BSH HN678G4S1 Setup guide

Repair Instructions – Cooking
2016-03-10 / DIS 184_58300000140186_ara_en_k Copyright by BSH Hausgeräte GmbH Page 1 of 181
1 Concerning this document 4
1.1 Important information......................................................................................4
1.2 Explanation of symbols...................................................................................4
2 Safety 6
2.1 Qualification.................................................................................................... 6
2.2 General safety information............................................................................. 6
2.3 Product-specific safety information.................................................................7
2.4 Measures after each repair............................................................................ 8
3 Design and function 9
3.1 Baking sensor (Lambda sensor).................................................................... 9
3.2 Meat temperature probe (NTC)....................................................................13
3.3 Brushless direct current motor..................................................................... 14
3.4 Steam generation......................................................................................... 17
3.5 Steam generator........................................................................................... 18
3.6 Double pump................................................................................................ 20
3.7 EcoClean Direct............................................................................................21
3.8 Suitability of cookware..................................................................................22
3.9 Cooking compartment temperature sensor (Pt500 / Pt1000)....................... 25
3.10 Fold-down door.............................................................................................26
3.11 Magnetron..................................................................................................... 27
3.12 Swivelling panel............................................................................................ 29
3.13 Temperature regulation in the various operating modes.............................. 30
3.14 Temperature regulation in the various operating modes.............................. 35
3.15 Vapour extraction system............................................................................. 40
4 Fault diagnosis 43
4.1 Result faults................................................................................................ 43
Food is not cooked.......................................................................................43
Food is heated too slowly............................................................................ 43
Cleaning action is inadequate...................................................................... 43
Pieces of dough form a skin........................................................................ 43
Food dries out.............................................................................................. 44
4.2 Malfunctions................................................................................................ 45
Rails - Sloping down at the back/askew...................................................... 45
Rails - Flashovers/discoloured marks.......................................................... 45
Rails - Flashovers between rail and enamelled baking tray......................... 45
Rails - Jam/become caught..........................................................................46
Rails - Uneven running after pyrolysis......................................................... 46
Baking tray/universal pan warped, bent, bounces ...................................... 46
Operating ring can be rotated easily / no change on the display................. 46
Operating ring does not respond / no display.............................................. 47
Operating ring is hard to turn / remains stuck in a specific position............. 47
Operation is not interrupted when the door is opened................................. 47
Display background white/display hard to read............................................47
Fault code is displayed.................................................................................47
Appliance does not generate any steam......................................................48
Appliance continues to heat although the setpoint temperature has been
attained......................................................................................................... 48
Brightness of microwave differs from that of the oven................................. 48
No microwave output / 8A fuse was blown.................................................. 49
Folding panel only opens partially................................................................49
Folding panel opens at an angle..................................................................49
Folding panel does not close automatically................................................. 49
Cooling fan overruns for too long.................................................................49
NeffLight in the "slide and hide" door flashes briefly.................................... 50
Reset during operation in main menu "MyProfile"........................................50
Door (fold-down door) opens during operation (only microwave
appliances)....................................................................................................50
Door (fold-down door) cannot be closed (only microwave appliances)........ 50
Door (fold-down door) does not open 90°....................................................51
Door (fold-down door) closing is displayed (only microwave appliances).....51
Clock gains > 1 minute every day................................................................51
Time - ist fast / slow..................................................................................... 51
Water escapes into the cooking compartment via the steam inlet................52
Remove water tank is displayed when the pyrolytic self-clean system is
started........................................................................................................... 52
Fill water tank is displayed although the tank is still full............................... 52
Increased water consumption when operating in “steaming” mode............. 53
4.3 Noise............................................................................................................ 54
Rails squeaking............................................................................................ 54
High-frequency whistling sound....................................................................54
Cooling fan motor makes a high-frequency noise........................................54

Repair Instructions – Cooking
2016-03-10 / DIS 184_58300000140186_ara_en_k Copyright by BSH Hausgeräte GmbH Page 2 of 181
Cooling fan motor whistles at a high frequency at certain speeds............... 54
Cooling fan overrun too loud........................................................................54
4.4 Other faults (surface defects, cracks, breaks)........................................ 56
Rails discoloured after pyrolysis...................................................................56
Baking tray/universal pan do not fit on the rails........................................... 56
Control panel and/or door askew................................................................. 56
Difference in display colour/brightness.........................................................56
Difference in colour of microwave/oven turning handle................................56
Gap between panel and door varies............................................................ 57
Connecting sleeve of the cooking compartment seal is becoming frayed
...................................................................................................................... 57
4.5 Leaks............................................................................................................ 58
Steam escapes in the top right-hand corner................................................ 58
Water drips onto the floor/furniture (when the door is opened).................... 59
Vapour/condensation escapes......................................................................59
5 Test 60
5.1 Measure the distance between the front glass panel and the cabinet
cavity............................................................................................................. 60
5.2 Checking the alignment of the panel with the door...................................... 61
5.3 Checking the cooking sensor (Lambda sensor)...........................................63
5.4 Check the ventilation of the appliance in the furniture................................. 64
5.5 Check the meat temperature probe (NTC)...................................................66
5.6 Checking the lighting in the cooking compartment.......................................69
5.7 Check the cooking compartment temperature sensor (PT1000).................. 71
5.8 Check the cooking compartment temperature sensor (PT500)....................74
5.9 Checking condensation................................................................................ 77
5.10 Magnetron prüfen......................................................................................... 79
5.11 Measuring microwave output power.............................................................81
5.12 Checking that the cookware is suitable for microwave use..........................82
5.13 Neo-Inverter prüfen.......................................................................................83
5.14 Checking the position of the wall socket......................................................86
5.15 Checking the socket of the meat temperature sensor..................................87
5.16 Measuring the temperature of the operating surfaces for hot air at
220 °C........................................................................................................... 88
5.17 Measuring the temperature of the operating surfaces for pyrolysis level
3.................................................................................................................... 90
5.18 Measuring the temperature of the operating surfaces for grilling level 3...... 92
5.19 Measuring the temperature of the appliance surfaces for hot air at
200 °C........................................................................................................... 94
5.20 Measuring the temperature of the appliance surfaces for pyrolysis level
3.................................................................................................................... 97
5.21 Measuring the temperature of the furniture surfaces for hot air at
220 °C......................................................................................................... 100
5.22 Measuring the temperature of the furniture surfaces for pyrolysis with level
3.................................................................................................................. 102
5.23 Measuring the temperature in the cooking compartment for hot air at
200 °C......................................................................................................... 104
5.24 Measuring the temperature in the cooking compartment for pyrolysis level
1.................................................................................................................. 106
5.25 Check the heat-resistance of the fitted units..............................................108
5.26 Checking the vapour system......................................................................109
6 Repairs 111
6.1 Remove the Lambda sensor on the Lambda module................................ 111
6.2 Removing and installing the baking sensor module (Lambda module)...... 112
6.3 Removing and installing the fascia (swivelling panel)................................ 113
6.4 Installing and removing the control panel...................................................114
6.5 Removing and installing the control power module....................................115
6.6 Removing and installing the steam generator............................................116
6.7 Removing and installing the steam generator............................................117
6.8 Flashing and coding................................................................................... 118
6.9 Removing and installing the interior light (roof)..........................................120
6.10 Install and remove cabinet upper section...................................................121
6.11 Installing and removing the cabinet back panel......................................... 122
6.12 Installing and removing the cabinet side panel (left).................................. 123
6.13 Installing and removing the cabinet side panel (right)................................124
6.14 Remove and install the appliance.............................................................. 125
6.15 Removing and installing the hot-air fan......................................................126

Repair Instructions – Cooking
2016-03-10 / DIS 184_58300000140186_ara_en_k Copyright by BSH Hausgeräte GmbH Page 3 of 181
6.16 Removing and installing interior and intermediate glass panels and
reflectors..................................................................................................... 128
6.17 Adjusting the fold-down door......................................................................131
6.18 Adjusting the fold-down door safety switch................................................ 139
6.19 Dismantling and assembling the fold-down door........................................145
6.20 Dismantling and assembling the fold-down door........................................148
6.21 Removing and installing the contact spring of the NeffLight...................... 152
6.22 Removing and installing the cooling fan motor.......................................... 154
6.23 Removing and installing the bearing of the guiding rod............................. 155
6.24 Removing and installing the power module............................................... 157
6.25 Removing and installing the magnetron..................................................... 158
6.26 Removing and installing the NEO inverter................................................. 159
6.27 Remove and connect the mains cable.......................................................161
6.28 Removing and installing the deflector........................................................ 162
6.29 Removing and installing the PT500........................................................... 163
6.30 Schwenkblende aus- und einbauen........................................................... 164
6.31 Removing and installing the slide+hide door..............................................166
6.32 Removing and installing the meat temperature probe socket.................... 168
6.33 Removing and installing the door’s guide bushing.....................................169
6.34 Removing and installing the door’s left-hand or right-hand plastic guide... 171
6.35 Emergency unlock the door....................................................................... 173
6.36 Removing and installing the door hinge..................................................... 174
6.37 Removing and installing the door hinge..................................................... 176
6.38 Removing and installing the door hinge..................................................... 177
6.39 Removing and installing the door’s swivel handle......................................178
6.40 Removing and installing the vapour valve..................................................180
6.41 Removing and installing the vapour valve motor....................................... 181

Concerning this document
2016-03-10 / DIS 184_58300000140186_ara_en_k Copyright by BSH Hausgeräte GmbH Page 4 of 181
1.1 Important information
Read and observe chapter 2 "Safety" before performing any work!
1.1.1 Purpose
These repair instructions form the basis for a systematic and safety conscious
procedure for the repair of domestic appliances.
These repair instructions include information about troubleshooting and repair.
1.1.2 Target group
These repair instructions are intended for persons who are familiar with equipment
technology and were instructed by BSH or an authorised body:
• Service technicians for the repair of domestic appliances
• Pre-assemblers in the spare part stockroom when determining required spare
parts
• Call centre employees during order acceptance
1.1.3 Other applicable documents
The following documents include additional relevant repair information:
• General repair instructions
• Error codes and service programs
• Circuit diagrams
• Exploded drawings
• Parts lists
• Repair videos
1.2 Explanation of symbols
1.2.1 Danger levels
The warning levels consist of a symbol and a signal word. The signal word
indicates the severity of the danger.
Warning level Meaning
Non-observance of the warning message will result in death or
serious injuries.
Non-observance of the warning message could result in death
or serious injuries.
Non-observance of the warning message could result in minor
injuries.
Non-observance of the warning message could result in dam-
age to property.
Table 1: Danger levels
1.2.2 Hazard symbols
Hazard symbols are symbolic representations which give an indication of the kind
of danger.
The following hazard symbols are used in this document:
Hazard symbol Meaning
General warning message
Danger from electrical voltage
Risk of explosion

Concerning this document
2016-03-10 / DIS 184_58300000140186_ara_en_k Copyright by BSH Hausgeräte GmbH Page 5 of 181
Hazard symbol Meaning
Danger of cuts
Danger of crushing
Danger from hot surfaces
Danger from strong magnetic field
Danger from non-ionizing radiation
Table 2: Hazard symbols
1.2.3 Structure of the warnings
Warnings in this document have a standardised appearance and a standardised
structure.
Type and source of danger!
Consequences of ignoring the warning.
► Actions to protect from danger.
The following example shows a warning that warns against electric shock due to
live parts. The measure for avoiding the danger is mentioned.
Risk of electric shock due to live parts!
► Disconnect the appliance from the mains at least 60 seconds
before starting the work .
1.2.4 General symbols
The following general symbols are used in this document:
Gen. symbol Meaning
Identification of a special tip (text and/or graphic)
Identification of a key or button
Identification of a material number
Identification of a condition (if ..., then ...)
Identification of a simple tip (only text)
Table 3: General symbols

Safety
2016-03-10 / DIS 184_58300000140186_ara_en_k Copyright by BSH Hausgeräte GmbH Page 6 of 181
2.1 Qualification
In Germany, only qualified electricians trained by BSH or an authorised body may
perform any repair work.
In other countries, only similarly trained qualified personnel is permitted to perform
the repair work.
Appliances must only be repaired by persons that are qualified, approved and
trained by BSH or an authorised body as instructed.
2.2 General safety information
2.2.1 All domestic appliances
Risk of electric shock due to live parts!
• Disconnect the appliance from the mains for at least 60 seconds before starting
work.
• Do not touch the housing, components and cables.
• For tests on an energised system, use a residual current circuit breaker.
• Discharge high-voltage capacitors.
Risk of injury from sharp edges!
• Wear protective gloves.
Risk of injury when dealing with harmful substances!
• Observe the associated safety data sheet!
Risk to the appliance's safety / function!
• Only use original spare parts.
Risk of damage to electrostatically sensitive components (ESDs)!
• Before touching ESDs, use an electrostatic protection system (wristband with
earth safe plug).
• Do not touch connections and conductor paths of the modules.
• Only transport ESDs in conductive materials or original packaging.
• Keep ESDs clear of electrostatically chargeable materials (i.e. plastic).

Safety
2016-03-10 / DIS 184_58300000140186_ara_en_k Copyright by BSH Hausgeräte GmbH Page 7 of 181
2.3 Product-specific safety information
2.3.1 Microwave ovens
Risk of scalding due to explosive escape of liquids in case of delayed
boiling!
• Before heating place a metal spoon in the liquid.
Health hazard due to non-ionising radiation!
• After any work on the appliance, check the tightness with leak rate
measurement.
2.3.2 Induction appliances
Induction appliances fulfil the relevant regulations for safety and electromagnetic
compatibility (EN 50366).
Danger to life due to magnetic fields!
• People with pacemakers should stay clear during repairs on an open
appliance!
Health hazard due to magnetic fields!
• People with medical devices (for example insulin pump / hearing aid) should
stay clear of the opened appliance!
2.3.3 Gas appliances
Explosion hazard due to escaping gas!
• Cut off the gas supply before working on gas carrying connections.
• Check tightness following work on connections carrying gas.
• Only repair gas appliances with original parts that were tested and released for
such use.
If you smell gas!
• Do not press any electrical switches.
• Extinguish / keep clear of open flames.
• Ensure that room is well ventilated.
• Close the gas isolating equipment.
2.3.4 Refrigerators and freezers
Risk of burns caused by refrigerants!
• Wear protective gloves and goggles.
Explosion hazard due to refrigerants!
• Do not solder pipe connections, only use Lokring connections.
• Do not press any electrical switches.
• Keep clear of thermal appliances.
• Extinguish / keep clear of open flames.
• Ensure that room is well ventilated.
2.3.5 Dryer with heat pump
Risk of burns caused by refrigerants!
• Wear protective gloves and goggles.
Explosion hazard due to refrigerants!
• Do not solder pipe connections, only use Lokring connections.
• Do not press any electrical switches.
• Keep clear of thermal appliances.
• Extinguish / keep clear of open flames.
• Ensure that room is well ventilated.

Safety
2016-03-10 / DIS 184_58300000140186_ara_en_k Copyright by BSH Hausgeräte GmbH Page 8 of 181
2.4 Measures after each repair
If the appliance is functional:
• Check according to VDE 0701 or country-specific regulations.
• Check external appearance, function and tightness.
• Document repair work, measured values and functional reliability.
If the appliance is not functional:
• Identify the appliance as “not functionally reliable”.
• Warn customers of commissioning and notify them in writing .

Design and function
2016-03-10 / DIS 184_58300000140186_ara_en_k Copyright by BSH Hausgeräte GmbH Page 9 of 181
3.1 Baking sensor (Lambda sensor)
3.1.1 Structure
Fig. 1: Construction of the baking sensor
1 Protective tube 3 Seal
2 Sensor element 4 Contacts
The sensor element consists of zirconium dioxide ZrO2. It is surrounded by the
protective tube. The protective tube allows the heated sensor element to be
operated at the required operating temperature and prevents mechanical damage.
The air of the cooking compartment reaches the sensor element through holes in
the protective tube.
The sensor element is composed of several layers in planar technology. The
sensor heating is also integrated in these layers.
Fig. 2: Position of the baking sensor in the cooking compartment.
1 Baking sensor
The baking sensor is installed in the ceiling of the cooking compartment (rear right).

Design and function
2016-03-10 / DIS 184_58300000140186_ara_en_k Copyright by BSH Hausgeräte GmbH Page 10 of 181
3.1.2 Function
Fig. 3: Components of the earth's atmosphere
1 Ar - argon 3 O2 - oxygen
2 CO2 - carbon dioxide 4 N2 - nitrogen
The portion of oxygen in the earth's atmosphere (air) is about 21 %.
The baking sensor senses the oxygen content of the air in the cooking
compartment.
Because the content of the oxygen and the humidity of the air are directly related to
each other, the baking sensor also senses the humidity of the air indirectly.
Fig. 4: Relationship of oxygen to humidity
1 O2 - oxygen 2 Humidity
The humidity in the cooking compartment provides information on the progress of
the cooking process.
During cooking, water vapour escapes from the food and increases the humidity
in the cooking compartment. At the same time, the oxygen content of the air in the
cooking compartment is reduced.

Design and function
2016-03-10 / DIS 184_58300000140186_ara_en_k Copyright by BSH Hausgeräte GmbH Page 11 of 181
Fig. 5: Oxygen - humidity concentration
1 Oxygen concentration 2 Humidity concentration
When the oxygen content is at its lowest, the humidity in the cooking compartment
is at its highest.
The cooking process is complete at this point. After a short post-baking time, the
cooking process can be finished (red line) and the food can be removed from the
cooking compartment.
3.1.3 Cooking with the baking sensor
• The operating mode works only for cooking on one level.
Several baking trays would divide the cooking compartment
into different areas and the humidity would no longer be
distributed evenly.
• The door must not be opened during the cooking process. The
inflow of fresh air would distort the measurement of the oxygen
content, and thus of the humidity.
In the "Cooking with the baking sensor" mode, no weights, quantities or cooking
times have to be entered. Thanks to the baking sensor, the electronics can control
the processes in the cooking compartment accurately. A „toothpick test" is no
longer required.
Fig. 6: Humidity/time curve for types of baking and post-baking time
1 Six sponge cakes - 32 minutes 4 Ring cake - 67 minutes
2 Plaited loaf - 34 minutes 5 Cheesecake - 78 minutes
3 Linzer torte - 44 minutes

Design and function
2016-03-10 / DIS 184_58300000140186_ara_en_k Copyright by BSH Hausgeräte GmbH Page 12 of 181
3.1.4 Calibrating the baking sensor
A new backing sensor electronic unit (Lambda module) that has not yet been
calibrated is synchronized automatically with the baking sensor (Lambda sensor)
that is connected.
For new appliances, this is done during the final test at the factory.
If the baking sensor module is replaced as part of a repair, automatic
synchronization between the baking sensor module and the baking sensor will be
performed the first time the mains voltage is applied.
If only the baking sensor was replaced as part of a repair, manual synchronization
between the baking sensor module and the baking sensor must be performed in
the service program.
The manual calibration is started in the (Lambda sensor calibration) service
program.
Here the (Ipump) flow of the baking sensor is sensed and stored. During operation,
this initial value is compared with the current Ipump flow. The result is displayed in
% as (Probe service) in the (Lambda sensor test) service program.
Each calibration causes the previous (Probe service) value to be
deleted.
Recalibration of an old sensor will again produce a (Probe service)
value of 100 %.
Recalibration does not improve the accuracy of the measurement!
Information on the accuracy of the measurement is possible by the level of the
baking sensor current.
See also the chapter "Testing the baking sensor (Lambda sensor)".

Design and function
2016-03-10 / DIS 184_58300000140186_ara_en_k Copyright by BSH Hausgeräte GmbH Page 13 of 181
3.2 Meat temperature probe (NTC)
The meat temperature probe measures the temperature inside the meat (core
temperature) during the cooking process.
When the core temperature reaches the target value (for example 85 °C) the
electronics stops the cooking process.
The plug of the meat temperature probe is inserted in a connector socket on the
left side of the cooking compartment.
The values measured by the meat temperature probe are evaluated by the control
electronics.
In the meat temperature probe, one or more NTC resistors are used as
temperature sensors.
Different meat temperature probes are used to measure the cooking temperature:
•Single-point meat temperature probe (with one NTC resistor)
•Multipoint meat temperature probe (with three NTC resistors)
Depending on their features, the appliances have two- or three-pole connector
sockets for the meat temperature probe.
Two-pole connector sock-
et
Three-pole connector
socket
Single-point meat tem-
perature probe Yes Yes
Multipoint meat tempera-
ture probe No Yes
Table 4: Possible use of the meat temperature probes
In the multipoint meat temperature probe, the position of the
integrated resistors is marked by rings on the tip of the sensor.
If the meat temperature probe is positioned poorly in the meat, the
multipoint meat temperature probe will measure more accurately
than a single-point meat temperature probe.
3.2.1 Single-point meat temperature sensor
Fig. 7: Construction of the single-point meat temperature sensor
1 NTC sensor connector 4 NTC sensor
3 NTC sensor connector
3.2.2 Multipoint meat temperature probe
Fig. 8: Construction of the multipoint meat temperature probe
1 NTC sensor connector 4 NTC sensor 1
2 NTC sensor connector 5 NTC sensor 2
3 NTC sensor connector 6 NTC sensor 3

Design and function
2016-03-10 / DIS 184_58300000140186_ara_en_k Copyright by BSH Hausgeräte GmbH Page 14 of 181
3.3 Brushless direct current motor
A BrushLess Direct Current motor (= BLDC motor) is an Electronically
Commutated motor (= EC motor).
3.3.1 Structure
In a BLDC motor there is no electrical contact for between the movable rotor and
the fixed stator.
The movable rotor consists of permanent magnets. The fixed stator consists of
coils that are controlled in sequence by the motor electronics. This creates a rotary
field.
Fig. 9: An external rotor motor assembly
1 Motor electronics 3 Magnets (rotor)
2 Coils (stator) 4 Motor housing (rotor)
A distinction is made between internal and external rotor motors. For internal rotor
motors, the movable rotor with the magnets is on the inside and the fixed stator is
on the outside. For external rotor motors, the movable rotor with the magnets is on
the outside and the fixed stator is on the inside.
Internal rotor motors are more efficient than external ones, but external rotor
motors have a higher torque than internal ones.
The motor electronics is made up of the power electronics and the control
electronics. The motor electronics generates the voltage with which the individual
coils are controlled.
Power transistors, for example power MOSFETs (Metal Oxide Semiconductor Field
Effect Transistors) are used for this circuit.
3.3.2 Function and model variant
The motor is operated with direct current. Contrary to their name, the functional
principle is not based on that of a direct current motor, but on that of a three-phase
synchronous motor with excitation by means of a permanent magnet. The coils
create a rotating magnetic field, which pulls the permanent magnets with it.
There are motors with at least two or with many coils. Depending on the number of
the coils, the coils are controlled single-phase, two-phase or three-phase.
The efficiency is greater for three-phase controls than for single-phase controls.
The torque is greater for twelve coils than for four.
Fig. 10: BLDC motor, 4-pole, single-phase, for appliances without pyrolytic self-
clean systems
Fig. 11: BLDC motor, 12-pole, three-phase, for appliances with pyrolytic self-
clean systems

Design and function
2016-03-10 / DIS 184_58300000140186_ara_en_k Copyright by BSH Hausgeräte GmbH Page 15 of 181
3.3.3 Commutation
Commutation is the process in which a current flow passes from one path to
another. There is natural and forced commutation.
Natural commutation is present if the feed voltage originates from an alternating
current or three-phase mains and the current path switching occurs due to its
polarity reversal.
Forced commutation is present if the feed voltage does not originate from an
alternating current or three-phase mains and the current path switching occurs by
means of a control.
EC motors use forced commutation.
Fig. 12: Basic circuit electronic commutation
red coil = north pole / green coil = south pole / grey coil = countervoltage
The big advantage of an EC motor is that the electronic commutation can be
made dependent on the rotor position, rotor speed and torque. The electronic
commutation thus becomes a controller. The way in which the rotary field is
generated determines the characteristic of the EC motor.
Fig. 13: Basic curve showing the torque and (positive/negative) currents in
phases L1, L2 and L3, depending on the rotation angle 0° to 360° for a
block commutation
Fig. 14: Rotary field
red coil = north pole / green coil = south pole / grey coil = countervoltage

Design and function
2016-03-10 / DIS 184_58300000140186_ara_en_k Copyright by BSH Hausgeräte GmbH Page 16 of 181
There are different ways of measuring the rotor position and speed:
•Sensor-controlled commutation
- Hall or optical sensors are used to determine the position of the rotor. The
advantage of the sensor-controlled commutation is that it also works for
very low torques or when stationary.
•Sensorless commutation
- The countervoltage in the coils, analysed by the motor electronics, is
used to determine the position of the rotor. A minimum rotational speed is
required in order to analyse the countervoltage. For this reason, EC motors
are switched idle until the minimum rotational speed is reached.
New procedures allow precise control even below the minimum speed by using
targeted brief current pulses, which do not move the motor but are influenced by
the rotor’s magnetic field.

Design and function
2016-03-10 / DIS 184_58300000140186_ara_en_k Copyright by BSH Hausgeräte GmbH Page 17 of 181
3.4 Steam generation
Fig. 15: Overview of the components
1 Water tank in the housing 4 Steam generator
2 Water pump 5 Steam hose
3 Steam electronics
The water pump pumps the water from the water tank to the steam generator.
The water level in the steam generator is monitored by a water level sensor.
The steam electronics will switch the heater on if there is sufficient water in the
steam generator.
The steam that is created flows through the steam hose into the interior of the
cooking compartment.
The duration and amount of steam generation depends on the programme that is
selected.

Design and function
2016-03-10 / DIS 184_58300000140186_ara_en_k Copyright by BSH Hausgeräte GmbH Page 18 of 181
3.5 Steam generator
Fig. 16: Components of the steam generator
1 Water level sensor 5 Heater
2 Housing 6 Water connection
3 Steam outlet 7 Electrical connection
4 Seal 8 Support
3.5.1 Function of the steam generator
The steam generator generates steam, which is conducted to the cooking
compartment.
The steam generator is filled with water via the water connection until the water
reaches the water level sensor. Depending on the intended heat setting, the steam
generator continues to be filled with water for an additional 3 to 12 seconds. Now
the amount of water in the steam generator is approximately 120 ml.
The heater switches on and steam is generated until the boiling water no longer
touches the water level sensor. Now the amount of water in the steam generator is
approximately 60 ml.
The steam generator is refilled. This cycle continues as long as steam is required.
When the appliance is switched off, the steam generator is refilled to 120 ml. Water
is then pumped out of the tank for approximately 50 seconds. This prevents the
water pump from draining (noise reduction).
Finally the heater is switched on for 8 seconds to dry the steam generator.
3.5.2 Heater
Fig. 17: Design of the heater
1 Thick-film heating element 4 High-temperature insulation layer
2 Low-temperature insulation layer 5 Stainless steel plate
3 E-Fast Temperature sensor
The mean operating temperature of the heating element is 170 °C.

Design and function
2016-03-10 / DIS 184_58300000140186_ara_en_k Copyright by BSH Hausgeräte GmbH Page 19 of 181
The heating element is switched off at 280 °C.
The maximum temperature of the heating element is 350 °C.
Fig. 18: Heater connections
1 Earth connection 4 Heater connection 800 W
2 E-Fast Temperature sensor connection 5 Neutral conductor connection
3 Heater connection 400 W 6 Water connection

Design and function
2016-03-10 / DIS 184_58300000140186_ara_en_k Copyright by BSH Hausgeräte GmbH Page 20 of 181
3.6 Double pump
The double pump consists of two pumps that are mounted on a carrier on a low-
vibration rubber bearing. The voltage supply is provided by a common connector
socket.
Depending on which pump is being operated, the water is pumped from the water
tank to the steam generator (filling) or from the steam generator to the water tank
(draining).
3.6.1 Double pump in appliances without microwave.
Fig. 19: Position and connections for the pump
1 Connection to the tank 2 Connection to the steam generator
3.6.2 Double pump in appliances with microwave
Fig. 20: Position and connections of the pump
1 Connection to the steam generator 2 Connection to the tank