
32
9. Servicing
33
9.1. Servicing Schedule
33
9.2. Cleaning
33
9.2.1. Flushing Vacuum pump system 33
9.2.2. Cleaning Vacuum pump system 33
9.2.3. Emptying collection flask on the
suction and pressure sides
33
9.3. Changing Diaphragms and Valve
Plates
35
9.4. Replace overpressure valve on
high performance condenser
39
10. Troubleshooting
40
11. Ordering Information
45
12. Returns
46
13. Health and safety clearance and
decontamination form
47
Translation of original Operating Instructions, english, KNF 121308-121311 12/16
About this document
Vacuum Pump System SC 920G
1.
About this document
1.1. Using the Operating Instructions
The Operating Instructions are part of the vacuum pump system.
 Carefully study the Operating Instructions before using a
vacuum pump system.
 Always keep the Operating Instructions handy in the work area.
 Pass on the Operating Instructions to the next owner.
Project systems
Customer-specific project systems (systems which begin with “PJ”
or “PM”) may differ from the Operating Instructions.
 For project systems, also observe the agreed upon
specifications.
Compliance with the Operating Instructions is essential for the
safe and reliable operation of the vacuum pump system.
Failure to do so may result in damage or injury.
1.2. Symbols and Markings
Warning
A danger warning is located here.
Possible consequences of a failure to observe the
warning are specified here. The signal word, e.g.
WARNING Warning, indicates the danger level.
 Measures for avoiding the danger and its
consequences are specified here.
Danger levels
Signal word Meaning
DANGER
warns of
immediate danger
WARNING
CAUTION
Consequences if not observed
Death or serious injuries
and/or serious damage are the
consequence.
warns of possible
Death or serious injuries
danger
and/or serious damage are
possible.
warns of a possibly Minor injuries or damage are
dangerous
possible.
situation
Tab. 1
Other information and symbols
 An activity to be carried out (a step) is specified here.
1. The first step of an activity to be carried out is specified here.
Additional, consecutively numbered steps follow.
This symbol refers to important information.
4
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
Vacuum Pump System SC 920G
Use
2.
Use
2.1. Proper Use
The SC 920G vacuum pump system is designed for use in
chemical, pharmaceutical, and biological laboratories. The vacuum
pump system is exclusively intended for transferring gases and
vapors.
Make sure that the installation location is dry and the pump/system
is protected against rain, splash, hose and drip water.
Vacuum pump system is solely for use in indoor areas.
Owner's responsibility
Operating parameters and
conditions
Only install and operate the vacuum pump system under the
operating parameters and conditions described in chapter 4,
Technical data.
Protect vacuum pump system against humidity.
Requirements for
transferred medium
Before using a medium, check the compatibility of the materials of
the pump head, diaphragm, valves, sealings and tubing with the
medium.
Before using a medium, check whether the medium can be transferred danger-free in the specific application case.
Only transfer gases which remain stable under the pressures and
temperatures occurring in the pump.
High performance condenser
The high performance condenser must be installed on the outlet
side of the pump; if it is installed on the inlet side there is a danger
of implosion.
Observe the correct usage of the gas- and cooling liquidconnections on the high performance condenser. Inlet and outlet
connections for the gas are not interchangeable.
Accessories
Laboratory equipment or additional components connected to a
vacuum pump system have to be suitable for use with the pneumatic capabilities of the vacuum pump system (see chapter 4,
page 8).
2.2. Improper Use
The vacuum pump system may not be operated in an explosive
atmosphere.
The vacuum pump system is not suitable for transferring dusts.
The vacuum pump system is not suitable for transferring liquids.
The vacuum pump system must not be used if the entry of air or
gas into the vacuum pump system during venting (vent valve)
could result in the creation of reactive, explosive or otherwise
hazardous mixtures (e.g. with the medium).
The vacuum pump system must not be used to create vacuum and
overpressure simultaneously.
An overpressure must not be applied to the suction side of the
vacuum pump system.
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
5
Safety
Vacuum Pump System SC 920G
3.
Safety
The vacuum pump system is built according to the generally recognized rules of technology and in accordance with the occupational
safety and accident prevention regulations. Nevertheless, dangers
can result during their use which lead to injuries to the user or
others, or to damage to the vacuum pump system or other property.
Only use the vacuum pump system when it is in a good technical
and proper working order, in accordance with its intended use,
observing the safety advice within the operating instructions, at all
times.
Personnel
Make sure that only trained and instructed personnel or specially
trained personnel work on the vacuum pump system. This
especially applies to assembly, connection and servicing work.
Make sure that the personnel has read and understood the operating instructions, and in particular the "Safety" chapter.
Working in a safetyconscious manner
Observe the accident prevention and safety regulations when performing any work on the vacuum pump system and during operation.
Do not expose any part of your body to the vacuum.
Open housing parts with notice sticker (see fig. 1) only after separating mains plug from power source.
Fig. 1: Notice sticker
Correct match between hand
terminal and vacuum pump
system
Ensure that the employees check that the hand terminal is the right
one for this particular system before using a SC 920G vacuum
pump system. Vacuum pump systems are equipped with a paging
system for this purpose (see Actuating the vacuum pump system,
page 29).
Handling dangerous media
When transferring dangerous media, observe the safety regulations when handling these media.
Handling flammable media
Be aware that the vacuum pump system is not designed to be
explosion-proof.
Make sure the temperature of the medium is always sufficiently
below the ignition temperature of the medium, to avoid ignition or
explosion. This also applies for unusual operational situations.
Note that the temperature of the medium increases when the pump
compresses the medium.
Hence, make sure the temperature of the medium is sufficiently
below the ignition temperature of the medium, even when it is
compressed to the maximum permissible operating pressure of the
vacuum pump system. The maximum permissible operating pressure of the vacuum pump system is stated in the technical specifications (see chapter 4, page 8).
If necessary, consider any external sources of energy, such as
radiation, that may add heat to the medium.
In case of doubt, consult the KNF customer service.
6
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Vacuum Pump System SC 920G
Ventilating the vacuum pump
system
Environmental protection
Standards
Safety
When ventilating the vacuum pump system with air or inert gas, be
sure to prevent formation of reactive or explosive media. The
maximum permissible operating pressure at the ventilation
connection (Fig 2/5, page 11) is 0.1 bar g.
Store all replacement parts in a protected manner and dispose of
them properly in accordance with the applicable environmental
protection regulations. Observe the respective national and international regulations. This especially applies to parts contaminated
with toxic substances.
The vacuum pump system SC 920G conforms to the Directive
2011/65/EU (RoHS2).
The vacuum pump system SC 920G conforms to the safety
regulations of the EC Directive 2014/30/EU concerning
Electromagnetic Compatibility and the EC Directive 2006/42/EC
concerning Machinery. The requirements of the following
harmonised standards are fulfilled:

DIN EN 61010-1

DIN EN 61326-1 – class A

DIN EN 50581
The pumps correspond to DIN EN 60664-1:
Customer service and
repairs

the overvoltage category II

the pollution degree 2
Only have repairs to the vacuum pump system carried out by the
KNF Customer Service responsible.
Only authorized personnel should open those parts of the housing
that contain live electrical parts.
Use only genuine parts from KNF for servicing work.
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
7
Technical Data
Vacuum Pump System SC 920G
4.
Technical Data
4.1. Vacuum pump system
Materials for parts contacting the medium
Pump head
Diaphragms
Valves
Sealings
Hose connectors
Tubing
Pressure sensor
Venting valve
Valve block
Gas ballast valve
PPS
PTFE-coated
FFPM
FPM
PVDF
®
Norprene
Ceramics
FFPM
PP
PVDF
Pneumatic performance
Max. permissible operating
pressure [bar g]
Ultimate vacuum [mbar abs.]
Delivery rate at atm. pressure
[l/min]*
Max. permissible pressure at
inert gas connection [bar g]
0
≤2
≤ 5 with open gas ballast
0-21 (controllable)
0.1
Ambient and media temperature
Permissible
+ 10 °C to + 40 °C
ambient temperature
Permissible media temperature + 10 °C to + 40 °C
Other parameters
Vacuum connection and gas
outlet
Ventilation connection
Weight of vacuum pump
system, including hand
terminal [kg]
Dimensions:
width x height x length [mm]
Maximum permissible ambient
relative humidity
Maximum altitude of site
[m above sea level]
Tab. 2 (part 1)
8
For tube ID 10 mm
For tube ID 6 mm
15.2
366 x 423 x 294
80 % for temperatures up to
31°C, decreasing linearly to
50 % at 40°C
2000
*Liters in standard state (1,013 mbar at 0 °C)
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Vacuum Pump System SC 920G
Technical Data
Operating parameters of coolant (high performance condenser)
Max. permissible pressure
[bar g]
Permissible temperature
Coolant connections on highpeformance condenser
2
Coolant-wetted surface [cm ]
3
- 15 °C to + 20 °C
For tube ID 8 mm
Min. 460
Electrical data vacuum pump system
Voltage** [V]
Frequency [Hz]
Max. current consumption at
100 V / 115 V / 240 V [A]
Max. watt consumption [W]
Protection class
Fuse vacuum pump system [A]
Drive motor fusing
Tab. 2 (part 2)
100-240 +/- 10 %
50/60
1.7 / 1.5 / 0.8
135
IP20
2 x T2.5
Electronic overcurrent protection
** Automatic voltage selection
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
9
Technical Data
Vacuum Pump System SC 920G
4.2. Vacuum pump system’s hand terminal
Dimensions:
width x height x length [mm]
Weight [kg]
90 x 205 x 55
Operating voltage
12 V DC
Current consumption
1.25 A
Wireless connection's
frequency band
Wireless range
2.4 GHz
Power supply
0.51
About 50 m without obstacles,
about 10 m through walls
Through integrated batteries or
power supply (in delivery
included)
DC charging socket
Chargeable batteries
Battery service life*
Charging time*
Tab. 3
External diameter: 6.3 mm
Inside diameter: 2 mm
4 x round AA 1.2 V 2500 mAh,
fast-charging; see spare parts
list in chapter 11
Up to 12 hours, depending on
number of entries and data
transmission
about 7 h
* Applies to standard included batteries
When charging the hand terminals of the SC 920G vacuum
pump system, use only the original power supply from KNF.
Several different vacuum pump systems may be operated
simultaneously with their respective hand terminals within the
wireless connection range.
The wireless connection between hand terminal and vacuum
pump system is robustly resistant to operation of mobile
telephones and Bluetooth devices in the immediate area.
4.3. Software
The USB connection between the PC and the vacuum pump
system is operated as an RS232 interface. Accordingly, in the
operating system it is managed as an additional COM connection
and can be addressed with conventional terminal software. Please
see the delivered CD for information on operating the vacuum
pump system via software.
10
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
Vacuum Pump System SC 920G
Design and Function
5.
Design and Function
5.1. Vacuum pump system overwiew
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Carrying handle
Hand terminal (removable;
signals transmitted
wirelessly)
Set screw of transport
fastener
High-performance
condenser
Gas ballast switch
Ventilation connection
Vacuum chamber
connection (gas inlet)
Hexagonal gland
Pump
Base
Flask clamp for 12
Suction-side condensation
collection flask (coated)
Mains switch
Hand terminal dock
Pressure-side condensation collection flask (coated)
Flask clamp for 15
Gas outlet
Pin of transport fastener
Coolant connection on
high-performance
condenser (feed)
Coolant connection on
high-performance
condenser (return)
Fig. 2: Vacuum pump system SC 920G
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
11
Design and Function
1
2
3
4
Vacuum Pump System SC 920G
USB port for connecting
vacuum pump system to
PC
Coolant valve connection
Mains plug connection
Fuse drawer
Fig. 3: Plug strip on rear of base (Fig. 2/10)
The vacuum pump system generates a vacuum that can be controlled either through the hand terminal (see chapter 5.3, page 15)
or a PC.
Collection flask (Fig. 2/12) collects on the suction side of the pump
particles and drops that were, contrary to the requirements of the
pump, suctioned from the vacuum chamber. The collection flask is
coated (implosion protection) and fastened to the vacuum pump
system via a flask clip.
The high-performance condenser at the pump outlet once again
recollects solvents from the pumped gas instead of allowing it exit
into the environment or fume hood. The high-performance condenser is surrounded by a shell for temperature insulation and
explosion protection.
Solvents deposited in the high-performance condenser are collected in the coated (for explosion protection) collection flask (Fig.
2/15). A flask clip secures the glass flask to the condenser flange.
A recirculating cooler or continuously flowing cold water cools the
high-performance condenser to the condensation temperature.
12
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Vacuum Pump System SC 920G
Design and Function
5.2. Vacuum pump system functions
The vacuum pump system can be operated in four different modes:

Evacuate
The vacuum pump system evacuates a vacuum chamber with
adjustable pump capacity.

Pressure control
The vacuum pump system controls system pressure to the setpoint pressure value (constant pressure).

Automatic
The vacuum pump system independently finds the sample's
vapor pressure and adjusts process pressure accordingly.

Function
The vacuum pump system controls pressure according to the
entered pressure curve. Up to 10 different pressure curves can
be stored. The following process parameters can be entered:

Setpoint pressure at various time points after starting the
process

Coolant valve (accessory) ON and OFF with time point
after start of process

Option "Jump" with time after the start of the process:
The system evacuates/ventilates to the required pressure
as quickly as possible.

Option "Automatic" with time after the start of the process:
Automatic detection of the boiling pressure
If the set limit pressure is reached without a vapor
pressure, the program goes to the next function step.

Option "Automatic Plus" with time after the start of the
process:
Automatic detection of the vapor pressure with subsequent
pressure reduction.
At any time during an active process, you can switch to manual
process control. Functions for Evacuate and Pressure control will
be available simultaneously. When activating manual process control, the current actual pressure will be adopted as the first setpoint
pressure. In other words, process pressure will be initially "frozen"
at the current value.
The operating modes can be combined in any way for the purposes of intelligent process control. For example, after successful
boiling point detection in the automatic mode, the following operating modes are available for specific distilling off of the solvent
recovered:

Evacuation
(constant vaporization rate for optimum condenser capacity
utilization)

Function
(Following a preset pressure ramp provided in order to attain a
separation from components with higher boiling points)
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
13
Design and Function
Vacuum Pump System SC 920G

Manual process control
(active control of the distillation using the setpoint pressure)
In order to change to another operating mode, the process is first
stopped and then restarted in the new operating mode.
Gas ballast
14
The gas ballast switch (Fig. 2/5) can be used to open and close the
gas ballast valve on the vacuum pump system's pump (see
Chapter 5.5).
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
Vacuum Pump System SC 920G
Design and Function
5.3. Hand terminal
Basic elements
1
2
3
4
5
Upper grip
Touchscreen
I/O switch
DC input 12 V
Rotary/push knob for

adjusting pump speed
and setpoint pressure

switching to manual
operation
Fig. 4: Hand terminal
Function
The hand terminal is used to set process parameters with which
the vacuum pump system will control pressure.
Settings can be made on the hand terminal's touchscreen (2) and
with the rotary/push knob (5).
To operate the vacuum pump system remotely, remove the hand
terminal from the holder (see chapter 8.1.1, page 23) on the
vacuum pump system. This provides a convenient way to operate
the vacuum pump system when it is in a cabinet or under a closed
fume hood.
Whenever the hand terminal is located in the holder while the
vacuum pump system is turned on, the batteries in the hand
terminal will charge automatically. This happens even when hand
terminal is switched off. Alternatively, the batteries can be charged
through the hand terminal's power supply (see DC input (4)). As a
result, it is not necessary to place the vacuum pump system where
it is easily accessible for the user.
The power supply also makes it possible to supply the hand terminal with electrical power directly from a mains connection.
An acoustic alarm sounds on the hand terminal when the battery
charge levels are low.
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
15
Design and Function
Vacuum Pump System SC 920G
5.4. Pump
Design
1
2
3
4
5
6
7
Outlet valve
Inlet valve
Transfer chamber
Diaphragm
Eccentric
Connecting rod
Pump drive
Fig. 5: Pump design
Function Diaphragm pump
Diaphragm pumps transfer, compress (depending on pump
version) and evacuate gases and vapors.
The elastic diaphragm (4) is moved up and down by the eccentric
(5) and the connecting rod (6). In the downward stroke it aspirates
the gas to be transferred via the inlet valve (2). In the upward
stroke, the diaphragm presses the medium out of the pump head
via the outlet valve (1). The transfer chamber (3) is hermetically
separated from the pump drive (7) by the diaphragm.
5.5. Gas ballast
Personal injury caused by poisoning or explosion
and damage to the pump
 Make sure that no reactive or explosive mixtures
will be produced when the gas ballast valve is
WARNING
open.
Fig. 6: Gas ballast switch
When transferring vaporous media, opening the gas ballast
valve can minimize the formation of condensation in the pump
heads.
Opening the gas ballast valve deteriorates ultimate vacuum
performance.
The gas ballast valve is opened and closed via the gas ballast
switch (see Fig. 6).
Please contact KNF Service if you require an inert connection for
the gas ballast.
16
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
Vacuum Pump System SC 920G
Installation and connection
6.
Installation and connection
 Only install the vacuum pump system under the operating
parameters and conditions described in chapter 4, Technical
data, page 8).
 Observe the safety precautions (see chapter 3, page 6).
6.1. Installation
 Before installation, store the vacuum pump system at the
installation location to bring it up to room temperature.
Cooling air supply
 Install the vacuum pump system so that the motor fan of the
pump can intake sufficient cooling air.
Installation location
 Make sure that the installation location is dry and the vacuum
pump system is protected against rain, splash, hose and drip
water.
 Choose a safe location (flat surface) for the vacuum pump
system.
 Protect the vacuum pump system from dust.
 Protect the vacuum pump system from vibrations and jolts.
Connected components
 Only connect components to the vacuum pump system which
are designed for the pneumatic data of the vacuum pump system (see chapter 4, page 8).
Coolant for high-performance
condenser
A recirculating cooler or flowing cold water (or another cooling
medium) is needed to cool the high-performance condenser to the
condensation temperature.
Removing the transport
fastener
 The hand terminal is fastened in place at the factory, to prevent
damage during transport. To remove the hand terminal, it is
first necessary to release the transport fastener.
1. Loosen the set screw (Fig. 2/3, p. 11).
2. Pull out the pin of the transport fastener (Fig. 2/18, p. 11) as far
as the limit stop.
3. Tighten the set screw again.
The transport fastener can be reattached for any future
transport operations.
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17
Installation and connection
Vacuum Pump System SC 920G
6.2. Connection
1.
Connect the vacuum chamber to the gas inlet's hose connector (Fig. 2/7, page 11, for hose inside diameter of 10 mm). For
this, vacuum tubing must be used.
2.
Connect hose to high-performance condenser in order to
discharge gas exhaust (Fig. 2/17, page 11).
Danger of high performance condenser bursting.
The high-performance condenser is not pressureproof.
CAUTION
 Do not reduce or regulate the quantity of gas at
the gas outlet, and do not install any components that hinder the gas flow.
Safely discharge gas exhaust so that no gas can escape into
the ambient air.
Make sure that the high-performance condenser’s gas outlet is
not blocked (high-performance condenser is not pressureproof).
3.
Attach coolant feed and return to high-performance condenser
(Fig. 2/19 and 20, page 11).
Connect only the KNF coolant valve (see Chapter 11.2,
Accessories) to the coolant valve connection (Fig. 3/2, page
12). Consult with KNF before using any other valves.
18
4.
If necessary: Connect inert gas supply to ventilation connection (Fig. 2/6, page 11). Observe the safety instructions in
chapter 3.
5.
Insert the power cable plug into a properly installed shockproof
socket.
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Vacuum Pump System SC 920G
Operation
7.
Operation
7.1. Start up
Before switching on the vacuum pump system, observe the
following points:
Operational requirements
 All hoses attached properly

Fan openings not blocked

Specifications of the power supply correspond with the data
on the vacuum pump system’s type plate.

Recirculating cooler or cold water connection ready on highperformance condenser.

The high-performance condenser's gas outlet is not blocked
(high-performance condenser is not pressure-proof).

Vacuum pump system is at room temperature.

Vacuum pump system and hand terminal belong together.

No reactive, explosive or otherwise hazardous mixtures may
be produced when ventilating the vacuum system through the
air inlet (Fig. 2/6, page 11) (if necessary, use an inert gas)

When the gas ballast valve is open, no reactive, explosive, or
otherwise hazardous mixtures can form (otherwise, contact
KNF Service).
Tab. 4
 Only operate the vacuum pump system under the operating
parameters and conditions described in chapter 4, Technical
data (page 8).
 Make sure the vacuum pump system is used properly (see
chapter 2.1, page 5).
 Make sure the vacuum pump system is not used improperly
(see chapter 2.2, page 5).
 Observe the safety precautions (see chapter 3, page 6).
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19
Operation
Vacuum Pump System SC 920G
Uncontrolled operation may result in personal injury
and damage to the vacuum pump system.
DANGER
When using several vacuum pump systems, there is
the danger of confusing them, which can result in
undesired interference into other processes: The
transmission of commands from the wrong hand
terminal for the vacuum pump system may trigger an
uncontrolled response in the vacuum pump system
that the terminal controls.
 Every time a vacuum pump system is used with
a hand terminal, it is essential to ensure a
correct match between the two components. Use
the paging function for this purpose (see
Actuating the vaccum pump system, page 29).
 Additionally it is possible to use color stickers to
indicate which hand terminal belongs to which
vacuum pump system (see chapter 11. Ordering
information).
Uncontrolled operation may result in personal injury
and damage to the vacuum pump system.
If the wireless connection between the hand terminal
WARNING and vacuum pump system is broken, the vacuum
pump system will continue to operate with the current settings.
 Immediately determine and remove the cause of
the interruption between the hand terminal and
vacuum pump system (chapter 10, page 40).
 If you are not able to reestablish wireless
contact, replace the hand terminal back to the
vacuum pump system (chapter 8.1.1, page 23).
The vacuum pump system can also be operated
directly and the ventilation valve and coolant
valve can be opened and closed directly
(chapter 8.2, page 32).
Personal injury caused by poisoning or explosion
and damage to the vacuum pump system.
 Make sure that no reactive or explosive mixtures
will be produced when ventilating the vacuum
WARNING
pump system through the air inlet.
20
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Vacuum Pump System SC 920G
Operation
Hazard of the vacuum pump system bursting due to
excessive pressure increase
WARNING
 Do not exceed max. permissible operating
pressure (0 bar).
 Monitor pressure during operation.
 If the pressure exceeds the maximum permissible operating pressure, immediately shut down
vacuum pump system and eliminate fault (see
chapter 10, page 40).
Personal injury caused by poisoning or explosion
and damage to the pump.
 Make sure that no reactive or explosive mixtures
will be produced when ventilating the vacuum
WARNING
system through the air inlet.
 Make sure that the media are compatible with
each other (when running two different
processes simultaneously).
Danger of high performance condenser bursting.
The high-performance condenser is not pressureproof.
CAUTION
 Make sure that the high performance
condenser’s gas outlet is not blocked.
In order for the high-performance condenser to recover solvent
from the delivered gas, it must be cooled by means of a cold
water supply or recirculating cooler.
When using a coolant valve:
Danger of the high performance condenser bursting
 Make sure that the coolant valve is mounted
between the coolant supply and the coolant inlet
port of high performance condenser.
WARNING
Pump standstill
Inspect and empty collection
flasks
With the pump at a standstill, open pressure and suction lines to
normal atmospheric pressure
At appropriate intervals, inspect the fill level in the condensation
collection flasks located on the suction and pressure sides of the
vacuum pump system (Fig. 2/12 and 15, page 11). When needed,
empty the collection flasks; properly dispose contents.
Switching vacuum pump system on
The vacuum pump system may not start up against overpressure during switch-on. During operation as well, there may be
no overpressure in the pneumatic lines. If a pump starts against
pressure, it may block. This activates the thermal switch, and
the pump switches off.
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
21
Operation
Vacuum Pump System SC 920G
 Switch on vacuum pump system at mains switch (Fig. 2/13,
page 11).
 Switch on hand terminal at its I/O switch (see Fig. 4/3, page
15).
Refer to chapter 8, page 23, for information on operating the
vacuum pump system.
7.2. Taking system out of operation
 Stop the ongoing process.
 When transferring aggressive media, flush the vacuum pump
system prior to switch-off to increase the service life of the
diaphragms (see chapter 9.2.1, page 33).
 Switch off vacuum pump system with mains switch (see fig. Fig.
2/13, page 11).
 Switch off hand terminal at its I/O switch (see Fig. 4/3, page
15).
Uncontrolled operation may result in personal injury
and damage to the vacuum pump system.
If the hand terminal is switched off while the vacuum
WARNING pump system remains switched on, the vacuum
pump system will continue to operate with the current settings.
 Always switch the vacuum pump system off
when done working.
22
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
Vacuum Pump System SC 920G
Operating vacuum pump system
8.
Operating vacuum pump system
8.1. Hand terminal
8.1.1. General functions and displays
1
2
3
4
5
Upper grip
Touchscreen
I/O switch
DC input 12 V
Rotary/push knob for

adjusting pump speed
and setpoint pressure

switching to manual
operation
Fig. 7: Hand terminal
The vacuum pump system is operated via the hand terminal with
the aid of:

a rotary/push knob

a touchscreen.
The rotary/push knob has the following functions:

Rotate: Changes pump capacity or the selected pressure
setting (depending on selected operating mode).

Press: Interrupts the active process and switches into manual
process control (pressing effects an evacuation in this case).
Touchscreen contents:

Display of the most important process variables (Fig. 8, page
25).

Menu for selecting operating mode and units for pressure
display (Fig. 9, page 25).

Operating buttons (Fig. 9, page 25) with the following functions:

Start and stop the process;

open and close the ventilation valve;

open and close the high-performance condenser's coolant
valve (accessory).
Removing and replacing the hand terminal
To remove the hand terminal from the vacuum pump system:
grasp the upper grip of the hand terminal (Fig. 7/1) and pull until it
releases, and then remove it.
Replacing the hand terminal:
Insert the bottom of the terminal into the holder provided in the
vacuum pump system (Fig. 2/14, page 11); then push firmly on the
upper grip of the terminal (Fig. 7/1) until it clicks into place.
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
23
Operating vacuum pump system
Vacuum Pump System SC 920G
Whenever the hand terminal is located in the holder while the
vacuum pump system is turned on, the batteries in the hand
terminal will charge automatically. This happens irrespective of
whether the hand terminal is switched on or off.
Every time you use a hand terminal, check to ensure a correct
match between the terminal and the vacuum pump system.
Use the paging system for this purpose (see Actuating the
vacuum pump system, page 29).
Displays
1 Battery:
- Charging
- Charging status
2
3
4
5
6
7
Connection to vacuum
pump system
- Direct connection
- Wireless connection
Process time
Actual pressure in selected
pressure unit (or „No
connection“, if no wireless
connection to vacuum
pump system)
Process active
Capacity in percent or
setpoint pressure in
selected pressure unit
(depending on operating
mode)
Explanation of rotary/push
knob functions
(Rotate: change capacity; Press:
interrupt operating mode and
switch to manual process control)
8
9
Only in Automatic operating
mode
Automatic with pressure
reduction
Only in Automatic operating
mode
Automatic pressure
reduction active
Fig. 8: Display on the touchscreen
24
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
Vacuum Pump System SC 920G
Operating vacuum pump system
Menus and buttons
1 Operating mode menu
2 Pressure units menu
3 Button Actuating the vacuum pump system (Paging)
4 Button for ventilation valve:
ON = To open
CLOSE = To close
5 Button for coolant valve
(accessory) at highperformance condenser:
ON = To open
CLOSE = To close
6 Button for the process:
START = To start
STOP = To stop
7 Button for automatic
pressure reduction:
Press = Finish (the current
pressure is applied as the
setpoint pressure)
Fig. 9: Menus and buttons on the touchscreen
8.1.2. Operation
Menu language
When the start page appears after switching the hand terminal on,
choose between the following languages: German, English, French,
Italian, Spanish, Dutch, Japanese, and Chinese. The selection can
be made only immediately after switching on.
Pressure unit
Process pressure can be displayed on the hand terminal in mbar,
bar, hPa, or Torr.
Use the Pressure units menu to select the pressure units (button
on touchscreen; see Fig. 10).
Pressure units can be changed only when no process is active.
In order to change the unit of pressure, it is necessary to
temporarily switch to another operating mode.
Fig. 10: Pressure units menu
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
25
Operating vacuum pump system
Vacuum Pump System SC 920G
Operating modes
The current operating mode is displayed at the top of the hand
terminal's touchscreen. Press on this line of the touchscreen to
open the menu for changing operating mode (see Fig. 11, at the
top).
Operating mode can be changed only when no process is
active.
Switching to manual process control (Break)

Press briefly on the rotary/push knob:
Manual process control; actual pressure will be adopted as the
setpoint pressure and actively controlled.
Within the manual process control

Press on the rotary/push knob:
Vacuum pump system will evacuate.

Let go:
Actual pressure will be adopted as setpoint pressure.

Rotate:
Changes setpoint pressure.
Fig. 11: Operating mode menu
26
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
Vacuum Pump System SC 920G
Operating vacuum pump system
Starting and stopping the process
Pressing the START button starts a process.
Pressing the STOP button stops a process.
Open and close the ventilation valve
Personal injury caused by poisoning or explosion
and damage to the vacuum pump system
 Ensure that the creation of reactive, explosive or
otherwise hazardous mixtures during the supply
WARNING
of air is prevented.
Pressing the ON button for ventilation valve (left button below)
opens the ventilation valve.
If the ON button is pressed for more than 3 seconds, the
ventilation valve remains open.
If the ventilation valve is permanently open (OFF button shown in
display), it can be closed again with the OFF button.
Opening and closing coolant valve (accessory)
Pressing the ON button for coolant valve (right button below)
opens the coolant valve on the high-performance condenser.
Pressing the OFF button for the coolant valve closes the coolant
valve on the high-performance condenser.
Entering value in Evacuate operating mode
Use the rotary/push knob to set pump capacity.
Entering value in Pressure control operating mode
Use rotary/push knob to set desired pressure.
Entering value in Automatic operating mode
Not necessary to enter value.
If a boiling point is detected in Automatic mode, after the system
regulates to this pressure, the pressure is reduced automatically to
speed up evaporation of the solvent (see Fig. 12).
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
27
Operating vacuum pump system
Vacuum Pump System SC 920G
1.) Start Automatic
operating mode
2.) Boiling point detected;
system regulates to this
pressure
3.) Automatic pressure
reduction
Fig. 12: Automatic function sequence
If you press the arrow key (see Fig. 9/7) during automatic
pressure reduction, the current pressure is applied as the new
setpoint pressure and the vacuum pump system regulates to
this pressure. The current setpoint pressure is shown in the
display in place of the arrow.
If you press again on the setpoint pressure value, automatic
pressure reduction is reactivated and the arrow appears in the
display after about 25 seconds.
Entering value in Function operating mode
The desired pressure curve is entered via data points that connect
the vacuum pump system to pressure ramps.
Fig. 13: Menu for Function operating mode
Entering data points (up to 12):
1.
28
Time interval since the last data point: ∆ t
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
Vacuum Pump System SC 920G
Operating vacuum pump system
2.
Setpoint pressure: p (mbar) / p (bar) / p (hPa) / p (Torr)
3. Additional options ("+" column) to influence the course of the
function:

CV1: Open coolant valve (accessory):

CV0: Close coolant valve (accessory):
 S: Jump – the system evacuates/ventilates to the required
pressure as quickly as possible.
 A: Automatic – Automatic detection of the boiling pressure
If the set limit pressure is reached without a vapor pressure,
the program goes to the next function step.
 A+: Automatic Plus – Automatic detection of the vapor
pressure with subsequent pressure reduction.
Line selection (see Fig. 13):

To change the line:
Turn the rotary/push knob.

To select a line for editing:
Press the rotary/push knob.
To edit a selected line:

To change columns:
(e.g. from ∆ t to p (mbar):
Press the rotary/push knob.

To change an entry:
Turn the rotary/push knob.
After the last column (+), the display automatically returns to
line selection and jumps to the next line.
If you are in input mode and have not entered any data within 3
seconds, the display automatically returns to line selection.
The function values of the data point table are stored in the
internal memory of the vacuum pump system when the
process starts, and are available again when there is a restart.
Changes to the function values (sampling point table) are
carried over directly from the PC software, which may be used
simultaneously.
Repeating/deleting sampling points:
The following symbols may be set in the column for the time
intervals under the value 00:00:00:

= Repetition. The desired number of repetitions can now
be specified in the field for the setpoint pressure.

… = Deletion of the data point.
In both cases, all subsequent sampling points are automatically
deleted.
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
29
Operating vacuum pump system
Vacuum Pump System SC 920G
Calling the stored data point tables:

Press the button to select data point tables (arrow in Fig. 13)
and select the required data point table.
You can now see the data point table that is stored under the
number.
Up to 10 different data point tables can be stored and called as
required. The number in the display (arrow in Fig. 13) indicates
the data point table that is currently selected.
Actuating the vacuum pump system (Paging)
When you press the circle symbol for the active process (Fig. 8/5,
page 25) in the hand terminal display, the LED next to the page
button (Fig. 15, page 32) on the vacuum pump system will blink.
The other way around, the hand terminal will answer with a signal
tone if you press the paging button of the vacuum pump system
(see chapter 8.2, page 32).
No wireless connection
If there is no wireless connection between the hand terminal and
the related vacuum pump system (for example if the vacuum pump
system is not switched on or the wireless connection is being
established or is interrupted):

The message "No connection" will blink in the hand terminal's
display (see figure 14);

An audible warning will be emitted if a button on the touchscreen is pressed.
Refer to chapter 10, table 9 for tips on resolving this problem.
Fig. 14: Display „No connection“
30
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
Vacuum Pump System SC 920G
Operating vacuum pump system
8.1.3. Changing batteries on the hand terminal
ESD-sensitive devices (ESDS)
CAUTION
The nonobservance of the ESD-protection
specifications under the IEC 61340-5-1 can lead to a
partly or total defect of the hand terminal.
 Only handle the hand terminal at an ESDprotected area (EPA) by a qualified person
under the IEC 61340-5-1 directive.
1.
Loosen the four screws on the underside of the hand terminal.
2.
Remove the rear cover plate.
3.
Replace the batteries.
Refer to chapter 4.2, page 10, for required battery specifications.
Never use new and used batteries together. Batteries must
always be replaced all at the same time.
4.
Re-install cover plate.
5.
Dispose of batteries according to regulations.
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
31
Operating vacuum pump system
Vacuum Pump System SC 920G
8.2. Operation without hand terminal
The following actions can be taken directly on the vacuum pump
system when the hand terminal is removed (Fig. 15):
1
2
3
4

Stop the process;

Open and close the ventilation valve;

Open and close the high-performance condenser's coolant
valve (accessory).

Call the hand terminal (paging); the hand terminal will answer
with a signal tone.
Stop process button
To open/to close ventilation
valve button
Call the hand terminal
button (paging)
Button to open/to close
coolant valve (accessory)
on the high-performance
condenser
Fig. 15: Buttons on vacuum pump system
8.3. Software
Please see the delivered CD for information on operating the
vacuum pump system via software.
32
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
Vacuum Pump System SC 920G
Servicing
9.
Servicing
9.1. Servicing Schedule
Component
Vacuum pump
system
Diaphragms and
valve plates
Servicing interval
Regular inspection for external damage or
leaks
Replace at the latest, when pump output
decreases
Tab. 5
9.2. Cleaning
When cleaning, make sure that no liquids enter the inside of
the housing.
9.2.1. Flushing Vacuum pump system
Personal injury caused by poisoning or explosion
and damage to the vacuum system
 When flushing the vacuum pump system with
inert gas, make sure that the gas ballast valve is
WARNING
closed so no reactive or explosive mixtures can
form.
Before switching off the vacuum pump system, separate it from the
vacuum chamber and flush it with air (if necessary for safety reasons: with an inert gas) under atmospheric conditions (ambient
pressure) for about five minutes.
If inert gas is used: connect the inert gas feed to the gas inlet (Fig.
2/7, page 11) of the vacuum pump system. Observe the safety
instructions in chapter 3.
9.2.2. Cleaning Vacuum pump system
 Only clean vacuum pump system with a damp cloth and nonflammable cleaning agents.
9.2.3. Emptying collection flask on the suction and pressure
sides
Suction side
1.
Grasp the collection flask (Fig. 2/12, page 11) and simultaneously remove attachment clamp 11; pull out collection flask.
2.
Dispose of contents in collection flask according to local regulations. Then rinse out collection flask.
3.
Reattach collection flask.
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
33
Servicing
Vacuum Pump System SC 920G
Pressure side
34
1.
Grasp the collection flask (Fig. 2/15, page 11) and simultaneously remove attachment clamp 16; pull out collection flask.
2.
Dispose of contents in collection flask according to local regulations. Then rinse out collection flask.
3.
Reattach collection flask.
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
Vacuum Pump System SC 920G
Servicing
9.3. Changing Diaphragms and Valve Plates
Conditions
Tools and material

Vacuum pump system is switched off and mains plug is
removed from the socket

Vacuum pump system is clean and free of hazardous materials
Qty
1
1
1
1
Material
Phillips-head screwdriver No. 2
4-mm hexagon screwdriver
Service Set (see chapter 11, page 45)
Felt-tip pen
Tab. 6
Information on procedure
 Always replace diaphragms and valve plates together to
maintain the pump performance.
Health hazard due to dangerous substances
in the vacuum pump system and pump!
Depending on the substance transferred, caustic
WARNING burns or poisoning are possible.
 Wear protective clothing if necessary, e.g.
protective gloves.
 Flush vacuum pump system before replacing the
diaphragms and valve plates (see chapter 9.2.1,
page 33).
Danger of burns from hot pump parts
The pump head or motor may be hot even after the
pump has been shut off.
CAUTION
 Allow the pump to cool off after operation.
Remove pump head
1. Remove tubing from the inlet and outlet connectors of the
pump.
2. Undo the two screws (Fig. 16/1) and nine screws (2) of the
head cover (3).
3. Undo two screws (6) each, and remove both covers (5) at head
cover (4).
4. Lift the head cover (3) off the pump housing (17).
5. Lift off head plate (9) with intermediate plates (10), (13) and
(14).
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
35
Servicing
Vacuum Pump System SC 920G
Fig. 16: Pump (exploded drawing, symbolic)
Change diaphragms
1.
Turn the diaphragms (15) (2 pieces) and (22) (1 piece)
outwards with your hands, counterclockwise. For this, turn the
fan (19) such that you can easily grip each diaphragm with
your hands.
For diaphragms (15):
Make sure the diaphragm spacers being between diaphragm
and connecting rod (21) do not fall into the pump housing.
If diaphragm spacers should adhere to the diaphragms, take
them off and put them on the thread of the corresponding
connecting rod.
In order to ensure the pneumatic output of the pump, it is
essential that the diaphragm washers are subsequently
remounted in the same quantity in each case.
2. Screw the new diaphragms (15) (2 pieces) and (22) (1 piece)
onto the connecting rods (20) and (21) and tighten it by hand.
Before you finally tighten the diaphragm, you are
recommended to move the diaphragm to the upper dead
center by rotating the fan (19).
3. Put head plate (9) with intermediate plates (10), (13) and (14)
on adapter (16).
36
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
Vacuum Pump System SC 920G
Servicing
Change valve plates
1.
Mark the position of head plate (9) and intermediate plate (10)
relative to each other by a drawing line with a felt-tip pen. This
helps avoid incorrect assembly later.
2.
Mark the position of head plate (9) and intermediate plate (13)
relative to each other by two drawing lines with a felt-tip pen.
3.
Mark the position of head plate (9) and intermediate plate (14)
relative to each other by three drawing lines with a felt-tip pen.
4.
Undo the three screws (6) in head plate (9) and remove head
plate from intermediate plates (10), (13) and (14).
5.
Remove valve plates (12) and O-rings (11) from intermediate
plates (10), (13) and (14).
Instead of lying on intermediate plate, O-rings could stick to
head plate (9).
6.
Lay the new valve plates (12) and the new O-rings (11) on the
intermediate plates (10), (13) and (14).
Upper and lower sides of the valve plates are identical. For
correct position see fig. 17.
Fig. 17: Position of valve plates (12)
7.
Dispose of the old diaphragms and valve plates/sealings
properly.
Mount pump head
1.
Place head plate (9) on intermediate plates (10), (13) and (14)
in the position indicated by the drawing lines.
At the front edge the three intermediate plates must lie in a line
on which head plate is placed flushly.
2.
Fig. 18: Position and orientation of
disk spring (7) and washer (8) at
screw (6)
Tighten the three screws (6) of head plate (9) carefully slightly
hand-tight (tightening torque: 0.6 Nm).
For position and orientation of disk spring (7) and washer (8) of
screw (6) see fig. 18.
3.
Place head cover (3) on pump housing (17).
4.
Tighten the nine screws (2) of head cover (3) slightly in the
first instance. Start with the screws of medium pump stage,
then tighten the screws on the right, and finally on the left.
5.
Now, tighten the screws (2) firmly (tightening torque: 6 Nm);
tighten the center screws first, then continue outward.
If the screws are stiff to turn, the intermediate plates do not lie
in a line at front edge, or intermediate plates and head plate
are not placed flushly (see step 1).
6.
Remount the covers (4).
7.
Tighten the two screws (1) on the head cover (tightening
torque: 5 Nm).
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
37
Servicing
Vacuum Pump System SC 920G
Final steps
38
1.
Reconnect vacuum pump system tubing.
2.
Reconnect vacuum pump system to the electricity supply.
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
Vacuum Pump System SC 920G
Servicing
9.4. Replace overpressure valve on high
performance condenser
Conditions
Information on procedure

Vacuum pump system is switched off and mains plug is
removed from the socket

Vacuum pump system is clean and free of hazardous materials
Health hazard due to dangerous substances
in the vacuum pump system and pump!
Depending on the substance transferred, caustic
WARNING burns or poisoning are possible.
 Wear protective clothing if necessary, e.g.
protective gloves.
 Flush vacuum pump system before replacing
overpressure valve (see chapter 9.2.1, page 33).
1. Unscrew and remove hose nozzle which connects the high
performance condenser with the pressure side of the pump
from high performance condenser.
2. Detach the old overpressure valve from screw socket of high
performance condenser.
3. Slide on the new overpressure valve. Be aware that the
overpressure port is completely covered.
4. Reconnect high performance condenser with pump.
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
39
Troubleshooting
Vacuum Pump System SC 920G
10. Troubleshooting
Extreme danger from electrical shock!
 Disconnect the pump power supply before working
on the pump.
DANGER  Make sure the pump is de-energized and secure.

Vacuum pump system as a whole: see table 7.

Hand terminal: see table 8.

Software operation: see table 9.
Vacuum pump system as a whole
Problem
Cause
Vacuum pump system is
switched on, but the mains
switch does not light up.
Mains cable not plugged in.  Plug the mains cable for the vacuum
pump system into a properly
grounded power socket.
No current in electricity
 Check the electricity supply.
network.
Vacuum pump system
1. Find and eliminate the cause of the
fuses blown.
overload.
Required vacuum not
Leaks in vacuum chamber.
generated even though pump
is running.
O-ring is not sitting
correctly in the slot on the
suction side of the
collection flask.
Leaks in hose connection.
Hexagonal gland (Fig. 2/8,
p. 12) loose.
40
Solution
2.
Replace the mains fuse(s) of the
vacuum pump system:

Push the locking clip on the fuse
drawer down (Fig. 3/4, p. 12) and
pull the drawer out.

Replace the defective fuse(s)
(for fuse specifications see chapter
4.1, page 8; for fuse order numbers
see chapter 11, p. 45).

Push the fuse drawer back in until it
clicks into position.
1.
Run a test by closing the gas inlet
(Fig. 2/7,p. 11). If the pump reaches
the required vacuum, this confirms
the presence of leaks in the vacuum
chamber.
2.
Eliminate leaks in the vacuum
chamber.
 Adjust O-ring.
 Replace if defective (for order
number for O-ring, see chapter 11,
p. 45).
 Check hoses are sitting correctly on
hose nipples.
 Replace any leaky hoses.
 Replace any damaged hose nipples.
 For ordering numbers see chapter
11, page 45.
 Carefully tighten hexagonal gland
with wrench.
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
Vacuum Pump System SC 920G
Troubleshooting
Vacuum pump system as a whole
Problem
Cause
Solution
Leaks in venting valve.
 Temporarily close the ventilation
connection (Fig. 2/6, p. 12). If this
stops the leak, leaks are present in
the venting valve. In this case:
 Flush the venting valve:
1. Close the gas inlet (Fig. 2/7).
Condensation in pump
head.
2.
If necessary for safety reasons:
Connect inert gas to ventilation
connection. Observe the safety
instructions in chapter 3.
3.
Run the vacuum pump system at
100% pump capacity in evacuation
mode.
4.
Re-open the gas inlet.
 If problem persists, contact KNF
Service.
 Dry system with fresh air or, if
necessary for safety reasons, with
an inert gas:
1. Using inert gas: Connect inert gas
source with gas inlet (Fig. 2/7, p. 12)
and start system up in evacuation
mode (100% capacity). Observe the
safety instructions in chapter 3.
2.
Using air: Open gas line (Fig. 2/7, p.
12) to the surrounding environment
and start system up in evacuation
mode (100% capacity).
3.
Close the gas inlet after 30 seconds,
and leave the vacuum pump system
running for 30 seconds under
vacuum.
4.
Repeat this process 3–5 times.
 If this problem occurs frequently,
place the vacuum pump system at a
higher level than the vacuum
chamber.
Gas outlet blocked on high- Risk of bursting of high-performance
performance condenser.
condenser!
 Eliminate blocking of gas outlet.
Worn diaphragms or valve  Replace diaphragms and valve
plates.
plates (chapter 9.3).
Replaced diaphragms and  Check that the correct diaphragm
valve plates.
spacers are placed under the
diaphragms.
 If necessary, carefully tighten the
pump head fixing screws (Fig. 17/2,
p. 36) in diagonally opposite
sequence.
Pump not activated on
Hand terminal or software
 Make connection.
process start-up, in spite of
not connected to vacuum
pressure decrease command. pump system.
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
41
Troubleshooting
Vacuum Pump System SC 920G
Vacuum pump system as a whole
Problem
Noisy pump.
Cause
Solution
Overcurrent protection of
vacuum pump system has
been activated.
 Reset by switching the vacuum
pump system off and back on.
 Check that there is no object
blocking the pump fan (Fig. 17/20, p.
36) and make sure that adequate
supply and removal of cool air is
provided.
 Find and eliminate any other cause
of pump overload.
 Check that hoses are sitting correctly
on hose nipples.
 Replace any leaking hoses.
 Replace any damaged hose nipples.
 Tighten hose nipple at gas outlet
(Fig. 2/17, p. 12).
Leaking hose connection.
Leaks at hose nipple on
high-performance
condenser.
Leaks in overpressure
valve on high-performance
condenser.
 Check overpressure valve is sitting
correctly; replace if necessary. For
ordering number see chapter 11,
page 45.
Tab. 7
Hand terminal
Problem
Cause
Solution
Hand terminal cannot be
removed from vacuum pump
system.
Hand terminal display fails to
light up.
Transport fastener has not
been removed.
 Remove transport fastener (see
chapter 6, p. 17).
The hand terminal display
keeps showing "No connection"; if a button of the touchscreen is actuated a signal
tone sounds.
42
Hand terminal not switched  Switch hand terminal on.
on.
Batteries of hand terminal
 Charge batteries by placing the
have run down.
terminal in the holder provided on
the vacuum pump system, with the
system switched on.
 Alternatively, operate the terminal
via the power supply.
Vacuum pump system is
 Switch the vacuum pump system on
switched off.
at the mains switch. The mains
switch should light up.
The hand terminal is
 Use the page function (see Actuating
designed for use with a
the vaccum pump system, p. 29) to
different SC 920G vacuum
check whether the right hand termipump system.
nal is being used.
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
Vacuum Pump System SC 920G
Troubleshooting
Hand terminal
Problem
Vacuum pump system does
not respond to commands
input at the hand terminal
after removal from the
system, even though the "No
connection " is no longer lit
up and a pressure is
displayed.
Acoustic alarm sounds on
hand terminal.
Marked decrease in operating
time for the hand terminal in
wireless mode.
Vacuum pump system cannot
be activated, even with the
hand terminal placed in the
holder provided.
Pressure display shows
implausible values.
Cause
Solution
Problem with wireless
connection.
 Check whether the hand terminal is
being operated outside the wireless
connection range.
 Check that the wireless connection
is not obstructed by any electrical
devices or metal objects.
 Otherwise, to confirm that the problem lies in the wireless connection,
place the hand terminal in the holder
provided on the vacuum pump
system.
 Contact KNF Service.
 Use the page function (see Actuating
the vaccum pump system, p. 29) to
check whether the right hand terminal is being used.
Defective wireless module.
The hand terminal is
designed for use with a
different SC 920G system,
which is currently in
operation.
Batteries low.
Batteries have reached
limit of their useful life.
 Charge batteries by placing the
terminal in the holder provided on
the vacuum pump system, with the
system switched on.
 Alternatively, operate the terminal
via the power supply.
 Change batteries (see chapter 8.1.3,
p. 31).
Soiled contacts on the
 Clean contacts.
bottom of the hand terminal
or in the holder for the
terminal on the vacuum
pump system.
Unit of pressure for display  Set desired unit of pressure.
has been changed.
Leaks in system.
 See Tab. 8, "Required vacuum not
generated even though pump is
running”.
Recalibration of pressure
 Contact KNF Service.
sensor required.
Tab. 8
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
43
Troubleshooting
Vacuum Pump System SC 920G
Software operation
Problem
Cause
Solution
PC software unable to
connect to vacuum pump
system.
Vacuum pump system not
switched on.
USB connection between
system and PC is not
operating correctly.
 Switch vacuum pump system on.
Pressure display shows
implausible values.
Unit of pressure for display
has been changed.
Leaks in system.
Recalibration of pressure
sensor required.
 Check correct connection of USB
cable. If necessary, pull out the USB
cable and reinsert (USB interface
reset).
 Set desired unit of pressure.
 See Tab. 8, "Required vacuum not
generated even though pump is
running”.
 Contact KNF Service.
Tab. 9
Fault cannot be rectified
If you are unable to determine any of the specified causes, send
the vacuum pump system to KNF Customer Service (see last page
for the address).
1. Flush the vacuum pump system to free the pump head, tubing
and glas vessels of dangerous or aggressive gases (see
chapter 9.2.1, page 33).
2. Clean the vacuum pump system (see chapter 9.2.2, page 33).
3. Send the vacuum pump system, together with completed
Health and Safety Clearance and Decontamination Form
(Chapter 13), to KNF stating the nature of the transferred
medium.
44
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
Vacuum Pump System SC 920G
Ordering Information
11. Ordering Information
Spare parts Pump
Spare part
A spare parts kit SC 920G:
3 diaphragms, 6 valve plates and
6 O-rings (24 x 2)
A spare parts kit SC 920:
3 diaphragms, 6 valve plates, 6 O-rings
(24 x 2) and 2 O-rings (5.5 x 2)
Stabilization diaphragm (only SC 920)
Order-No.
305355
111905
059619
Tab. 10
Other spare parts
Spare part
Overpressure valve for highperformance condenser
Battery set for hand terminal
(see chapter 8.1.3, page 31)
Power supply for hand terminal
USB cable
Mains cable D
Mains cable CH
Mains cable GB
Mains cable USA/JP
Tubes (yard ware)*
Hose nipple gas inlet and pump
connections (ID 10)
Hose nipple ventilating (ID 6)
Hose nipple for high performance
condenser: gas connection (ID 10)
Hose nipple for high performance
condenser: coolant connection (ID 8)
O-ring adapter on collection flask
Collection flask 500 ml (coated)
Flask clamp
Fuse T 2.5
Allen key 2.0 for transport fastener
Tab. 11
Order-No.
047807
117427
302033
136174
026363
027523
029866
027524
028187
112005
055958
026237
025981
047744
047729
025968
027575
117432
* Please specify the required length (in whole meters)
Accessories
Accessory
Coolant valve
Color sticker for indicating correct
match between hand terminal and
vacuum pump system*
Chemical-resistant protective film for
hand terminal display
Order-No.
117121
117433
117407
Tab. 12
* For situations in which several SC 920G vacuum pump systems are
operated within the wireless connection range.
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
45
Returns
Vacuum Pump System SC 920G
12. Returns
Pumps and systems used in laboratories and process-based
industries are exposed to a wide variety of conditions. This means
that the components contacting pumped media could become
contaminated by toxic, radioactive, or otherwise hazardous
substances.
For this reason, customers who send any pumps or systems back
to KNF must submit a Health and safety clearance and
decontamination form in order to avoid a hazardous situation for
KNF employees. This Health and safety clearance and
decontamination form provides the following information, among
other things:

physiological safety

whether medium-contacting parts have been cleaned

whether the equipment has been decontaminated

media that have been pumped or used
To ensure worker safety, work may not be started on pumps or
systems without a signed Health and safety clearance and
decontamination form.
For optimal processing of a return, a copy of this declaration
should be sent in advance via e-mail, regular mail, or fax to KNF
Customer Service (refer to final page for address). In order to avoid
endangering employees who open the shipment's packaging,
despite any residual hazards, the original version of the Health and
safety clearance and decontamination form must accompany the
delivery receipt on the outside of the packing.
The template for the Health and safety clearance and
decontamination form is included with these Operating Instructions
and may also be downloaded from the KNF website.
The customer must specify the device type(s) and serial number(s)
in the Health and safety clearance and decontamination form in
order to provide for the unambiguous assignment of the
Declaration to the device that is sent to KNF.
In addition to the customer's declaration of physiological safety,
information about operating conditions and the customer's
application are also of importance to ensure that the return
shipment is handled appropriately. Therefore, the Health and
safety clearance and decontamination form requests this
information as well.
46
Translation of original Operating Instructions, English, KNF 121308-121311 12/16
Vacuum Pump System SC 920G
Health and safety clearance and decontamination form
13. Health and safety clearance and
decontamination form
Translation of original Operating Instructions, english, KNF 121308-121311 12/16
47
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