STIEBEL ELTRON LWZ 170 User manual

279161
Operating and installatiOn instructiOns
central ventilatiOn unit
» lWZ 170
» lWZ 170 plus
» lWZ 270
» lWZ 270 plus

2
Symbols used in these instructions
Observe the following safety instructions:
Please note:Warning about possible
dangers
i
Note: Important information
Content
1. Operating instructions for
users and contractors 3
1.1 Equipment description 3
1.2 Particular features of the LWZ...plus 4
1.3 User interface 5
1.4 Operation 5
1.5 Maintenance and cleaning 6
2. Installation instructions for
contractors 7
2.1 Specication 7
2.2 Installation 8
2.3 Installation on the air side 9
2.4 Electrical connection 10
2.5 Frost protection 10
2.6 Settings 13
Commissioning report 16
2.7 Fault analysis 16
2.8 Maintenance and cleaning 17
3. Environment and recycling 18
4. Customer service and warranty 19

3
1. Operating instructions for users and contractors
1.1 Equipment description
1.1.1 General
The LWZ 170/270..plus can recover up to
90 % of the latent energy in extract air.This
is made possible by the use of new types of
countercurrent heat exchangers.The air flow
rate is regulated independently by two energy-
saving DC fans.This makes the LWZ 170/270..
plus a particularly powerful and highly efficient
central unit for ventilating several rooms.
The plus version is equipped with an integral
bypass damper that channels cool ventilation
air into rooms on hot summer nights.
1.1.2 Description of functions
A central control unit safeguards the reliable
equipment operation and minimum energy
consumption whilst maintaining maximum
comfort. It ensures that the selected set air
flow rates remain constant.
The LWZ 170/270..plus is equipped with a
user interface with display.That enables an
infinitely variable adjustment of the air flow
rate as well as the scanning of operating details
on the display, without requiring the device to
be opened.
Settings in the program of the central
controller can be called up and modified at
the user interface.
At a glance
Switching the device ON and OFF
Displaying the fan stage and the
air flow rate
Infinitely variable flow rate selection
Scanning temperatures and status
Fault display
Optionally with integral bypass
(plus version)
1.1.3 Function
The LWZ 170/270 central ventilation unit
uses two fans and separate ducts to draw,
respectively via individual filter mats, outside
air into the building and extract air from
rooms that are subject to odour or humidity
loads (kitchen, bathroom, toilet, conservatory).
Both air streams are routed via a
countercurrent heat exchanger where the
outside air absorbs energy that is transferred
from the extract air.The airways are separated
from each other, thereby preventing odours
from being transferred between outside
air and extract air, subject to the correct
operation of the equipment.
The heated fresh air is blown into the
accommodation via suitable air ducts and
adjustable vents (available as accessories),
whilst the cooled extract air is expelled
through the roof or through a wall.
1.1.4 Shutting the equipment down
Even during longer periods away from home,
it is recommended that the equipment should
be allowed, via the remote control, to run
at switch position 1. Should the equipment,
nevertheless, be switched off for longer
periods, pull its power supply plug from the
socket. Prior to this disconnection, switch OFF
the device via the user interface.
1.1.5 Incorrect operation
Never
use extract air loaded with grease, explosive
gases, dust or adhesive aerosols
install the unit outdoors
connect cooker hoods and dryer exhausts
to the ventilation system.
Only qualified contractors are permitted to
work on the equipment. Never adjust the
ventilation and extract air valves inside the
rooms.These have been adjusted during
commissioning. Never make any modifications
to the internal equipment electrics or controls.
Trouble-free operation can only be ensured
with a closed filter door.
–
–
–
1.1.6 Regulations and standards
DIN 18017 - Ventilation of bathrooms and
flush toilets
DIN 1946 T6 E - Ventilation and air
conditioning, domestic ventilation
DIN 2088 - Domestic ventilation equipment
VDI 2087 - Air ducts [or local regulations]
Relevant Building Regulations
Important information
Please note:The ventilation device
must only be installed and
maintained by qualied contractors.
Operating and installation
instructions
i
Note: Keep these operating and
installation instructions safely and
pass them on to any new user, should the
equipment change hands, and let your
contractor check their content in
conjunction with any maintenance and
repair work.
Function diagram
Outside air / ventilation air
Extract air / expelled air
Connector
Room air temperature sensor
Countercurrent heat exchanger
Extract air filter
Outside air filter
Outside air temperature sensor
Condensate drain connection
Extractor fan
User interface
Control PCB
Outside air fan
Cable entries
1
2
3
4
5
6
7
8
9
10
11
12
12
7
1
2
3
4
5
6
11
10
9
8
C26_04_01_0190

4
1.2 Particular features of
the LWZ...plus
The LWZ...plus contains an integral bypass
module with one N/O and one N/C bypass
damper.This module reduces the heat transfer
at specific temperatures in summer.
When the bypass damper is closed, outside
air flows through the LWZ heat exchanger.
With opening the bypass damper, the heat
exchanger is closed on its ventilation air
side.This channels the outside air through
the bypass, in other words past the heat
exchanger; hence it acts as ventilation air for
the dwelling.
Consequently, no heat is transferred to the
ventilation air. Essentially, this function is utilised
in summer. During the day, the heat exchanger
ensures that the house is not overheated.
At night, when the outside temperature is
lower than the room temperature, the bypass
damper opens, and the cool outside air is
directly channelled into the living space.
General function (schematic diagram)
Extract air / expelled air
Outside air / ventilation air
Bypass damper closed Bypass damper open
Heat exchanger
Bypass damper
Bypass module
LWZ 170/270
A
B
C
D
Bypass damper
Bypass damper control
Closing facility
1
2
3
C26_04_01_0220
C26_04_01_0225
1
3
2

5
1.4 Operation
The remote control enables the operation
of the LWZ between stage 1 and 3. For
this, observe the operating and installation
instructions of the respective remote control.
Stage 2should be treated as the standard
ventilation, stage 3as the demand ventilation,
e.g. party stage (quick ventilation) and stage
1as the minimum setting (for example, when
you are away).
The user control at the device is limited to
switching the device ON and OFF.
Your contractor has set the LWZ specifically
to suit the conditions of your home and to
your personal requirements. Never change
any system-specific settings via the user
interface.
Starting
Plug the power supply cable
into the socket and start
the device by simultaneously
pressing programming keys
“OK”and “+”.
(Only possible if the device
was switched off with the
program keys).
On the display, the first figure
represents the position of the
three-stage switch.
Stopping
Stop the device by
simultaneously
pressing the program keys
“OK” and “–”.The display
shows OFF.
Pull the power supply plug
from the socket; the device is
now disconnected from the
power supply.
3 seconds
3 seconds
1.3 User interface
The LWZ 170/270..plus units are equipped
with a user interface with LED.
Settings in the program of the central
controller can be called up and modified at
this user interface.
The user interface is equipped with four keys
and one display.
The left area of the display shows the fan
operation or the parameter type.The right
area displays the current value, e.g. air volume.
Example:
The display now indicates that the device
is operating at stage 1 at an air volume of
100 m3/h.
1
2
3
4
5
C26_04_01_0194
C26_04_01_0196
The parameters listed in the table can be
called up with keys “+” and “–”.The display
reverts to the standard operating mode
display if no key is pressed for 5 minutes. Key
“+” enables you to scroll through the menu.
Key “–” only enables the return to parameter
1. Set values cannot be adjusted in this menu.
Parameter Display
(example) Description Note
1 1.100 Current setting/extract air volume [m3/h]
2 C 0 Message code operating mode C0 = No message
C3 = The ventilation air fan runs in the operating mode ‘constant pressure’
C6 = The extract air fan runs in the operating mode ‘constant pressure’
C7 = Correction maximum air volume
3 bP.1 Bypass status
(only for integral bypass)
0 = Bypass damper closed / 1 = Bypass damper automatic /
2 = Minimum ventilation air
4 tP.9 Outside air temperature [°C] For temperatures below minus (< 0 °C) display tP.9.
5 tS.21 Extract air temperature [°C]
6 In.0 No function
Display
Key “OK” (operate, finished,
reset filter display)
Increase parameter value key
Function key
Reduce parameter value key
1
2
3
4
5

6
1.5 Maintenance and
cleaning
Maintenance by the user is limited to the
regular cleaning and replacing of the filter.
The filter will only need cleaning when the
respective letter combination “FIL” is shown
on the display, but should be cleaned at
least annually. Never operate the equipment
without the filter.
A contractor should check or clean the heat
exchanger, the condensate drain and the fans
at least once a year.
Cleaning and replacing the lter
1Switch OFF the device via the user
interface. For this, press and hold
down simultaneously “OK” and “–” for
3 seconds.
2Open the filter door.This enables you to
pull out both filters and check them for
contamination.
1
2
3
4
Replace the filters if they are heavily
soiled (solid layer of dust on the top of
the filter mat). Clean the filters with a
vacuum cleaner, if they are only lightly
soiled.These filters cannot be washed.
Washing would mat the fabric, leaving too
little air to flow through the filter.
3After inserting the filters, close the filter
door and restart the device via the user
interface (simultaneously press both
“OK” and “+” for 3 seconds).
Please note:When re-inserting the
lters ensure that the solid, ne
pored side is turned towards the l.h. side,
i.e. towards the heat exchanger.
4Reset the filter status display by pressing
“OK” (1 second).
The display flashes briefly as confirmation
that the filter status has been reset. Then
the operating mode display “operation”
will be shown again.
Please note:All other work on the
equipment must only be carried out
by qualified contractors. Never adjust the
ventilation and extract air valves inside the
rooms.These have been adjusted during
commissioning. Never make any
modifications to the internal equipment
electrics or controls.Trouble-free
operation can only be ensured with a
closed filter door.
Filter change
C26_04_01_0222

7
2. Installation instructions for contractors
Accessories Part no:
Filter mat set; content: 10 pce. 16 09 50
Remote control unit FEZ 18 53 58
Remote control FEQ 18 98 00
Three-stage switch 16 25 51
All ventilation pipes, valves and similar equipment are also available from Stiebel Eltron.
2.1 Specication
(The details on the equipment type plate apply)
Type LWZ 170 (170 plus) LWZ 270 (270 plus)
Part no: 22 12 34 (22 12 35) 22 12 36 (22 12 37)
Voltage/Frequency V, Hz 1/N/PE ~ 230 V 50 Hz 1/N/PE ~ 230 V 50 Hz
Max. power consumption A 1.1 (1.17) 2.01 (2.08)
Power consumption W 16 - 130 12 - 230
Air volume flow m³/h 50 - 250 50 - 350
Protection level toVDE IP 31 IP 31
Externally available max. static pressure differential Pa 160 at 250 m3/h 160 at 350 m3/h
Max. ambient temperature °C 60 60
Filter class G 3 G 3
Air duct connection DN 160 160
PE condensate drain connection mm 13 13
Height mm 602 602
Width mm 675 675
Depth mm 445 (525) 455 (535)
Weight excl. packaging kg 31 (35) 31 (35)
Sound pressure level tested 1 m from the
unit in accordance with EN 255 T7
dB(A) 28.5 at 100 m³/h, 40 Pa)
38 at 150 m³/h, 80 Pa)
46.5 at 225 m³/h, 160 Pa)
33 at 100 m³/h, 40 Pa)
43.5 at 200 m³/h, 80 Pa)
51.5 at 300 m³/h, 160 Pa)

8
2.2 Installation
Transport
To protect the equipment against damage, it
must be transported to the installation room
inside its original packaging.
Positioning the equipment
Install the equipment in a suitable location
which is free from frost (as centrally as
possible to achieve the shortest possible air
ducts). For this, unscrew the top two Philips
screws at the back of the device, and secure
one of the two rails (G) to the device using
the screws. Fit the other rail as a retainer to
the wall.
Before securing the rail to the wall, ensure
that the wall is sound and strong enough to
bear the weight of the device. Subject to wall
structure, use suitable rawl plugs and screws
to mount the rail to the wall.To prevent
sound transmission, use washers (D) and the
channel section (C) in accordance with detail
X. Before mounting the device by hanging it
into the rail, fit the spacers (E) supplied to the
back of the device.
Fit the equipment so that it is level to ensure
that the condensate drains off properly.
Ensure sufficient space for maintenance in front
of the equipment. Maintain a distance from the
ceiling of at least 250 mm. Maintain a minimum
clearance towards the wall of 50 mm.
C26_04_01_0230
26_04_01_0192
Condensate drain connection
The equipment is supplied with an angled
condensate connector and a condensate drain
hose with an internal diameter of 13 mm and
a length of 1500 mm. Insert the condensate
drain connector into the bottom of the
device.
For this, use PTFE tape on the connector
thread.
You can adjust the condensate drain
connector, whilst tightening it, into its required
position.
i
Note: Never kink the hose, to ensure
the condensate drains perfectly.The
slope must be at least 10%, and the device
must be level.
After completing the installation, check
the function, draining capability and water
tightness of the condensate drain. For this,
pour approx. 1 l of water into the condensate
pan.The entire water volume must drain off
swiftly.
I Ventilation air
II Expelled air
III Extract air
IV Outside air
A Power supply
B Interface for
remote control
C Condensate drain
D Channel section (rubber)
E Washer (rubber)
F Spacer
G Rails
F
E
C
B
D
G
Detail X
A
Condensate drain
Dimensions in mm
( ) - Dim. = LWZ 270...plus
min. 10% slope
min. 10% slope

9
Ventilation and extract air valves
Ventilation and extract air valves for the living
space are available for wall or ceiling mounting.
During installation, ensure a thorough
ventilation of the room.
Overow apertures
The living rooms and bedrooms only
receive air, and the rooms loaded with
odour and humidity only have air extracted.
Consequently, fit interconnecting ventilation
grilles into adjoining doors or walls or increase
the air gap below a door to ≥8 mm, to
ensure an unrestricted air flow between
rooms.
2.3 Installation on the air
side
The installation is completed with
commercially available slip tubing and profiles.
This installation material may be obtained
from Stiebel Eltron.
During the installation, ensure that no metal
swarf enters the pipe system. However, should
this occur, remove this debris, otherwise the
fans may be damaged.
Use thermally insulated pipes to construct the
outside air and expelled air ducts.
Thermally insulate these pipelines, if they are
constructed from non-insulated pipes and
profiles.
Where the ventilation air and extract air ducts
are routed through unheated rooms, thermally
insulate those too.
Please note: Never connect cooker
hoods and dryers to the ventilation
system.
Silencers
Generally, fit one silencer each in the
ventilation air and the extract air duct
Additional silencers are recommended
upstream of bedrooms and living rooms (or in
rooms where noise should be kept down and
where noise transmission should be avoided).
If a room with a high noise level must be
ventilated, install additional silencers in the
approach to and the exit from such rooms
to reduce sound transmission into adjacent
rooms.
Clean-out apertures
Air ducts must be checked and possibly
cleaned at regular intervals. Releasing the air
duct from the device or at the extract air and
ventilation air valves enables the inspection
and cleaning.
External wall outlet
Supply fresh air from a location where
contamination (dust, soot, odours, flue gas,
expelled air) is as low as possible.
When creating the external wall outlet ensure,
that a “short circuit” between the fresh air
inlet and air outlets is avoided. It would be
practical to use our external wall inlet and
outlet grille (part no: 07 18 32).
Safety instructions
If the dwelling contains combustion equipment
(tiled stoves, fire places, wall mounted gas
heaters, etc.), ensure that such combustion
equipment is supplied with combustion
air separate from the ventilation system
(check with your local flue gas inspector,
as requirements vary across regions and
countries).
When operating a dryer or a cooker hood
that extracts air, ensure also, that a sufficiently
large air volume flow is supplied to that
equipment, independent of the ventilation
equipment.
Fan curve LWZ 170 (plus)
Statischer Druck [Pa]
Volumenstrom [m³/h]
Statischer Druck [Pa]
C26_04_01_0223C26_04_01_0224
Volumenstrom [m³/h]
max. characteristic curve for max. volume flow
max. characteristic curve for max. volume flow
Fan curve LWZ 170 (plus)
Static pressure [Pa]
Static pressure [Pa]
Air volume [m³/h]
Air volume [m³/h]

10
2.4 Electrical connection
The device is supplied fully wired, and should
be plugged into an easily accessible mains
socket.
A 1 m long LV cable for the connection of a
remote control is supplied with the device.
ObserveVDE 0100 [or local regulations] and
the regulations of your local power supply
utility.
2.4.1 Remote control unit FEZ
The FEZ remote control enables the selection
of one of the three preset air flow rate stages.
The operating mode selector offers the
functions: party, day/night, automatic and
standby (OFF).The programmable analog
time switch controls the changeover between
day and night mode. An indicator signals the
requirement for changing the air filter.
2.4.1 Remote control FEQ (part no: 189800)
The FEQ remote control enables the selection
of the three preset air flow rate stages.
The operating mode selector offers the
functions: party, standard/setback mode,
automatic and standby (OFF).
2.4.2 Three-stage switch (part no: 162551)
The three-stage switch enables the selection
of the three preset air flow rate stages.
The operating mode selector offers the
functions: party, day and night mode.
2.4.3 Installation of remote control units
Connect the respective remote control,
subject to the equipment-specific operating
and installation instructions or in line with the
connection diagram on pages 11 and 12, to
the equipment using the interface and the
connecting cable supplied.
Please note: Route the LV cable of
the remote control units and the
power supply cable of the ventilation
device separately.
2.5 Frost protection
On account of the high heat availability factor,
low outside temperatures result in the outside
air being cooled down so severely that any
condensate that is created in the process may
freeze.
The frost monitoring ensures that the extract
side of the heat exchanger cannot freeze
up.This is achieved by the ventilation air
flow and the extract air flow being brought
out of balance, subject to the outside air
temperature and the pressure drop in the
heat exchanger.This effectively prevents the
unit freezing up.
The ventilation air fan may also, for short
periods, be switched OFF at very low outside
temperatures.
The imbalance and the shutting down of the
ventilation air fan can be prevented by pre-
heating the outside air through an electric
pre-heater bank or by means of a ground heat
exchanger.

11
A Three-stage switch
B Remote control FEZ
C Remote control FEQ
D Room temperature sensor
E Control PCB
F Ventilation air fan
G Extractor fan
H Outside temperature sensor
J User interface
Wiring diagram LWZ 170, LWZ 270
A1 brown
A2 blue
A3 green/yellow
A4 black
A5 white
A6 No. 1
A7 No. 2
A10 yellow
C26_04_01_0215
Day
Day
Day
Out
Out

12
Wiring diagram LWZ 170 plus, LWZ 270 plus
A Three-stage switch
B Remote control FEZ
C Remote control FEQ
D Room temperature sensor
E Control PCB
F Ventilation air fan
G Extractor fan
H Outside temperature sensor
J User interface
K Damper control, slide grille
L Damper control
Bypass damper
M Bypass PCB
A1 brown
A2 blue
A3 green/yellow
A4 black
A5 white
A6 No. 1
A7 No. 2
A10 yellow
C26_04_01_0210
Day
Day
Day
Out Out

13
Parameter
no.
Display
(example) Description Note
1 2.100 Current setting/extract air volume [m3/h]
2 C 0 Message code operating mode C0 = No message
C3 = The ventilation air fan runs in the operating mode ‘constant pressure’
C6 = The extract air fan runs in the operating mode ‘constant pressure’
C7 = Correction maximum air volume
3 bP.1 Bypass status (only for integral bypass) 0 = Bypass damper closed / 1 = Bypass damper automatic /
2 = Minimum ventilation air
4 tP.9 Outside air temperature [°C] For temperatures below minus (< 0 °C) display tP.9.
5 tS.21 Extract air temperature [°C]
6 In.0 No function
7u.156 Current ventilation air volume [m3/h]
8u.156 Current extract air volume [m3/h]
9 t.180 Current pressure, ventilation air duct [Pa]
10 A.180 Current pressure, extract air duct [Pa]
11 u0.0 Frost protection status 0 = None, 1 t/m 4 = Pressure imbalance, 5 = Ventilation air fan OFF
12 St.9 Expelled air temperature
(sensor not provided as standard)
[°C] If not provided, St.75
13 Pt.18 Ventilation air temperature
(sensor not provided as standard)
[°C] If not provided, Pt.75
2.6 Settings
The four keys on the user interface have the
following functions:
• FFunction key / parameter menu
switching ON and OFF
• +Next parameter / increase value
• –Last parameter / reduce value
• OK Switching the settings menu ON
and OFF / manually resetting faults /
resetting the filter display
Other commands are issued by pressing the
following key combinations.
• F& +(set), Confirm parameter value
• F& –(reset), Resetting the parameter
to the factory default..
• OK & +(ON), Switch ON the device
• OK & –(OFF), Switch OFF the device
In these operating and installation instructions,
every operation using the function keys is
shown as the respective key in inverted
commas and emboldened.
Example: - press OK”
a Remote control stage
b Extract air volume
2.6.2 Calling-up selected values
Pressing “F” and “OK” simultaneously for
3 seconds enables all available data to be
called up. However, values cannot be adjusted
or modified in this menu.
This menu always opens in parameter 7 (see
the following table). Key “+” enables the data
to be called up, pressing “–” returns you to
parameter 1.
This menu is automatically cancelled if the
NO key is activated for 5 minutes, when the
display shows the standard operating mode
again.
2.6.1 Displaying selected values
This display shows as standard the current fan
stage and the respectively selected extract
air volume (operating mode).The fan stage
(stage 1, 2 or 3) is shown on the l.h. side of the
screen and the extract air volume is shown to
the right of the full stop.
In case of faults, the fault number is shown on
the display (see section 2.6 Fault analysis).

14
2.6.3 Adjusting the air volume
The air volume of the LWZ 170/270..plus for
the stages 1 to 3 are factory-set to 50, 100 and
150 m³/h.
Important:
Stage 1: must always be lower than stage 2;
Stage 2: must always be lower than stage 3;
Stage 3: adjustable between 50 and 180 m³/h;
The air volume of the higher stage is
automatically selected if one of the above
conditions is not met.
The air volume can be modified as follows
(as example, the air volume for stage 3 is
increased from 150 to 180 m³ /h):
1. Press “F” for 3 seconds
to activate the settings
menu.
2. Select the required
parameter with “+”:
U1 = stage 1
U2 = stage 2
U3 = stage 3
3. Press “OK” for 1 second
to display the value of
the selected parameter.
4. Keys “+” or “–” enable
the air flow rate to be
changed.
5.The modified value can now:
Abe saved;
Bnot be saved;
Creturn to the factory default.
ASimultaneously press
“F” and “+” (first “F,”
then “+”) to save
the modified value;
the modified value
begins to flash 3 x as
confirmation.
Press “OK” to return
to the settings menu;
if required, further
values can now be
changed (see steps
2 to 5).
BPress “OK” to return
to the settings menu
without saving the
modified value; the
previously active
value is maintained.
If required, further
values can be
modified (see
steps 2 to 5).
C Simultaneously press
“F” and “–” to return
to the factory-set air
flow rate.The factory
setting flashes 3 x as
confirmation.
Press “OK” to return
to the settings menu;
if required, further
values can now
be changed (see
steps 2 to 5).
6. Press “F” for 1 second
to exit the settings
menu.
2.6.4 Changing parameter settings
These parameters must only be changed by
a contractor, as changing these parameter
settings can impair the correct function of
the device.
For factory settings, see the commissioning list
on page 13.
I 1 Pressure imbalance
This enables the creation of a fixed
positive (+) or negative (-) pressure in
the house.
Positive pressure imbalance (+):
The extract air fan ventilates by a fixed
value [m³/h] less than the ventilation air fan.
Negative pressure imbalance (-):
The ventilation air fan ventilates by a
fixed value [m³/h] less than the extract
air fan.
I 2 Remote control, open switching contact
(night)
This parameter determines which fan
stage is activated by an open switching
contact.
I 4 Control cable 0 OFF
This parameter determines which fan
stage will be activated with the control
cable OFF.
I 5 Control cable 2 (day)
This parameter determines which fan
stage will be activated with the control
cable 2.
I 6 Control cable 3 (party)
This parameter determines which fan
stage will be activated with the control
cable 3.
I 7 Is a pressure imbalance permissible?
This determines whether, for example,
the frost protection can interfere with
the pressure balance.
I 8 Bypass mode
This mode enables a selection from three
options:
Mode 0 Bypass damper not
activated
Mode 1
(standard)
Bypass damper, if
installed, is opened
at the corresponding
temperature conditions
Mode 2 Ventilation air fan runs
at top speed, if the
temperature conditions
are met

15
Changing the selected values from the
operating mode “Operation” requires the
following steps: Parameter I7 is used as an
example (change from 1 to 0).
1. Press “F” for 3 seconds
to activate the settings
menu.
2. Simultaneously press
“F” and “OK” for
3 seconds to activate
the extensive installer
parameter set.
3. Using both “+” and “–”
enables you to
locate the required
parameters.
4. The set value for the
required parameter is
displayed by pressing
“OK”.
5 Keys “+” and “–” enable
the value to be
changed.
6. The modified value can now:
A be saved
B not be saved; or
C return to the factory settings.
A Simultaneously
press “F” and “+”
(first “F”, then “+”),
to save the modified
value; the modified
value flashes 3 x
on the display to
confirm it has been
saved; the displayed
modified value is
then maintained.
Press “OK” to return
to the settings menu;
if required, further
values can now
be changed (see
steps 2 to 5).
B Press “OK” to return
to the settings menu
without saving the
modified value; the
previously active
setting is maintained.
C Simultaneously
press “F” and “–”
(first “F” then “–”), to
return to the factory
default.The factory
setting flashes 3 x
on the display as
confirmation.The
factor default is
maintained, the
modified value is
dismissed. Press
“OK” to return to
the settings menu.
I 9 Bypass hysteresis
This enables the indication by how many
degrees the room temperature can be
lowered before the bypass closes or the
ventilation air fan ramps up to nominal
speed.
I 10 Constant pressure OFF
This enables the determination whether
the fans should run at a constant flow
rate at all times or whether, if a certain
pressure drop has been exceeded, the
fan changes to constant pressure.
I 13 Filter message
Determines whether the filter message is
shown on the display.
I 3 / I 11 / I 12 and I 14
For the LWZ 170/270..plus, these
parameters are without function.
7 Press “F” for 1 second
to exit the settings
menu.

16
Parameter Description Setting range Factory default System value
U 1 Volume stage 1 50 - 300 LWZ 170
50 - 400 LWZ 270
100 LWZ 170
100 LWZ 270
U 2 Volume stage 2 50 - 300 LWZ 170
50 - 400 LWZ 270
150 LWZ 170
200 LWZ 270
U 3 Volume stage 3 50 - 300 LWZ 170
50 - 400 LWZ 270
225 LWZ 170
300 LWZ 270
U 4 Minimum outside temperature for bypass 5 - 20 10
U 5 Minimum room temperature for bypass 18 - 30 22
U 8 Humidity sensor 0,1 0 (OFF)
I 1 Fixed pressure imbalance – 100.. + 100 0
I 2 Remote control, open switching contact 0, 1, 2, 3 1
I 3 No function 2.3 2
I 4 Control cable OFF 0, 1, 2, 3 0
I 5 Control cable 20, 1, 2, 3 2
I 6 Control cable 30, 1, 2, 3 3
I 7 Pressure imbalance permissible 0, 1 1 (yes)
I 8 Bypass mode 0, 1, 2 1
I 9 Bypass hysteresis 0 - 5 2
I10 Constant pressure switched OFF 0, 1 0 (no)
I11 Heating mode 0, 1, 2, 3 0
I12 Offset temp. pre-heater -30 - +30 0.5
I13 Filter message ON/OFF 1, 0 1 (ON)
I14 Auxiliary PCB 1, 0 0
Fault code Cause Installer action
F2 The ventilation air fan has stopped. Replace the ventilation air fan.
F5 The extract air fan has stopped. Replace the extract air fan.
F9
Outside air temperature sensor
faulty.
Check the leads from the sensor to the central
control PCB.
Check the lead connection at the sensor.
Replace the sensor.
F10
Extract air temperature sensor
faulty.
Check the leads from the sensor to the central
control PCB.
Check the lead connection at the sensor.
Replace the sensor.
2.7 Fault analysis
When the control unit recognises a fault, the
display will indicate an alpha-numerical code.
Here, fault F9 is shown as an example, that
means there is a fault in the outside air duct.
The device remains in this fault condition until
the respective problem has been resolved.
Afterwards, the device will automatically reset
(auto reset), and the display returns to the
operating mode “Operation”.
The table provides a summary of the types
of faults, their possible causes as well as the
corresponding measures to remove them.
Commissioning report
26_04_01_0211

17
2.8 Maintenance and cleaning
Maintenance by contractors includes the
cleaning of the heat exchanger and the fans.
Subject to operating mode, these maintenance
steps are required every three years.
1Switch OFF the device. For this,
simultaneously press “OK” and “–” for
3 seconds.
Pull the mains plug and remove the filter
doors.
2Pull out the filter.
3Remove the front panel.
i
Note: Remove the bypass module
on the plus version, see 2.8.1 on
page 18.
4Carefully pull the heat exchanger out of
the device using the handle.
5Clean the heat exchanger with a solution
of warm water and conventional washing-
up liquid (never use solvents).Then rinse
the heat exchanger with warm water.
Finally, let the heat exchanger dry.
Please note: On the plus version, rst
remove the lock (slider) prior to
cleaning.
6Remove the user interface.
7Pull all plugs from the central control
PCB that are connected with the panel
through which the leads/cables run. Undo
the earth cable from the device body.
8Carefully pull the fan housing forwards
and out of the unit; then remove the EPS
enclosure.
9Clean fans with compressed air or a
paint brush. During cleaning, ensure
that the vanes are not bent, otherwise
the resulting imbalance would create
additional noise. Never move the
balancing weights on the vanes.
10 Clean the EPS enclosure with a solution
of warm water and conventional
washing-up liquid (never use solvents)
and flush with clear hot water.Then let
the EPS enclosure dry.
The device is reassembled in reverse order:
Refit the EPS enclosure to the fan casing.
Refit the fan casing.
Reconnect the earth cable and reconnect
the plugs pulled from the control PCB.
Install the user interface.
Reinstall the heat exchanger.
Install the bypass module (only plus
version). During this work ensure, that the
cables attached to the servomotors are
correctly attached.
Fit the front panel.
Always insert the filter with the clean side
towards the heat exchanger.
–
–
–
–
–
–
–
–
Close the filter door.
Plug the power cable into a mains socket.
Switch ON the device via the user interface
(simultaneously press “OK” and “+” for
3 seconds).
After completing the maintenance and
cleaning work, check the device function.
–
–
–
1 2 3
4 5 6
7
89
10
C26_04_01_0228

18
2.8.1 Removing the bypass module
Pull the servomotor cables from the bypass
damper and the heat exchanger.
Undo 2 Allen screws respectively from the
top and bottom of the bypass module using
the key supplied, but do not remove the
screws.
The bypass module can now be removed.
26_04_01_0229

19
3. Environment and
Recycling
Recycling of obselete appliances
Appliances with this label must not be
disposed off with the general waste.
They must be collected separately and dis-
posed off according to local regulations.
For guarantees please refer to the re-
spective terms and conditions of supply
for your country.
The installation, electrical con-
nection and rst operation of
this appliance should be carried out
by a qualied installer.
The company does not accept li-
ability for failure of any goods
supplied which are not installed in
accordance with the manufacturer‘s
instructions.
4. Guarantee

20
Austria
STIEBEL ELTRON Ges.m.b.H.
Eferdinger Str. 73 | A-4600 Wels
Tel. [phone] | Fax [phone]
Email [e-mail]
www.stiebel-eltron.at
Belgium
STIEBEL ELTRON Sprl/Pvba
Rue Mitoyenne 897 | B-4840 Welkenraedt
Tel. [phone] | Fax [phone]
Email [e-mail]
www.stiebel-eltron.be
CCzech Republik
STIEBEL ELTRON spol. s r.o.
K Hájům 946 | CZ-15500 Praha 5-Stodůlky
Tel. [phone] | Fax [phone]
Email [e-mail]
www.stiebel-eltron.cz
Denmark
Exclusive Distributor.
PETTINAROLI A/S
Madal Allé 21 | DK-5500 Middelfart
Tel. [phone] | Fax [phone]
Email [e-mail]
www.pettinaroli.dk
France
STIEBEL ELTRON S.A.S.
7-9, rue des Selliers
B.P. 85107 | F-57073 Metz-Cédex 3
Tel. [phone] | Fax [phone]
Email [e-mail]
www.stiebel-eltron.fr
Great Britain
Exclusive Distributor.
Applied Energy Products Ltd.
Morley Way | GB-Peterborough PE2 9JJ
Tel. [phone] | Fax [phone]
Email [e-mail]
www.applied-energy.com
Hungary
STIEBEL ELTRON Kft.
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Tel. [phone] | Fax [phone]
Email [e-mail]
www.stiebel-eltron.hu
Netherlands
STIEBEL ELTRON Nederland B.V.
Daviottenweg 36 | Postbus 2020
NL-5202 CA‘s-Hertogenbosch
Tel. [phone] | Fax [phone]
Email [e-mail]
www.stiebel-eltron.nl
Poland
STIEBEL ELTRON sp.z. o.o
ul. Instalatorów 9 | PL-02-237 Warszawa
Tel. [phone] | Fax [phone]
Email [e-mail]
www.stiebel-eltron.com.pl
Russia
STIEBEL ELTRON RUSSIA
Smolenskaya square, building 3
Business Center "REGUS"
15th oor, ofce 1508 | 121099 Moscow
Tel. [phone] | Fax [phone]
Email [e-mail]
www.stiebel-eltron.ru
Sweden
STIEBEL ELTRON AB
Friggagatan 5 | SE-641 37 Katrineholm
Tel. [phone] | Fax [phone]
Email [e-mail]
www.stiebel-eltron.se
Switzerland
STIEBEL ELTRON AG
Netzibodenstr. 23 c | CH-4133 Pratteln
Tel. [phone] | Fax [phone]
Email [e-mail]
www.stiebel-eltron.com
Thailand
STIEBEL ELTRON Asia Ltd.
469 Moo 2, Tambol Klong-Jik
Ampur Bangpa-In | Ayutthaya 13160
Tel. [phone] | Fax [phone]
Email [e-mail]
www.stiebeleltronasia.com
United States of America
STIEBEL ELTRON Inc.
17 West Street | West Hateld MA 01088
Tel. [phone] | Fax [phone]
Email [e-mail]
www.stiebel-eltron-usa.com
Deutschland
STIEBEL ELTRON GmbH & Co. KG
Dr.-Stiebel-Straße | D-37603 Holzminden
Tel. [phone] | Fax [phone]
Email [e-mail]
www.stiebel-eltron.de
Verkauf Tel. [phone] | Fax [phone] | [e-mail]
Kundendienst Tel. [phone] | Fax [phone] | [e-mail]
Ersatzteilverkauf Tel. [phone] | Fax [phone] | [e-mail]
Vertriebszentren Tel. [phone] | Fax [phone]
Irrtum und technische Änderungen vorbehalten | Subject to errors and technical changes! | Sous réserve d‘erreurs et de modifications
techniques! · Onder voorbehoud van vergissingen en technische wijzigingen! | Salvo error o modificación técnica! | Rätt till misstag och
tekniska ändringar förbehålls! | Excepto erro ou alteração técnica | Zastrzeżone zmiany techniczne i ewentualne błędy | Omyly a technické
změny jsou vyhrazeny! | A muszaki változtatások és tévedések jogát fenntartjuk! | Âîçìîæíîñòü íåòî÷íîñòåé è òåõíè÷åñêèõ èçìåíåíèé
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CAP 279161/34452/2/8230 · HD