STIEBEL ELTRON LWZ 70 E Instruction Manual

OPERATION AND INSTALLATION
Central ventilation unit with heat recovery
» LWZ70E

2| LWZ70E www.stiebel-eltron.com
CONTENTS | SPECIAL INFORMATION
SPECIAL INFORMATION
OPERATION
1. General information �����������������������������������������3
1.1 Safety instructions����������������������������������������������� 3
1.2 Other symbols in this documentation ����������������������� 3
1.3 Units of measurement ������������������������������������������ 3
1.4 Standardised output data�������������������������������������� 3
2. Safety����������������������������������������������������������3
2.1 Intended use������������������������������������������������������ 3
2.2 General safety instructions ������������������������������������ 4
2.3 Test symbols ������������������������������������������������������ 4
3. Appliance description ���������������������������������������4
4. Settings �������������������������������������������������������4
4.1 Remote control��������������������������������������������������� 4
4.2 User interface on the appliance������������������������������� 4
4.3 Switching the appliance on������������������������������������ 5
4.4 Switching off the appliance������������������������������������ 5
4.5 Standard mode��������������������������������������������������� 6
5. Maintenance, cleaning and care����������������������������7
5.1 Replacement filter ����������������������������������������������� 7
5.2 Cleaning filters ��������������������������������������������������� 7
6. Troubleshooting ����������������������������������������������8
6.1 Fault analysis ����������������������������������������������������� 8
6.2 Fault code ��������������������������������������������������������� 8
INSTALLATION
7. Safety����������������������������������������������������������9
7.1 General safety instructions ������������������������������������ 9
7.2 Instructions, standards and regulations �������������������� 9
7.3 Operation of the appliance in buildings with
combustion equipment ����������������������������������������� 9
8. Appliance description ������������������������������������� 10
8.1 Standard delivery����������������������������������������������� 10
8.2 Required accessories ������������������������������������������ 10
8.3 Further accessories��������������������������������������������� 10
9. Preparations ������������������������������������������������ 10
9.1 Installation site�������������������������������������������������� 10
9.2 Transport ��������������������������������������������������������� 10
10. Installation�������������������������������������������������� 10
10.1 Mounting the appliance ��������������������������������������� 10
10.2 Connecting the condensate drain ��������������������������� 11
10.3 Connecting air ducts ������������������������������������������� 11
10.4 Power supply ���������������������������������������������������� 12
11. Commissioning ��������������������������������������������� 12
11.1 Initial start-up��������������������������������������������������� 12
11.2 Shutdown �������������������������������������������������������� 12
11.3 Recommissioning����������������������������������������������� 12
12. Settings ����������������������������������������������������� 13
12.1 Settings menu��������������������������������������������������� 13
12.2 Read-out menu ������������������������������������������������� 14
12.3 Service menu ���������������������������������������������������� 15
12.4 Restoring factory settings������������������������������������� 16
SPECIAL INFORMATION
- The appliance may be used by children aged8
and up and persons with reduced physical, sen-
sory or mental capabilities or a lack of experience
and know-how, provided that they are supervised
or they have been instructed on how to use the
appliance safely and have understood the result-
ing risks. Children must never play with the ap-
pliance. Children must never clean the appliance
or perform user maintenance unless they are
supervised.
- The power cable must only be replaced (for ex-
ample if damaged) by qualified contractors au-
thorised by the manufacturer.
- Secure the appliance as described in chapter "In-
stallation/ Installation".
13. Maintenance ������������������������������������������������ 16
14. Troubleshooting �������������������������������������������� 18
15. Specification ������������������������������������������������ 19
15.1 Dimensions and connections��������������������������������� 19
15.2 Standard circuit ������������������������������������������������� 20
15.3 Wiring diagram ������������������������������������������������� 21
15.4 Fan diagram ����������������������������������������������������� 22
15.5 Data table �������������������������������������������������������� 23
GUARANTEE
ENVIRONMENT AND RECYCLING

OPERATION
General information
ENGLISH
www.stiebel-eltron.com LWZ70E | 3
OPERATION
1. General information
The chapters "Special Information" and "Operation" are intended
for both the user and qualified contractors.
The chapter "Installation" is intended for qualified contractors.
Note
Read these instructions carefully before using the appli-
ance and retain them for future reference.
Pass on the instructions to any new user where appro-
priate.
1.1 Safety instructions
1.1.1 Structure of safety instructions
!
KEYWORD Type of risk
Here, possible consequences are listed that may result
from failure to observe the safety instructions.
 Steps to prevent the risk are listed.
1.1.2 Symbols, type of risk
Symbol Type of risk
Injury
Electrocution
Burns
(burns, scalding)
1.1.3 Keywords
KEYWORD Meaning
DANGER Failure to observe this information will result in serious
injury or death.
WARNING Failure to observe this information may result in serious
injury or death.
CAUTION Failure to observe this information may result in non-seri-
ous or minor injury.
1.2 Other symbols in this documentation
Note
General information is identified by the adjacent symbol.
 Read these texts carefully.
Symbol Meaning
Material losses
(appliance damage, consequential losses and environmen-
tal pollution)
Symbol Meaning
Appliance disposal
 This symbol indicates that you have to do something. The ac-
tion you need to take is described step by step.
1.3 Units of measurement
Note
All measurements are given in mm unless stated oth-
erwise.
1.4 Standardised output data
Explanations to determine and interpret the specified standardised
output data
1.4.1 Standard: DINEN 13141-7
The output data specifically mentioned in text, diagrams and
technical datasheets has been determined in line with the test
conditions described in the standard shown in the heading of
this chapter.
Generally, these standardised test conditions will not fully meet
the conditions found at the installation site of the system user.
Depending on the chosen test method and the extent to which
the selected method deviates from the conditions described in the
standard shown in the heading of this chapter, any deviations can
have a considerable impact. Further factors that have an influence
on the test values are the measuring equipment, the system con-
figuration, the age of the system and the flow rates.
A confirmation of the specified output data can only be obtained
if the conditions applicable to the relevant test match those of the
standard shown in the heading of this chapter.
2. Safety
2.1 Intended use
The appliance is designed as a mechanical ventilation unit with
centralised supply air and extract air routing.
This appliance is intended for domestic use. It can be used safely
by untrained persons. The appliance can also be used in a non-do-
mestic environment, e.g.in a small business, as long as it is used
in the same way.
Any other use beyond that described shall be deemed inappropri-
ate. Observation of these instructions and of instructions for any
accessories used is also part of the correct use of this appliance.
It is deemed inappropriate to:
- 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.
Never adjust the setting of supply and extract air valves inside the
rooms. These have been set up by a qualified contractor during
commissioning.
!
!

OPERATION
Appliance description
4| LWZ70E www.stiebel-eltron.com
2.2 General safety instructions
!
WARNING Injury
The appliance may be used by children aged 8 and up and
persons with reduced physical, sensory or mental capa-
bilities or a lack of experience and know-how, provided
that they are supervised or they have been instructed on
how to use the appliance safely and have understood
the resulting risks. Children must never play with the
appliance. Children must never clean the appliance or
perform user maintenance unless they are supervised.
Note
Trouble-free operation of the appliance is only possible
with a closed appliance cover.
2.3 Test symbols
See type plate on the appliance.
3. Appliance description
The appliance draws in outdoor air with a fan. A second fan draws
in extract air from rooms in the home with odour or humidity loads
(kitchen, bathroom and WC). Extract air and outdoor air are routed
through separate ducts. Extract air and outdoor air are filtered
by separate filters.
Both air streams are routed through a cross-countercurrent heat
exchanger. The extract air gives off heat, which is transferred to
the outdoor air. This means that the extracted stale indoor air
heats the fresh clean outdoor air, saving energy and routing fresh
air into the interior.
You can use the user interface to infinitely adjust the air flow rates.
The appliance has a filter service indicator, as well as an optional
filter service indicator at the stage switch.
The control unit has three fan stages. The air flow rate is preset
for each fan stage by the qualified contractor. Constant flow rate
control ensures that the air flow rates of the supply air and extract
air are achieved irrespective of the duct pressure.
Fan stage
Humidity protection ventilation: This fan stage prevents mould
formation using the factory-set air flow rate of 50m³/h. Alter-
natively, the contractor can set an air flow rate of 0m³/h when
commissioning the appliance. In such a case, no humidity pro-
tection is provided.
Fan stage1 should be seen as background ventilation, to be se-
lected when going away for example.
Fan stage2 is recommended for standard ventilation.
Fan stage3 is recommended as intensive ventilation, to tempo-
rarily increase the air flow rate for load peaks (e.g. as a party
stage).
Frost protection
On account of the high heat recovery level, low outdoor tempera-
tures result in the extract air being cooled down so severely that
any condensate that is created in the process may freeze. Frost
protection ensures that the extract air side of the heat exchanger
cannot freeze. Depending on the outdoor air temperature and
the pressure drop at the heat exchanger, the balance between
the supply air flow and the extract air flow is disrupted, thus pre-
venting freezing. The supply air fan may also, for short periods,
be switched OFF at very low outdoor temperatures. Preheating
the outdoor air by using an electric preheating coil or by means
of a geothermal heat exchanger, for example, can prevent this
imbalance or can prevent the supply air fan shutting down.
Bypass function
The appliance is equipped with a bypass function. If the conditions
for the bypass function are met, the ventilation air fan is switched
off. This enables warm indoor air to be transported away. Once
the conditions for the bypass function are no longer being met,
the ventilation air fan is switched back on.
The bypass function can be adjusted in the settings menu using
parameters 05, 06 and 07.
Conditions
Bypass function
active
The outside temperature is higher than 10°C and lower
than the room temperature, and the room temperature is
higher than the bypass temperature set in parameter 05.
Bypass function
inactive
The outside temperature is lower than 10°C.
The outside temperature is at least 0.5°C higher than the
room temperature.
The room temperature is lower than the bypass tem-
perature reduced by the bypass hysteresis. The bypass
temperature is set in parameter 05. The bypass hysteresis
is set in parameter 06.
4. Settings
Note
User operations are restricted to switching the appliance
ON and OFF. The basic settings are set by your qualified
contractor when commissioning the appliance.
4.1 Remote control
Observe the operating and installation instructions for the relevant
remote control (see chapter "Appliance description/ Required ac-
cessories" or "Appliance description / Other accessories").
4.2 User interface on the appliance
The appliance has a user interface with display. This enables
air flow rates to be variably adjusted or operating details to be
checked.
D0000044898
1 2 3 4 5
1 Menu key
2 Minus key
3 LCD
4 Plus key
5 R key
You can access and change settings using the four keys (menu,
plus, minus, R).

OPERATION
Settings
ENGLISH
www.stiebel-eltron.com LWZ70E | 5
When the mains power is switched on, all available symbols are
displayed for two seconds. The backlight is also switched on for
60 seconds.
If one of the keys is pressed, the display is illuminated for 30
seconds.
If no keys are pressed and/or if no blocking fault occurs, standard
mode is displayed.
When the menu key is pressed, you can use the plus or minus key
to choose between three different sub-menus:
- Settings menu (SET)
- Read-out menu (READ)
- Service menu (SERV)
With the R key, you can exit any selected menu and return to
standard mode.
To switch on the display backlight without changing anything in
the menu, press the R key briefly (less than 5 seconds).
Button Key function
Menu Open menu; open sub-menu; enable parameter for value change;
confirm value change
- Scroll; adjust value; switch appliance on or off from standard mode
(press and hold down for 5 seconds)
+ Scroll; adjust value
R One step back in the menu; reset adjusted value; filter reset (press
and hold down for 5 seconds); delete fault history
4.3 Switching the appliance on
26�04�15�0009
 Plug the appliance into a standard socket.
26�04�15�0011
All display symbols are shown for two seconds.
26�04�15�0029
The software version is displayed for two seconds.
D0000044916
The appliance then runs according to the stage switch setting. If
no stage switch is connected, the appliance always runs in fan
stage1.
Switching on via software
26�04�15�0032
If the appliance has been switched off via software, "OFF" is dis-
played.
5 s
26�04�15�0031
 Switch on the appliance by pressing the minusbutton for 5
seconds.
4.4 Switching off the appliance
Switching off via software
 Press and hold down the minus button for 5 seconds to
switch off the appliance.
The display shows "OFF".
5s
26�04�15�0048
Interrupting the power supply
26�04�15�0010
The display is now blank.

OPERATION
Settings
6| LWZ70E www.stiebel-eltron.com
WARNING Electrocution
Before working on the appliance, always isolate the
appliance from the power supply by first switching the
appliance off via the software and then unplugging it
from the mains.
4.5 Standard mode
In standard mode, the display shows up to four different pieces of
information (operating modes and values) simultaneously.
D0000044913
1 Indication of the fan stage, indication of connected
appliances
2 Indication of the air flow rate
3 Message text, e.g. filter status text, triggering of external
switching contact, etc.
4 Fault symbol
4.5.1 Fan stage
D0000044914
A fan symbol is displayed when the supply air fan and the extract
air fan rotate. The fan symbol is not visible when the fans are at
a standstill.
The number after the fan symbol indicates the fan stage.
Fan stage
indicator
Description
The supply air and extract air fans generate an air flow rate of
50m³/h or stop. This depends on the setting of parameter 01.
This fan stage cannot be enabled with a 3-stage switch. This fan
stage prevents mould formation using the factory-set air flow
rate of 50m³/h.
The supply air and extract air fans rotate according to stage1
of the stage switch. The air flow rate depends on the parameter
02 setting.
The supply air and extract air fans rotate according to stage 2
of the stage switch. The air flow rate depends on the parameter
03 setting.
The supply air and extract air fans rotate according to stage 3
of the stage switch. The air flow rate depends on the parameter
04 setting.
A number of appliances of this type have been connected. The
supply air and extract air fans rotate according to the fan stage
selected at the master appliance. If the appliance is connected
in a cascade, the slave number of the appliance is displayed.
4.5.2 Indication of the air flow rate
D0000044915
The selected air flow rate of the supply air and extract air fans is
displayed.
If the air flow rates of the supply air and extract air fans differ,
e.g. when an external switching contact is used, the highest air
flow rate is always displayed.
If you switch the appliance off using the programming unit, the
text "OFF" appears.
4.5.3 Message texts in standard mode
D0000044921
At this point on the display, a message text may appear. The mes-
sage text "FILTER" always takes priority over other message texts.
Message text Description
FILTER
If FILTER is displayed, the filter must be cleaned or re-
placed.
V1 or V2
If V1 or V2 is displayed, one of the 0-10V inputs is ena-
bled.
Only when using connection X1:
Message text Description
Slave 1, Slave 2, etc. Master appliance:
Slave appliance:
With connected appliances, the message text indicates
which appliance is the "Slave 1" to "Slave 9". The default
display for fan operation is indicated on the master
appliance.

OPERATION
Maintenance, cleaning and care
ENGLISH
www.stiebel-eltron.com LWZ70E | 7
5. Maintenance, cleaning and care
Maintenance by the user is limited to filter cleaning or replacement
required at certain intervals.
5.1 Replacement filter
Product desig-
nation
Part number Description
FMSLWZ 70 222446 Filter mat G3;
10pce per packing unit
FMSF7-2 70 227660 Fine filter F7;
2pce per packing unit
5.2 Cleaning filters
Filters must be cleaned when "FILTER" is displayed.
D0000044917
 Replace filters annually.
Never operate the appliance without filters.
Cleaning or replacing filters
> 5 s
D0000041945
 Press and hold down the minus button for 5 seconds to
switch off the appliance.
 Remove the filter flaps.
D0000041946
1
2
1 Extract air filter
2 Supply air filter
 Extract the supply air and extract air filters. Make a note of
how the filters were fitted.
26�04�15�0015
 Clean the filters, e.g. with a vacuum cleaner.
D0000041947
 Push the cleaned or new filter into the appliance.
> 5 s
D0000041948
 Assemble the two filter flaps.
 Switch on the appliance by pressing the minusbutton for 5
seconds.
5s
1
2 3
D0000044937
 After cleaning or replacing the filters, hold down the R key
for 5 seconds to reset the filter display.

OPERATION
Troubleshooting
8| LWZ70E www.stiebel-eltron.com
To confirm that the filters have been reset, the text "FILTER" will
flash briefly. Even if the message "FILTER" has not yet been dis-
played, you can reset the filter message. The counter is then reset
to zero.
Once the filter has been reset, the text "FILTER" disappears and
standard mode is displayed again.
6. Troubleshooting
6.1 Fault analysis
D0000044931
If the appliance detects a fault, a flashing fault symbol (spanner)
is displayed, possibly together with a fault code. The appliance
differentiates between a fault, where the appliance continues to
operate with limited functionality, and a blocking fault, where both
fans are stopped. In the event of a blocking fault, the settings and
read-out menus are also switched off and access is restricted to
the service menu.
The appliance remains in this fault condition until the problem has
been resolved. The appliance then resets itself (auto reset) and
standard mode is displayed again.
6.2 Fault code
Non-blocking fault
D0000044923
If the appliance detects a non-blocking fault code, it continues to
operate with limited functionality. Non-blocking faults are dis-
played with the fault symbol (spanner).
Blocking fault
D0000036353
If the appliance detects a blocking fault code, it stops. The per-
manently illuminated display shows the fault symbol (spanner)
together with a fault code.
 Notify a qualified contractor, who can correct the fault.
A blocking fault cannot be resolved by briefly disconnecting the
appliance from the power supply. The fault itself must first be
rectified.
If you cannot remedy the fault, notify your qualified contractor.
To facilitate and speed up your request, provide the number from
the type plate (000000-0000-000000). The type plate is located on
the appliance cover.

ENGLISH
www.stiebel-eltron.com LWZ70E | 9
INSTALLATION
Safety
INSTALLATION
7. Safety
Only a qualified contractor should carry out installation, commis-
sioning, maintenance and repair of the appliance.
7.1 General safety instructions
We guarantee trouble-free function and operational reliability only
if original accessories and spare parts intended for the appliance
are used.
7.2 Instructions, standards and regulations
Note
Observe all applicable national and regional regulations
and instructions.
7.3 Operation of the appliance in buildings with
combustion equipment
If the building contains combustion equipment (tiled stoves, fire-
places, etc.), the responsible flue gas inspector must be consulted
in the planning phase. The flue gas inspector assesses whether all
statutory regulations are being observed. Here, a differentiation
is made between balanced and open flue combustion equipment.
For simultaneous operation of combustion equipment and a me-
chanical ventilation system, we recommend choosing approved
room sealed combustion equipment (in Germany, DIBt approval).
7.3.1 Room sealed combustion equipment
In conjunction with room sealed combustion equipment, no addi-
tional precautions are generally required. Assessment is carried
out by the flue gas inspector.
7.3.2 Open flue combustion equipment
!
WARNING INJURY
If open flue combustion equipment is operated with the
mechanical ventilation system, tested safety equipment
must be installed. The combustion equipment must also
have a separate combustion air supply.
With open flue combustion equipment, a differentiation must be
made between alternate and simultaneous operation of the ven-
tilation system and combustion equipment.
Alternate operation
Operation on alternate sides means that, when the combustion
equipment is commissioned, the mechanical ventilation system is
switched off and/or cannot be started.
Simultaneous operation
!
WARNING INJURY
To prevent any flue gas escaping into the installation
room, it is necessary to ensure that sufficient combustion
air is supplied or that the negative pressure in room
where the stove is installed is not greater than 4 Pa.
Tested safety equipment must be installed to monitor the
chimney draught (differential pressure monitoring) and
to switch off the ventilation unit in the event of a fault.
Connect the safety equipment according to the chapter "Instal-
lation/ Electrical connection/ Connecting safety equipment for
stove/fireplace operation".
The equipment for differential pressure monitoring should fulfil
the following requirements:
- Monitoring of the differential pressure between the connec-
tion piece to the chimney and the room where the combus-
tion equipment is installed.
- Possibility of matching the shutdown value for the differential
pressure to the minimum draught requirement for the com-
bustion equipment.
- Floating contact to switch off ventilation.
- Optional connection of a temperature capturing device so
that differential pressure monitoring is only enabled when
the combustion equipment is in operation and so that un-
wanted shutdowns due to environmental influences can be
avoided.
Note
Differential pressure switches that use the pressure
differential between the outdoor air pressure and the
pressure in the room where the combustion equipment
is sited as a response criterion are not suitable.
The mechanical ventilation system is switched off when the safety
equipment responds.
Note
The maximum available external pressure (see chapter
"Specification/ Data table") must not be exceeded.

10 | LWZ70E www.stiebel-eltron.com
INSTALLATION
Appliance description
8. Appliance description
8.1 Standard delivery
The following are delivered with the appliance:
- Wall mounting bracket set (2mounting brackets, 3protec-
tive caps, 1rubber strip, 2rubber rings, 1 set of installation
instructions)
- PVC condensate drain (1x1.5” threaded plastic nut, 1 sealing
ring, 1 PVC glued joint)
- Approx. 90 cm long cable for connecting a remote control
8.2 Required accessories
- Hardwired remote control used to control the air flow rates
preset in three stages. Our range of accessories includes re-
mote control units with additional functions.
8.3 Further accessories
- Preheater coil
- You can obtain ventilation pipes, extract air and supply air
valves and similar accessories from us.
9. Preparations
9.1 Installation site
The appliance can be mounted on the wall with the wall mounting
bracket set supplied.
!
Material losses
For vibration-free mounting, a solid wall with a minimum
mass of 200kg/m2is required. A plaster board or metal
framed wall is inadequate. Additional measures such as
a double skin or additional supports would be needed
in such cases.
Ensure the equipment is level after installation.
The installation site must have an adequate condensate drain with
stench trap and a fall for the condensate.
The installation site must be free from the risk of frost.
Minimum clearances
≥300
≥300
D0000041883
9.2 Transport
To protect the appliance against damage, you should transport it
to the installation room inside its original packaging.
10. Installation
10.1 Mounting the appliance
10 mm
26�04�15�0078
 Undo the two top crosshead screws on the back of the
appliance.
 Secure one of the two rails to the appliance with screws.
!
Material losses
 Check whether the wall can bear the weight of the
appliance.
 Use appropriate rawl plugs and screws suitable for
the wall structure to attach the rail.
 Mount the second rail on the wall as a retainer. To avoid
sound transmission, place the washers supplied between the
wall and the rail.
 Affix the spacers supplied to the back of the appliance.

ENGLISH
www.stiebel-eltron.com LWZ70E | 11
INSTALLATION
Installation
26�04�15�0079
 Place the rubber strips supplied on the rail mounted on the
wall. The rubber strip helps provide sound insulation.
 Fit the appliance so that the two rails interlock.
10.2 Connecting the condensate drain
!
Material losses
Never kink the hose, to ensure the condensate drains
perfectly. The fall must be at least 10%. Ensure the device
is level after installation.
> 60
D0000041960
The condensate drain is routed through the floor plate. The con-
densate must drain away via the domestic sewer system.
 Secure the condensate drain connector supplied along with
the gasket and union nut to the condensate drain located un-
derneath the appliance.
You can fit the condensate drain pipe (bent if required) to this
condensate drain connector with a glued joint.
 Before connecting the condensate drain to the appliance,
pour water into the siphon to create a stench trap.
The condensate drain pipe must terminate below the water level
in the siphon. The condensate drain pipe must be immersed in
the water in the siphon by at least 60 mm.
10.3 Connecting air ducts
During installation, ensure that no metal swarf enters the
ductwork. However, should this still occur, you must remove this
material, otherwise the fans may be damaged.
External wall ducts
Supply outdoor air from a location where contamination (dust,
soot, odours, flue gas, exhaust air) is as low as possible.
When installing external wall ducts, prevent any short circuit be-
tween the air intake and the air discharge.
Silencers
Install a silencer in both the supply air and extract air ducts. We
recommend installing additional silencers if required to avoid
sound transmission.
If a room with a high noise level must be ventilated, install addi-
tional silencers upstream of this room to reduce sound transmis-
sion to adjacent rooms.
Aspects such as carried voices and impact sound must also be
taken into consideration in the case of ducts embedded in con-
crete. Carried voices should be avoided by designing the duct
with separate branches to the extract air and supply air valves.
If required, insulate the supply air ducts, e.g. if they are outside
the insulated wall panel.
Overflow apertures
In living rooms and bedrooms, air is only blown in. Air is only
extracted from rooms where odours and moisture are generated.
Ventilation grilles must be installed in internal doors or walls,
or the air gap beneath the door must be increased to ≥ 8 mm to
ensure an unobstructed air flow.
Insulation against condensation
!
Material losses
When warm air meets cold surfaces, condensation can
result.
 For outdoor air and exhaust air ducts, use va-
pour-proof thermally insulated pipes.
 If you use uninsulated pipes and moulded parts for
this pipework, ensure that they are adequately insu-
lated.
 Insulate the supply air and extract air ducts if they
are routed through unheated rooms.
The extract air duct does not require a control valve, because the
necessary air flow rates are controlled by the appliance itself.

12 | LWZ70E www.stiebel-eltron.com
INSTALLATION
Commissioning
10.4 Power supply
WARNING Electrocution
Carry out all electrical connection and installation work
in accordance with national and regional regulations.
WARNING Electrocution
Before connecting the appliance to the mains power sup-
ply, isolate all power cables. Isolation from the mains
power supply must be carried out with a contact sep-
aration of at least 3mm, e.g. by means of omnipolar
isolators.
You can connect the appliance to a standard socket with the plug
fitted to the appliance.
12
D0000041968
1
2
3
4
5
1 Power cable
2 Two-pole screw connection (only suitable for low voltage)
3 Modular plug-in connection (RJ12, only suitable for low
voltage)
4 Service connection
5 Entry electrical cables
Connecting safety equipment for stove/fireplace operation so
that the safety equipment can interrupt the power supply
 Connect the safety equipment in accordance with the dia-
gram in chapter "Specification/ Standard circuit".
11. Commissioning
11.1 Initial start-up
Setting the air flow rate
Output and energy consumption of the appliance depend on the
pressure drop in the duct system and the resistance of the filters.
Fan stage Air flow rate
m³/h 0
50: Moisture protection ventilation
This fan stage prevents mould formation using the
factory-set air flow rate of 50m³/h.
m³/h must be lower than for stage 2
m³/h must be lower than for stage 3
m³/h 50 - 180
The air flow rate of the higher fan stage is automatically selected
if one of the above conditions is not met.
11.2 Shutdown
Even during longer periods away from home, we recommended
that the equipment should be allowed, via the remote control,
to run at switch position1. If you nevertheless need to take the
appliance out of use for an extended period, switch it off via the
user interface and unplug it from the mains to isolate it from the
power supply.
 Clean or replace filters.
11.3 Recommissioning
 Check whether filters are fitted in the appliance. Never start
the appliance without filters.
 Check whether the condensate drain is damaged or kinked.

ENGLISH
www.stiebel-eltron.com LWZ70E | 13
INSTALLATION
Settings
12. Settings
12.1 Settings menu
For optimum appliance function, you can change parameters used
to adapt the appliance to the actual installation. Some parameter
settings such as the air flow rates have been set out in the technical
details appertaining your individual building.
Note
Changes to settings not described may only be made by
agreement with the manufacturer. Incorrect settings may
impair the correct appliance function.
12.1.1 How to set parameters
 Press menu in standard mode.
The settings menu is displayed ("SET").
26�04�15�0064
Enabling the settings menu
 Press menu again to enable the settings menu.
D0000044922
Selecting parameters
 Use the plus or minus key to select the parameter you want
to set.
D0000044924
1 2
1 Parameter number
2 Parameter value
Parameter change
 Press menu.
D0000044926
 The parameter value starts to flash.
D0000044929
 Use plus or minus to change the parameter value.
Discarding a parameter change
 If you do not want to save the amended parameter value,
press the R key.
D0000044927
Confirm parameter value
D0000044928
 If you do want to save the amended parameter value, press
the R key.
Note
To change other parameters, repeat the steps described
from "Selecting parameters". If you do not want to change
any more parameters, press R. This brings you back to
normal operating mode.

14 | LWZ70E www.stiebel-eltron.com
INSTALLATION
Settings
12.1.2 List of parameters in the settings menu
Parameter Description Unit Factory
setting
Setting range Step
size
Display text and
symbols
01
Air flow rate of stage
m3/h 50 0
50: Moisture protection ventilation
02 Air flow rate of stage 1 m3/h 75 50- 180 5
03 Air flow rate of stage 2 m3/h 100 50 - 180 5
04 Air flow rate of stage 3 m3/h 150 50-180 5
05 Bypass temperature °C 22 15 - 35 0.5
BYPASS
06 Bypass hysteresis °C 2 0 - 5 0.5
BY HYS
07 Bypass function 0 0 (Automatic function)
BYPASS
1 (bypass function permanently inactive)
2 (bypass function permanently active)
08 BUS address 0 0 - 9 (0 = master) BUSADR
09 Introduction of an additional ex-
tract air flow.
OFF This parameter is not relevant for you. As default, this
parameter must remain OFF for this appliance.
CV+WTW
10 Pressure imbalance permissible ON OFF (Air flow rate for supply/extract air the same)
ON (Pressure imbalance permissible)
11 Fixed pressure imbalance m3/h 0 -50 - 50 1
12 Preheating coil connected OFF ON (Preheater coil connected)
OFF (No preheater coil)
13 - 29 no function
30 Humidity sensor OFF OFF (Humidity sensor switched off)
ON (Humidity sensor switched on)
31 Humidity sensor sensitivity 0 2 (sensitive) to -2 (least sensitive)
12.2 Read-out menu
With the read-out menu, you can call up some values for more
detailed information on the function of the appliance. Values and
settings cannot be changed in the read-out menu.
26�04�15�0064
 Press menu in standard mode.
The settings menu is displayed ("SET").
26�04�15�0071
 Press plus or minus to switch to the read-out menu.
26�04�15�0072
 Press Menu to enable the read-out menu.
26�04�15�0073
1 2
 Use plus or minus in the read-out menu to move to the re-
quired parameter.
Read-out menu Description of the actual value Unit
01 Room temperature °C
02 Outside temperature (captured by the outside
temperature sensor)
oC
03 Bypass status (ON = Bypass function active, OFF =
Bypass function not active)
04 Frost protection status (ON = Frost protection en-
abled, OFF = Frost protection disabled)

ENGLISH
www.stiebel-eltron.com LWZ70E | 15
INSTALLATION
Settings
2 x
D0000044932
 Press R twice to return to standard mode.
If no key is pressed for 5 minutes, the appliance returns automat-
ically to standard mode.
12.3 Service menu
In the service menu, you can view the last 10 fault messages.
In the case of blocking faults, the settings menu and the read-out
menu are blocked and only the service menu can be accessed.
Pressing menu opens the service menu.
Viewing the service menu
26�04�15�0064
 Press menu in standard mode. The settings menu is
displayed.
26�04�15�0057
 Press plus or minus to switch to the read-out menu.
26�04�15�0058
12
1 Fault message number
2 Fault code
 Press the menu button to enable the service menu.
You can use plus and minus to scroll through the read-out menu.
Indication "No fault message"
26�04�15�0056
Current fault message (fault symbol on the display)
For fault messages with a cause that has not yet been eliminated,
the fault symbol (spanner) appears.
26�04�15�0075
Resolved fault message (no fault symbol on the display)
For fault messages with a caused that has been eliminated, the
fault symbol (spanner) does not appear.
26�04�15�0076
Back to standard mode
2 x
D0000044932
 Press R twice to return to standard mode.
Deleting fault messages
You can delete all fault messages by holding down R for five sec-
onds. This is only possible if there are no active faults.

16 | LWZ70E www.stiebel-eltron.com
INSTALLATION
Maintenance
12.4 Restoring factory settings
It is possible to reset all changed settings simultaneously to factory
settings.
All changed settings revert back to their factory default settings;
all message/fault codes are also deleted from the service menu.
D0000044930
 Press plus and minus simultaneously and hold down for 10
seconds.
All display symbols light up for three seconds. The appliance is
then in standard mode.
13. Maintenance
WARNING Electrocution
In the event of damage to the power cable this must
always be replaced by a qualified contractor authorised
by the manufacturer, using original spare parts.
Maintenance by the qualified contractor includes the cleaning of
the cross-countercurrent heat exchanger and the fans.
Subject to runtime, this maintenance work should be carried out
every 3 years.
 Switch off the appliance by pressing the minus key for
5seconds.
 Disconnect the power supply.
 Remove the filter flaps.
 Extract the filters. Make a note of how the filters were fitted.
2x
D0000041949
 Remove the front cover.
D0000041950
 Remove the display.
D0000041951
 Pull the insert on which the control PCB is fitted out of the
appliance.
 Disconnect all plugs on the control PCB that are connected to
plug-in connections at the top of the appliance.
 Remove the earth wire from the appliance body.
D0000041952
 Remove the heat exchanger from the appliance. Avoid dam-
aging the foam parts in the appliance.

ENGLISH
www.stiebel-eltron.com LWZ70E | 17
INSTALLATION
Maintenance
26�04�15�0047
 Use a commercially available vacuum cleaner to remove dust
and other loose dirt particles from the intake and discharge
surfaces.
 If required, clean the heat exchanger with warm water
(max.55 °C) and a commercially available detergent. Never
use solvents.
 Afterwards flush the heat exchanger with water.
D0000041953
 Extract the fan unit from the appliance.
D0000041954
 Remove the fans.
 Clean the fans with a soft brush.
 Do not move the pressure compensation weights.
 Reinstall the fans.
 Push the complete fan unit back into the appliance.
 Reconnect the fan cables to the PCB. Observe the label in
the appliance to establish the correct position for the plug-in
connections.
 Slide the insert with the control PCB into the appliance.
 Install the display.
 Reconnect all cables disconnected before cleaning, to their
original position.
 Slide the heat exchanger back into the appliance.
 Fit the front cover.
 Insert the filters, respectively with their clean sides facing
towards the heat exchanger.
 Assemble the filter flaps.
 Switch on the power supply.
 Switch on the appliance using the user interface by holding
down minus for 5 seconds.
 After cleaning the filter or installing a new filter, reset the fil-
ter status indicator by holding down R for 5 seconds.
Cleaning the air ducts
Air ducts should be checked and possibly cleaned at regular in-
tervals. Releasing the air ducts from the appliance or over the
extract air and supply air valves enables inspection and cleaning.

18 | LWZ70E www.stiebel-eltron.com
INSTALLATION
Troubleshooting
14. Troubleshooting
Fault
code
Block-
ing
fault
Cause Appliance be-
haviour
Measure
E104 Yes The extract air
fan is faulty.
Both fans are
switched off. The
preheating coil, if
present, is switched
off. Restarting
occurs every 5 min-
utes.
Isolate the appliance
from the power sup-
ply. Replace the ex-
tract air fan. Switch
on the power supply
to the appliance
again. The fault is
reset automatically.
Check the cabling.
E105 Yes The supply air
fan is faulty.
Both fans are
switched off. The
preheating coil, if
present, is switched
off. The reheater
coil, if present,
is switched off.
Restarting occurs
every 5 minutes.
Isolate the appliance
from the power sup-
ply. Replace the sup-
ply air fan. Switch on
the power supply to
the appliance again.
The fault is reset
automatically. Check
the cabling.
E106 Yes The temper-
ature sensor
for capturing
the outside
temperature is
faulty.
Both fans are
switched off. The
preheating coil, if
present, is switched
off.
Isolate the appliance
from the power
supply. Replace the
outside temperature
sensor. Switch on the
power supply to the
appliance again. The
fault is reset auto-
matically.
E107 no The temper-
ature sensor
for capturing
the extract air
temperature is
faulty.
The bypass function
is switched off.
Isolate the appliance
from the power
supply. Replace the
room temperature
sensor.
E108 no If installed:
The tempera-
ture sensor in
the external
reheater coil
is faulty.
The reheater coil, if
present, is switched
off. The geothermal
heat exchanger, if
present, is switched
off.
Replace the temper-
ature sensor for the
outside temperature.
E111 no The humid-
ity sensor is
faulty.
The appliance is still
operating.
Isolate the appliance
from the power
supply. Replace the
humidity sensor.
E999 Yes The mi-
croswitches
on the control
PCB are not
set correctly.
The appliance does
not operate; the red
fault LEDs at the
stage switch are
also off.
Adjust the mi-
croswitches cor-
rectly.
Correct microswitch setting
X6
X4
X3
ON
D
D0000041967
 Check whether the microswitches on the control PCB are
set correctly (see diagram). If message E999 is nevertheless
displayed, replace the control PCB with a PCB of the correct
type.
Stage switch modular connector
If stage2 on a stage switch does not work, the modular connector
of the stage switch is not connected correctly.
 Disconnect one of the RJ plug-in connections to the stage
switch. Fit a new plug-in connection in the opposite
direction.

ENGLISH
www.stiebel-eltron.com LWZ70E | 19
INSTALLATION
Specication
15. Specification
15.1 Dimensions and connections
125168
248
600 45
145
560
79 75
213
77
77
213
302
g03
g04 g05
g06
d45
b01
D0000041882
LWZ70E
b01 Entry electrical
cables
d45 Condensate drain Diameter mm 13
g03 Outdoor air Nominal diameter DN 125
g04 Exhaust air Nominal diameter DN 125
g05 Extract air Nominal diameter DN 125
g06 inrushing air Nominal diameter DN 125

20 | LWZ70E www.stiebel-eltron.com
INSTALLATION
Specication
15.2 Standard circuit
L
N
PE
1/N/PE
230V ~50Hz
Lüftungsgerät
6 x 0,5 mm² max. 30 m
Schalter Kaminbetrieb
Ofen
Raum Druckanschluss
Differenzdruckcontroller für Feuerstätten
X2
ZLWZ 4S
24 V P (0V) 0 2 3 LED
24 V P (0V) 0 2 3 LED
FEZ
24 V P (0V) 0 2 3 LED
12104 115
FEQ
24 V P (0V) 0 2 3 LED
64
25 1
3-Stufen-Schalter
24 V
P (0V)
0
2
3
LED
3
2
1
D0000055737
3-Stufen-Schalter 3-stage switch
ZLWZ 4S 4-stage switch
FEQ Air quality sensor
FEZ Remote control
Lüftungsgerät Ventilation unit
Ofen Stove
Raum Room
Druckanschluss Pressure connection
Schalter Kaminbetrieb Switch, fireplace operation
Differenzdruckcontroller
für Feuerstätten
Differential pressure controller for combustion equipment