KNF LAB SC950 User manual

KNF 125549-125552 11/12
Translation of original Operating Instructions, English
Operating Instructions
Read and observe these Operating Instructions!
Vacuum pump systems
SC950 SEM950 SH950 SR950
KNF Neuberger GmbH
Alter Weg 3
D-79112 Freiburg
Germany
Phone ++49 / (0)7664 / 5909-0
Fax ++49 / (0)7664 / 5909-99
E-Mail: [email protected]
www.knf.de

Translation of original Operating Instructions, English, KNF 125549-125552 11/12
Items including delivery SC950:
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
CD with digital Operating Instructions and software for
operating the vacuum pump system with a PC
Items including delivery SEM/SH/SR950:
Vacuum pump system
Coated collection flasks (2 x)
Flask clamps (2 x)
Mains cable
Operating Instructions
CD with digital Operating Instructions
Transport fastener (only SC950)
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.

Vacuum Pump System SC/SEM/SH/SR950 Content
Translation of original Operating Instructions, English, KNF 125549-125552 11/12
Content Page
1. About this document 4
1.1. Use of the Operating Instructions 4
1.2. Symbols and markings 4
2. Use 5
2.1. Intended use 5
2.2. Improper use 6
3. Safety 7
4. Technical data 9
4.1. Vacuum pump system 9
4.2. Vacuum pump system’s hand
terminal (only SC950) 11
4.3. Software (only SC950) 12
5. Assembly and function 13
5.1. SC590 13
5.1.1. Assembly of the vacuum pump
system 13
5.1.2. Vacuum pump system functions14
5.1.3. Hand terminal 15
5.2. SEM950 17
5.2.1. Assembly of the vacuum pump
system 17
5.2.2. Vacuum pump system functions18
5.3. SH950 19
5.3.1. Assembly of the vacuum pump
system 19
5.3.2. Vacuum pump system functions20
5.4. SR950 21
5.4.1. Assembly of the vacuum pump
system 21
5.4.2. Vacuum pump system functions22
5.5. Pump 23
5.6. Gas ballast 24
6. Installation and connection 25
6.1. Installation 25
6.2. Connection 26
7. Operation 27
7.1. Start up 27
7.2. Taking system out of operation 30
8. Operating vacuum pump system 31
8.1. Hand terminal (only SC950) 31
8.1.1. General functions and displays 31
8.1.2. Operation 33
8.1.3. Changing batteries on the hand
terminal 37
8.2. Operation without hand terminal 38
8.2.1. SC950 38
8.2.2. SEM950 39
8.2.3. SH/SR950 40
8.3. Software 41
8.3.1. General functions and displays 41
8.3.2. Operation 42
9. Servicing 47
9.1. Servicing schedule 47
9.2. Cleaning 47
9.2.1. Flushing vacuum pump system 47
9.2.2. Cleaning vacuum pump system 47
9.2.3. Emptying collection flask on the
suction and pressure sides 47
9.3. Replacing diaphragms and valve
plates 49
9.3.1. Removing the pump 50
9.3.2. Overview of pump parts 51
9.3.3. Disassembling head connection 52
9.3.4. Disassembling pump heads 52
9.3.5. Replacing the diaphragms and
valve plates 54
9.3.6. Assembling heads and head
connection 55
9.3.7. Final steps 56
10. Troubleshooting 57
11. Spare parts and accessories 62
11.1. Spare parts 62
11.2. Accessories 63
12. Decontamination Declaration 64
13. Annex: Interface protocol 65

About this document Vacuum Pump System SC/SEM/SH/SR950
4 Translation of original Operating Instructions, English, KNF 125549-125552 11/12
1. About this document
1.1. Use of 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.
Forward the Operating Instructions to any subsequent owners
of the vacuum pump system.
Customer-specific project systems (systems which begin with “PJ”
or “PM”) may differ from the Operating Instructions.
In case of project systems, take note of any additionally agreed
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
WARNING
A danger warning is located here.
It also indicates the possible consequences of failure
to observe the warning. The signal word (i.e.
“Warning”) indicates the level of danger.
Here you will see actions for avoiding the danger
and potential consequences.
Danger levels
Signal word Meaning Consequences if not observed
warns of
immediate danger
Consequences include death
or serious injuries and/or
serious property damage.
warns of potential
danger
Death or serious injuries
and/or serious property
damage are possible.
warns of a
potentially
dangerous situa-
tion
Minor injuries or damage to
property are possible.
Tab. 1
Other information and symbols
This indicates an activity (step) that must be carried out.
1. This indicates the first step of an activity to be carried out. Any
additional steps are consecutively numbered.
This symbol indicates important information.
Project systems

Vacuum Pump System SC/SEM/SH/SR950 Use
Translation of original Operating Instructions, English, KNF 125549-125552 11/12 5
2. Use
2.1. Intended use
The vacuum pump systems SC/SEM/SH/SR950 are designed for
use in chemical, pharmaceutical, and biological laboratories. They
are exclusively intended for transferring gases and vapors.
Make sure that the installation location is dry and the pump/system
is protected against water in the form of rain, spray, splashes and
drips.
Vacuum pump system is solely for use in indoor areas.
Owner's responsibility
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.
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 trans-
ferred danger-free in the specific application case.
Only transfer gases which remain stable under the pressures and
temperatures occurring in the pump.
Only SC/SEM/SH950:
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 liquid-
connections on the high performance condenser. Inlet and outlet
connections for the gas are not interchangeable.
Laboratory equipment or additional components connected to a
vacuum pump system have to be suitable for use with the pneu-
matic capabilities of the vacuum pump system (see chapter 4,
page 8).
Operating parameters and
conditions
Requirements for
transferred medium
High performance condenser
Accessories

Use Vacuum Pump System SC/SEM/SH/SR950
6 Translation of original Operating Instructions, English, KNF 125549-125552 11/12
2.2. Improper use
The vacuum pump system must 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) or an
open gas ballast 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
pressure simultaneously.
Never apply positive pressure to the suction side of the vacuum
pump system.

Vacuum Pump System SC/SEM/SH/SR950 Safety
Translation of original Operating Instructions, English, KNF 125549-125552 11/12 7
3. Safety
The vacuum pump systems are built according to the generally
recognized rules of technology and in accordance with the
pertinent occupational safety and accident prevention regulations.
Nevertheless, potential dangers during use can result in injuries to
the user or others or in damage to the pump systems or other
property.
Only use the vacuum pump systems when they are in a good
technical and proper working order, in accordance with their
intended use, observing the safety advice within the Operating
Instructions, at all times.
Make sure that only trained and instructed personnel or specially
trained personnel work on the vacuum pump systems. This
especially applies to assembly, connection and servicing work.
Make sure that all personnel have read and understood the Opera-
ting Instructions, especially the "Safety" chapter.
Observe the accident prevention and safety regulations when per-
forming any work on the vacuum pump systems and during opera-
tion.
Do not expose any part of your body to the vacuum.
Open housing parts with notice sticker (see fig. 1) only after sepa-
rating mains plug from power source.
Only SC950:
Ensure that personnel check that the hand terminal is the right one
for this particular system before using a SC950 vacuum pump
system. Vacuum pump systems are equipped with a paging sys-
tem for this purpose (see Actuating the vacuum pump system,
page 36).
When transferring dangerous media, observe the safety regula-
tions for handling such media.
Be aware that the vacuum pump systems are not designed to be
explosion-proof.
Make sure the temperature of the medium is always sufficiently
below its ignition temperature, to avoid ignition or explosion. This
also applies to 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 maximum permissible operating pressure of the
vacuum pump system. The maximum permissible operating pres-
sure of the vacuum pump system is stated in the technical speci-
fications (see chapter 4, page 9).
If necessary, consider any external sources of energy, such as
sources of radiation, that could additionally heat the medium.
Personnel
Working in a safety-
conscious manner
Fig. 1: Notice sticker
Correct match between hand
terminal and vacuum pump
system
Handling dangerous media
Handling flammable media

Safety Vacuum Pump System SC/SEM/SH/SR950
8 Translation of original Operating Instructions, English, KNF 125549-125552 11/12
In case of doubt, consult the KNF customer service.
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. 2/18, p. 13 (SC950) or Fig. 4/15, p. 17 (SEM950))
is 0.1 bar g.
All replacement parts should be properly stored and disposed of in
accordance with the applicable environmental protection
regulations. Ensure adherence to the pertinent national and
international regulations. This applies especially to parts
contaminated with toxic substances.
The vacuum pump systems SC/SEM/SH/SR950 conform to the
Directive 2011/65/EU (RoHS2).
The vacuum pump systems SC/SEM/SH/SR950 conform to the
safety regulations of the EC Directive 2004/108/EC concerning
Electromagnetic Compatibility and the EC Directive 2006/42/EC
concerning Machinery. The requirements of the following
harmonised standards have been used:
DIN EN 61010-1
DIN EN 61326-1
The systems correspond to IEC 664:
the overvoltage category II
the pollution degree 2
All repairs to the vacuum pump system must be carried out by the
relevant KNF Customer Service team.
Housings with voltage-caring parts may be opened by technical
personnel only.
Use only genuine parts from KNF for servicing work.
Ventilating the vacuum pump
system
Environmental protection
Standards
Customer service and
repairs

Vacuum Pump System SC/SEM/SH/SR950 Technical data
Translation of original Operating Instructions, English, KNF 125549-125552 11/12 9
4. Technical data
4.1. Vacuum pump system
Materials for parts contacting the medium*
Pump head PPS
Connection parts PPS
Diaphragms PTFE-coated
Valve plates FFPM
Flat seals FFPM
O-rings, green FPM
O-rings, black FFPM
Hose connector gas inlet PTFE / PVDF
Jose connector gas outlet PP / PVDF
Hose connector inert gas
connection
POM / PA
Tubing Norprene®
Only SC/SEM950:
Tubing inert gas connection
PVC
Adaptor separator PP
Only SC/SEM950:
Pressure sensor Ceramics / 1.4404
Venting valve / Gas ballast
valve:
Piston seal
O-ring
Tube
FFPM
FPM
1.4301
Pneumatic performance
Max. permissible operating
pressure [bar g]
0
Ultimate vacuum [mbar abs.] ≤2 mbar
≤4 mbar with opened gas ballast
Flow rate at atm. pressure
[l/min]**
50 (controllable)
Max. permissible pressure at
the inert gas connection [bar g]
0.1
Ambient and media temperature
Permissible
ambient temperature
+ 10 °C to + 40 °C
Permissible media temperature + 10 °C to + 40 °C
*according to DIN ISO 1629 and 1043.1
**Liters in standard state (1,013 mbar at 0 °C)
Tab. 2 (part 1)

Technical data Vacuum Pump System SC/SEM/SH/SR950
10 Translation of original Operating Instructions, English, KNF 125549-125552 11/12
Other parameters
Vacuum connection and gas
outlet
For tube ID 10 mm
Ventilation connection For tube ID 4 mm
Weight [kg]:
- SC950 (including hand
terminal)
- SEM950
- SH950
- SR950
14
13.5
13
12.5
Dimensions W x H x D [mm]:
SC/SEM/SH950:
SR950:
246 x 487 x 313
246 x 487 x 264
Maximum permissible ambient
relative humidity
80 % for temperatures up to
31°C, decreasing linearly to
50 % at 40°C
Maximum altitude of
installation
[m above sea level]
2000
Only SC/SEM/SH950:
Operating parameters of coolant (high-performance condenser)
Max. permissible pressure
[bar g]
3
Permissible temperature - 15 °C to + 20 °C
Coolant connections on high-
performance condenser
For tube ID 8 mm
Coolant-wetted surface [cm2] Min. 470
Electrical data vacuum pump system
Voltage*** [V] 100-240 V +/- 10 %
Frequency [Hz] 50-60 Hz
Max. current consumption [A] 1.7
Max. watt consumption [W] 150
Protection class IP20
Fuse vacuum pump system [A] 2 x T2.5
Drive motor fusing Electronic overcurrent protection
Tab. 2 (part 2) *** Automatic voltage selection
The pumps of the vacuum pump systems are supplied by a
universal power supply with integrated overload protection.
They are protected against overheating by a temperature
sensor on the motor board and equipped with overcurrent
protection.
If one of these safety functions is triggered, the pump will be
shut down and must be manually reset, as follows:
Separate pump from the mains.
Remove the cause(s) of the fault before restarting.

Vacuum Pump System SC/SEM/SH/SR950 Technical data
Translation of original Operating Instructions, English, KNF 125549-125552 11/12 11
4.2. Vacuum pump system’s hand terminal (only
SC950)
Dimensions: W x H x D [mm] 91 x 190 x 65
Weight [kg] 0.5
Operating voltage [V DC] 12
Current consumption [A] 1.25
Wireless connection's
frequency band [GHz]
2.4
Wireless range About 50 m without obstacles,
about 10 m through walls
Power supply Through integrated batteries or
power supply (in delivery
included)
DC charging socket
External diameter: 6.3 mm
Inside diameter: 2 mm
Chargeable batteries 4 x round AA 1.2 V 2300 mAh,
fast-charging; see spare parts
list in chapter 11
Battery service life* Up to 12 hours, depending on
number of entries and data
transmission
Charging time* approx. 7 h
Tab. 3 * Applies to standard included batteries
When charging the SC950 vacuum pump system's hand
terminal, use only the original power supply from KNF.
Several different vacuum pump systems SC590 may be
operated simultaneously with their respective hand terminals
within the wireless connection range.
The wireless connection between hand terminal and vacuum
pump system SC590 is robustly resistant to operation of
mobile telephones and Bluetooth devices in the immediate
area.

Technical data Vacuum Pump System SC/SEM/SH/SR950
12 Translation of original Operating Instructions, English, KNF 125549-125552 11/12
4.3. Software (only SC950)
System requirements for operating the vacuum pump system
SC950 via PC software:
Windows 98 SE, Windows ME, Windows NT, Windows 2000,
Windows XP, Windows Vista, Windows 7
200 MHz processor
Available memory of at least 64 MB
The USB connection between the PC and vacuum pump system
SC950 is operated as an RS-232 interface. Accordingly, in the
operating system it is managed as an additional COM connection
and can be addressed with conventional terminal software. The
interface protocol contains all necessary information. See chapter
13, page 65.

Vacuum Pump System SC/SEM/SH/SR950 Assembly and function
Translation of original Operating Instructions, English, KNF 125549-125552 11/12 13
5. Assembly and function
5.1. SC590
5.1.1. Assembly of the vacuum pump system
1Carrying handle
2Transport fastener for hand
terminal
3High-performance
condenser
4Hand terminal
(removable; signals
transmitted wirelessly)
5Hand terminal dock
6 Gas ballast switch
7Flask clamp for 8and 9
8 Pressure-side condensa-
tion collection flask (coated)
9Suction-side condensation
collection flask (coated)
10 Base
11 Mains switch
12 Top fan
13 Bottom fan
14 Coolant valve connection
15 USB port for connecting
vacuum pump system to
PC
16 Mains plug connection
17 Fuse drawer
18 Ventilation connection
19 Vacuum chamber
connection (gas inlet)
20 Coolant connection on
high-performance
condenser (feed)
21 Coolant connection on
high-performance
condenser (return)
22 Gas outlet
Fig. 2: Vacuum pump system SC950

Assembly and function Vacuum Pump System SC/SEM/SH/SR950
14 Translation of original Operating Instructions, English, KNF 125549-125552 11/12
The vacuum pump system generates a vacuum that can be con-
trolled either through the hand terminal (see Fig. 2/4, p. 13) or a
PC.
Collection flask (Fig. 2/9) 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 (7).
The high-performance condenser (3) 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 con-
denser is surrounded by a shell for temperature insulation and
explosion protection.
Solvents deposited in the high-performance condenser are col-
lected in the coated (for explosion protection) collection flask (8). A
flask clip (7) secures the glass flask to the condenser flange. A
recirculating cooler or continuously flowing cold water (or another
cooling media) cools the high-performance condenser to the
condensation temperature.
5.1.2. 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 set-
point 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. 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
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 con-
trol, 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 pur-
poses of intelligent process control. For example, after successful

Vacuum Pump System SC/SEM/SH/SR950 Assembly and function
Translation of original Operating Instructions, English, KNF 125549-125552 11/12 15
boiling point detection in the automatic mode, the following opera--
ting 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)
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.
The gas ballast switch (Fig. 2/6) can be used to open and close the
gas ballast valve on the vacuum pump system's pump (see
Chapter 5.6).
5.1.3. Hand terminal
Basic elements
1 Upper grip
2Touchscreen
3I/O switch
4 DC input 12 V
5Rotary knob for
adjusting pump speed
and setpoint pressure
switching to manual
operation
Fig. 3: Hand terminal SC950
Function
The hand terminal is used to set process parameters with which
the vacuum pump system SC950 will control pressure.
Settings can be made on the hand terminal's touchscreen (2) and
with the rotary knob (5).
To operate the vacuum pump system remotely, remove the hand
terminal from the holder (see chapter 5.1.1, page 13) 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.
Gas ballast

Assembly and function Vacuum Pump System SC/SEM/SH/SR950
16 Translation of original Operating Instructions, English, KNF 125549-125552 11/12
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 termi-
nal with electrical power directly from a mains connection.
An acoustic alarm sounds on the hand terminal when the battery
charge levels are low.

Vacuum Pump System SC/SEM/SH/SR950 Assembly and function
Translation of original Operating Instructions, English, KNF 125549-125552 11/12 17
5.2. SEM950
5.2.1. Assembly of the vacuum pump system
1Carrying handle
2High-performance
condenser
3Control terminal
4 Gas ballast switch
5Flask clamp for 6and 7
6 Pressure-side condensa-
tion collection flask (coated)
7Suction-side condensation
collection flask (coated)
8Base
9Mains switch
10 Top fan
11 Bottom fan
12 Coolant valve connection
13 Mains plug connection
14 Fuse drawer
15 Ventilation connection
16 Vacuum chamber
connection (gas inlet)
17 Coolant connection on
high-performance
condenser (feed)
18 Coolant connection on
high-performance
condenser (return)
19 Gas outlet
Fig. 4: Vacuum pump system SEM950

Assembly and function Vacuum Pump System SC/SEM/SH/SR950
18 Translation of original Operating Instructions, English, KNF 125549-125552 11/12
Collection flask (Fig. 4/7) 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 (5).
The high-performance condenser (2) 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 con-
denser is surrounded by a shell for temperature insulation and
explosion protection.
Solvents deposited in the high-performance condenser are col-
lected in the coated (for explosion protection) collection flask (6). A
flask clip (5) secures the glass flask to the condenser flange. A
recirculating cooler or continuously flowing cold water (or another
cooling media) cools the high-performance condenser to the
condensation temperature.
5.2.2. Vacuum pump system functions
The flow of the pump (15% - 100%) can be set via the rotary knob
on the control terminal (3).
The gas ballast switch (4) can be used to open and close the gas
ballast valve on the vacuum pump system's pump (see Chapter
5.6).
Gas ballast

Vacuum Pump System SC/SEM/SH/SR950 Assembly and function
Translation of original Operating Instructions, English, KNF 125549-125552 11/12 19
5.3. SH950
5.3.1. Assembly of the vacuum pump system
1Carrying handle
2High-performance
condenser
3Rotary knob
4 Gas ballast switch
5Flask clamp for 6and 7
6 Pressure-side condensa-
tion collection flask (coated)
7Suction-side condensation
collection flask (coated)
8Base
9Mains switch
10 Top fan
11 Bottom fan
12 Mains plug connection
13 Fuse drawer
14 Vacuum chamber
connection (gas inlet)
15 Coolant connection on
high-performance
condenser (feed)
17 Coolant connection on
high-performance
condenser (return)
17 Gas outlet
Fig. 5: Vacuum pump system SH950

Assembly and function Vacuum Pump System SC/SEM/SH/SR950
20 Translation of original Operating Instructions, English, KNF 125549-125552 11/12
Collection flask (Fig. 5/7) 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 (5).
The high-performance condenser (2) 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 con-
denser is surrounded by a shell for temperature insulation and
explosion protection.
Solvents deposited in the high-performance condenser are col-
lected in the coated (for explosion protection) collection flask (6). A
flask clip (5) secures the glass flask to the condenser flange. A
recirculating cooler or continuously flowing cold water (or another
cooling media) cools the high-performance condenser to the
condensation temperature.
5.3.2. Vacuum pump system functions
The flow of the pump can be set via the rotary knob on the control
terminal (3).
I If the rotary knob is rotated to the left until it engages the
mechanical indent, the pump will rotate with a minimum flow
rate of 15%.
If the rotary knob is then rotated farther to the left (past the
mechanical indent), the vacuum pump system's pump will be
switched off.
The gas ballast switch (4) can be used to open and close the gas
ballast valve on the vacuum pump system's pump (see Chapter
5.6).
Gas ballast