STIEBEL ELTRON LWZ 304 Integral Instruction Manual

OPERATION
Central ventilation unit with heat recovery
» LWZ304Integral
» LWZ304Trend
» LWZ404Trend

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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
2. Safety����������������������������������������������������������3
2.1 Intended use������������������������������������������������������ 3
2.2 General safety instructions ������������������������������������ 3
2.3 CE designation ��������������������������������������������������� 4
2.4 Test symbols ������������������������������������������������������ 4
3. Appliance description ���������������������������������������4
4. Operation �����������������������������������������������������4
4.1 Controls������������������������������������������������������������ 4
4.2 Operating modes ������������������������������������������������ 6
4.3 Favourites, quick access, function block �������������������� 7
4.4 Entering parameters �������������������������������������������� 8
4.5 Main menu�������������������������������������������������������� 8
 ACTUAL VALUES�������������������������������������������������� 8
 DIAGNOSIS �������������������������������������������������������� 9
 SYSTEM STATUS�������������������������������������������������� 9
 FAULT LIST��������������������������������������������������������� 9
 PROGRAMS ������������������������������������������������������� 9
 HEATING PROGRAM ��������������������������������������������� 9
 DHW PROGRAM ������������������������������������������������� 10
 FAN PROGRAM �������������������������������������������������� 10
 HOLIDAY PROGRAM �������������������������������������������� 10
 PARTY PROGRAM ����������������������������������������������� 10
 SETTINGS��������������������������������������������������������� 10
 HEATING ���������������������������������������������������������� 10
 DHW ��������������������������������������������������������������� 12
 VENTILATION ���������������������������������������������������� 12
 DRY HEATING PROGRAM�������������������������������������� 13
 COMMISSIONING ������������������������������������������������ 13
 TIME / DATE ������������������������������������������������������ 14
 CONTRACTOR ���������������������������������������������������� 14
5. Cleaning, care and maintenance ������������������������� 15
5.1 Replacing supply air and extract air filters���������������� 15
6. Troubleshooting �������������������������������������������� 16
6.1 Filter symbols appear������������������������������������������ 16
6.2 No hot water����������������������������������������������������� 16
6.3 The safety valve of the cold water supply line is
dripping ���������������������������������������������������������� 16
6.4 The fault symbol appears ������������������������������������� 16
6.5 The appliance leaks water ������������������������������������ 16
6.6 Condensate on the outside of the appliance or on the
air hoses���������������������������������������������������������� 16
6.7 Noise is emitted������������������������������������������������� 16
6.8 The required flow temperatures are not reached,
particularly during drying out ������������������������������� 16
6.9 The accommodation is always too cold �������������������� 16
6.10 The accommodation is always too hot ��������������������� 16
6.11 The accommodation is too cold in winter������������������ 17
6.12 The accommodation is too hot in winter������������������� 17
SPECIAL INFORMATION
- The appliance may be used by children aged8
and older and persons with reduced physical,
sensory or mental capabilities or a lack of ex-
perience 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 ap-
pliance 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.
- The appliance is pressurised. During the heat-up
process, expansion water will drip from the safety
valve.
- Regularly activate the safety valve to prevent
it from becoming blocked, e.g. by limescale
deposits.
6.13 The accommodation is too cold in spring and autumn � 17
6.14 The accommodation is too hot in spring and autumn �� 17
6.15 The accommodation is too hot in summer ���������������� 17
6.16 Air quality is too poor������������������������������������������ 17
6.17 The air in winter is too dry ����������������������������������� 17
6.18 Contact a qualified contractor�������������������������������� 17
7. Menu structure ��������������������������������������������� 18
CUSTOMER SERVICE AND GUARANTEE
ENVIRONMENT AND RECYCLING

OPERATION
General information
ENGLISH
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OPERATION
1. General information
This manual is intended for the appliance user and qualified con-
tractors.
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
Notes are bordered by horizontal lines above and below
the text. 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.
These symbols show you the software menu level (in
this example: level3).
1.3 Units of measurement
Note
All measurements are given in mm unless stated oth-
erwise.
2. Safety
2.1 Intended use
The appliance is a complete system with heat recovery for cen-
tralised ventilation and extraction, as well as for centralised DHW
heating and central heating.
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 inappro-
priate. Observation of these instructions is also part of the correct
use of this appliance.
2.2 General safety instructions
Operate the appliance only when fully installed and with all safety
equipment fitted. Check the supply air and extract air filters reg-
ularly for contamination.
Never adjust the setting of supply and extract air valves inside the
rooms. These have been adjusted during commissioning.
Never make any modifications to the internal equipment electrics
or controls.
!
WARNING Injury
The appliance may be used by children aged 8 and older
and persons with reduced physical, sensory or mental
capabilities or a lack of experience and know-how, pro-
vided that they are supervised or they have been in-
structed 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 ap-
pliance or perform user maintenance unless they are
supervised.
WARNING Electrocution
Never splash the appliance with water or other liquids.
WARNING Burns
There is a risk of scalding at outlet temperatures in ex-
cess of 43°C.
!
!

OPERATION
Appliance description
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Note
The appliance is pressurised. During the heat-up process,
expansion water will drip from the safety valve.
 If water continues to drip when heating is complet-
ed, please inform your qualified contractor.
!
WARNING Injury
If there is a radio or police announcement ordering win-
dows and doors to be kept closed, simply select fan stage
"0" (= fan off) for several hours.
The programming unit must be activated if the appliance
has been out of operation for a long time:
 Hold down "MENU" button for three seconds.
 If you have already navigated through the menu
tree, pressing MENU will return you to the default
display. If necessary you may have to press menu
several times.
 Slide your finger along the scroll wheel until you
reach the "VENTILATION STAGES" entry.
 Press "OK".
 Press "OK" again to adjust the "UNSCHEDULED
VENT." parameter.
 Set the "UNSCHEDULED VENT." parameter to 0 by
sliding your finger anti-clockwise over the scroll
wheel.
 Confirm with "OK".
 Set the "UNSCHED. VENT TIME STAGE 0" parameter
to a suitable value.
Note
Do not change any system-specific settings at the control
unit. Your qualified contractor has set the control unit
to match the local conditions for your building and your
individual requirements. The system-specific parameters
are protected by a code to prevent unintentional mod-
ifications.
The parameters that serve to adapt the appliance to your
personal requirements are not protected by a code.
2.3 CE designation
The CE designation shows that the appliance meets all essential
requirements according to the:
- Electromagnetic Compatibility Directive
- Low Voltage Directive
2.4 Test symbols
See type plate on the appliance.
3. Appliance description
Heat is recovered from the extract air by means of a highly efficient
cross-countercurrent heat exchanger and an air/water heat pump.
In addition, heat is extracted from the outdoor air. This energy,
efficiently made available by the heat pump, is channelled to the
central heating or DHW system. The cooled air is discharged out-
doors as exhaust air.
When the temperature is very low, or when there is a very high
heat demand, the appliance covers the residual heat demand by
means of an integral electric emergency/booster heater. With a
mono mode design, the electric emergency/booster heater is acti-
vated for emergency heating if the temperature reading falls below
the standard outside temperature, set as the dual mode point.
This ensures heating operation and the provision of high DHW
temperatures. In mono energetic mode, the electric emergency/
booster heater is activated as a booster heater.
The appliance is controlled by a weather-compensated control
unit.
Heat metering
The appliance is equipped with an integral heat meter. In the "AC-
TUAL VALUES" menu, the supplied amounts of heat are displayed.
4. Operation
4.1 Controls
WEDNESDAY 10 SEPT 14 10:23 H
OUTSIDE TEMPERATURE
DHW TEMPERATURE
27.0 °C
35.0 °C
28.0 °C
FLOW TEMPERATURE
DAY M ODE
26�04�01�0309
The programming unit enables you to change parameters and
to obtain information on the appliance operation. The appliance
can also be controlled when no programming unit is connected
or the connected one is faulty. The programming unit comprises
the scroll wheel, two keys and above these a display. The display
shows the current appliance status and provides messages as well
as information. The programming unit functions are accessed via
a menu tree. With the scroll wheel, you can navigate the menu
structure and change values.
4.1.1 Display
26�04�01�0292
WEDNESDAY 10 SEPT 14 10:23 H
OUTSIDE TEMPERATURE
DHW TEMPERATURE
27.0 °C
35.0 °C
28.0 °C
FLOW TEMPERATURE
DAY MODE
1
2
3
4
1 Date and time
2 Favourites
3 Operating mode
4 Appliance status symbols
The start screen is divided into four sections by horizontal lines.
The time and date are at the top. In the field below this, your fa-
vourites are displayed. Here, you can check up to three appliance
parameters at any time (see chapter "Favourites"). When you are
in the menu, the favourites display is no longer shown.

OPERATION
Operation
ENGLISH
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The third section provides information about the current operat-
ing mode and serves to control further functions, such as quick
access, function block. In the fourth section, at the bottom edge
of the display, pictorial symbols provide information about the
current system status.
You can adjust the contrast of the display and select the language
of the display texts in the "COMMISSIONING" menu.
4.1.2 Picture symbols in the display
At the lower edge of the display, symbols provide information
about the current appliance operating status. Up to eight symbols
can be displayed at once.
Filter change, top:
The extract air filter is contaminated. Please change the
extract air filter.
Filter change, bottom:
The supply air filter is contaminated. Please change the
supply air filter.
Filter change, top and bottom:
The filter change service intervals of the extract air and
the supply air filters have expired or the filters have be-
come contaminated prematurely. Please change the ex-
tract air and supply air filters.
Electric emergency/booster heater:
The electric emergency/booster heater has started up.
This occurs, for example, when the outside temperature
has fallen below the dual mode point.
Heating:
The heating symbol is displayed when the appliance is
in heating mode.
DHW heating:
This symbol tells you that the appliance is heating DHW.
Compressor:
The compressor symbol signals that the compressor is
running.
Evaporator defrost:
The evaporator is defrosting.
Switching program enabled:
If a switching program is enabled, this symbol is dis-
played.
Service:
A service is required. Please contact your qualified con-
tractor.
Ventilation stage:
For a limited period the appliance operates with a mod-
ified ventilation stage.
Heating circuit pump:
The pump symbol is displayed when a heating circuit
pump is running.
Heat-up:
This symbol shows when the drying heating program
runs.
Power-OFF:
This symbol lights up if the appliance has no enable signal
from the power supply utility.
4.1.3 Scroll wheel
26�04�01�0329
The scroll wheel consists of a touch-sensitive sensor. There is a
key to the left and another to the right of it. With the wheel and
the keys, you can control and check all the necessary appliance
functions.
Note
If you have gloves on, have wet hands or the program-
ming unit is damp, this impedes the recognition of your
touch and the execution of the action you require.
In the "COMMISSIONING" menu, your qualified contractor can set
the touch sensitivity using the "TOUCH SENSITIVITY" parameter.
Activation
The user interface is blocked to protect the appliance from acci-
dental incorrect adjustments.
WEDNESDAY 10 SEPT 14 10:23 H
OUTSIDE TEMPERATURE
DHW TEMPERATURE
14.0 °C
35.0 °C
18.0 °CFLOW TEMPER ATURE.
DAY MODE
TO ACTIVATE PLEASE
PRESS MENU FOR 3 S.
...
26�04�01�0292
 Touch the menu button for 3 seconds to enable the user
interface.
If the scroll wheel and keys are not used for 20minutes, the pro-
gramming unit is locked again. With the function block, you can
block the user interface for 60 seconds.

OPERATION
Operation
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Once the programming unit is activated, you have two adjustment
options:
- You can select operating modes with the scroll wheel.
- You can press "MENU" to continue navigating from there to a
specific appliance parameter.
Selection indicator
As you move through the menu and parameter levels, the selection
indicator shows your current position. Either a dark background
appears or the current list entry is highlighted by two lines, one
above and one below.
Circular movement
If you brush a finger clockwise along the recessed scroll wheel,
the highlighting field moves through the list of parameters either
to the right, or downwards if the parameters are arranged ver-
tically. With an anti-clockwise rotation, the highlighter moves to
the left or upwards.
Alongside navigation within the menu structure, the scroll wheel is
also used to set parameters. If you make a clockwise rotation, the
value is raised. With a circular movement anti-clockwise, values
are reduced.
Faster circular motions increase the step magnitude when chang-
ing parameters. Your qualified contractor can determine at what
speed of rotation the step magnitude changes, in the "COMMIS-
SIONING" menu using the "TOUCH ACCELERATION" parameter.
4.1.4 Menu key
The menu key has two functions. If you are on the default screen,
press "MENU" to enter the second level of the menu structure.
There, you have access to the appliance setting options, such as
the input of switching time programs.
If you are not in the highest menu level, tap the menu key to go
back one level.
Note
In the following sections of this document, the abbre-
viation "MENU" means you should touch the MENU key.
Note
Tap the keys only briefly to initiate the required action.
If you touch the menu and OK keys for too long, the pro-
gramming unit will not respond.
4.1.5 OK key
With one touch of the OK key, you confirm the selection of the
menu entry highlighted. This brings you into the menu tree on the
next menu level. If you are already at the parameter level, "OK"
saves the currently set parameter.
Example 1
In the third area on the start screen, the currently enabled oper-
ating mode is displayed, for example manual mode. If you want
to change to automatic mode, make a rotation until you reach
the required mode. Then confirm your selection with the OK key.
Only now does the appliance change to the new operating mode.
Example 2
The OK key is used to confirm parameter entries. The newly set
value is not saved until you press "OK".
Note
In the following sections of this document, the abbrevia-
tion "OK" means you should touch the OK key.
4.1.6 Acoustic signals
A click sound accompanies every user action. Example: A click
is heard every time "OK" and "MENU" are tapped. Furthermore,
the clicking accompanies every step along a menu list activated
by a rotation.
4.2 Operating modes
When the start screen is activated, the current operating mode
is displayed. If you want to select another operating mode, scroll
with the scroll wheel. This takes you through the list of possible
operating modes. The current choice (list entry) is shown in the
shaded selection field. To change the appliance to this new oper-
ating mode, confirm with"OK".
WEDNESDAY 10 SEPT 14 10:23 H
OUTSIDE TEMPERATURE
DHW TEMPERATURE
14.0 °C
35.0 °C
18.0 °CROOM TEMPERATURE
DAY MODE
26�04�01�0292
The appliance can operate in the following modes: Standby mode,
automatic mode, day mode, setback mode, DHW mode, manual
mode and emergency mode. In addition, you will find five further
setting options in this selection list: the favourites, the quick access
to ventilation stages, hotter/colder, direct line, and right at the end
of the list, the function block.
Since navigation to a new operating mode is always made from the
currently enabled mode, you may need to scroll in an anti-clock-
wise direction. All operating modes, apart from DHW mode, apply
to central heating, ventilation and DHW.
4.2.1 STANDBY
In standby mode, the appliance delivers the set standby values.
Generally, you will switch the appliance into minimum operation
with standby mode. The appliance runs in standby mode until
another operating mode is enabled.
4.2.2 AUTOMATIC
In automatic mode, the time programs set for central heating,
DHW and ventilation are implemented. Automatic mode is the
standard appliance setting. The heating flow temperature is reg-
ulated according to a weather-compensated heating curve. The
appliance runs in setback mode if no time programs are enabled.

OPERATION
Operation
ENGLISH
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4.2.3 DAY MODE
In day mode (generally while occupants are present in the house,
during the day), the heating system operates with the selected set
day values. Day mode does not influence DHW heating or venti-
lation.
4.2.4 SETBACK MODE
The appliance activity is reduced in setback mode, for example
at night time, or during the day when nobody is at home. In set-
back mode, the heating system is operated with the selected set
night values. Setback mode does not influence DHW heating or
ventilation.
4.2.5 DHW MODE
DHW mode is enabled in accordance with the set time programs.
For the current pair of switching times, the DHW set day value
is delivered. The central heating is switched off except for frost
protection. DHW operation does not influence ventilation.
4.2.6 MANUAL MODE
If manual mode is enabled, the set values selected for manual
mode are delivered. In manual mode, the heating flow tempera-
ture is not influenced by the outside temperature.
4.2.7 EMERGENCY MODE
If emergency mode is enabled, the "Compressor" heating stage
is skipped. It is heated by the electric emergency/booster heater.
The dual mode point is not taken into consideration. Using the
electric emergency/booster heater on its own for long periods
means high energy costs. If you activate emergency mode, the set
room temperatures from automatic mode are used. The switching
programs from automatic mode are also used.
4.3 Favourites, quick access, function block
As well as the operating modes, on the start screen you can also
select which parameters are always shown in the favourites list.
Additionally, you can influence the fan stage and temperature
via a quick link, jump straight to a parameter and enable the
function block.
4.3.1 FAVOURITES
You reach "FAVOURITES" if you run through the list of operating
modes on the default screen with the scroll wheel. Up to three
parameters are constantly shown on the display when the ap-
pliance is in operation. To select your favourites, navigate to the
required parameter. If the square at the end of the line is not filled
in, this parameter is not yet one of your favourites. Press "OK" to
change this. However, you can only select three favourites. You
may therefore have to disable one of your current favourites. Press
"OK" to disable.
4.3.2 VENTILATION STAGES
!
WARNING Injury
If there is a radio or police announcement ordering win-
dows and doors to be kept closed, simply select fan stage
"0" (= fan off) for several hours.
The programming unit must be activated if the appliance
has been out of operation for a long time:
 Hold down "MENU" button for three seconds.
 If you have already navigated through the menu
tree, pressing MENU will return you to the default
display. If necessary you may have to press menu
several times.
 Slide your finger along the scroll wheel until you
reach the "VENTILATION STAGES" entry.
 Press "OK".
 Press "OK" again to adjust the "UNSCHEDULED
VENT." parameter.
 Set the "UNSCHEDULED VENT." parameter to 0 by
sliding your finger anti-clockwise over the scroll
wheel.
 Confirm with "OK".
 Set the "UNSCHED. VENT TIME STAGE 0" parameter
to a suitable value.
With quick access option "VENTILATION STAGES", you reach the
setting area for the fan stage (see diagram below). Under "UN-
SCHEDULED VENT." enter the required value (0 to3). This setting is
valid for a limited time, which you set in the neighbouring menu
item, e.g. "UNSCHED. VENT TIMESTAGE 0". If you do not set a time,
the appliance adopts the saved parameter values.
26�04�01�0367
UNSCHED. VENT TIME STAGE 2
UNSCHEDULED VENT.
VENTILATION STAGES
02
4.3.3 HOTTER / COLDER
Here, you can change the set room temperatures for the heating
circuits and thereby raise or lower the heating curves.
4.3.4 DIRECT LINE
If you know the number of the required parameter (for example
P37), you can move straight there with the direct line.
 On the default screen, turn the scroll wheel until keyword
"DIRECT LINE" appears. Confirm with "OK". Select the number
of the required parameter. Confirm with "OK".
You can select parameters 01 to 89. To make the direct line easier
to use, the parameter designations are displayed along with their
numbers.

OPERATION
Operation
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4.3.5 FUNCTION BLOCK
If you select the "FUNCTION BLOCK" function, the programming
unit will be blocked for 60 seconds. During this time, you can
clean the programming unit without accidentally changing the
appliance settings. A counter appears on the screen that shows
the remaining blocking time in seconds.
4.4 Entering parameters
If you are on a menu level where you have the choice between
different parameters, the value of the parameter is shown as a
preview in addition to the current list position. Parameters are
changed by scrolling with the scroll wheel. To save the new value,
touch "OK". If you want to cancel the entry, press "MENU". The
parameter retains the previously saved value.
Note
If more than five minutes pass without any user activity,
rotation or tapping of "MENU" or "OK", the programming
unit display automatically jumps back to the default
screen. Recent parameter changes not yet been con-
firmed with "OK" will be lost. The parameters retain the
values previously saved.
Example 1
To enter set temperatures, a number surrounded by a circle ap-
pears on the display. This indicates that you can change the value
by turning the scroll wheel.
+
21.7
-
MAIN MENU
HEATING
ROOM TEMPERATURE DAY
°C
26�04�01�0347
ROOM TEMPERATURES HC1 HC
ROOM TEMPERATURE DAY
Example 2
To set holiday dates, a calendar page for the selected month ap-
pears.
DAY MONTH YEAR HOUR MINUTE
26�04�01�0300
Settings
HOLIDAY PROGRAM-PARTYHOLIDAY PROGRAM
HOLS BEGINNING
MON TUE WED THU FRI SAT SUN
02 03 04 05 06 07 08
09 10 11 12 13 14 15
16 17 18 19 20 21 22
23 24 25 26 27 28 29
01
30
Turning the scroll wheel displays the highlighter that you can then
move to the required date.
Example 3
Some parameters are selected via highlighted boxes. The positions
where the box is highlighted, i.e. coloured in black, are active. One
example is setting up favourites. With "OK" you can highlight the
box, or remove it if the item was already highlighted. For favour-
ites, up to three highlighted list entries can be selected in this way.
ROOM TEMPERATURE HC1
SET ROOM TEMPERATURE HC1
ROOM TEMPERATURE HC2
SET ROOM TEMPERATURE HC2
34.2 °C
26�04�01�0298
MAIN MENU
ACTUAL VALUES
ROOM TEMPERATURE
4.4.1 Contractor access
To prevent incorrect adjustments, some appliance parameters may
only be changed by qualified contractors. These parameters are
protected and can only be changed after entering a code.
0* **
26�04�01�0293
ENTER CODE
MAIN MENU
VENTILATIONVENTILATION
FAN STAGE VENT. AIR
4.5 Main menu
Note
Some menu items are protected by a code and can only
be accessed and adjusted by a qualified contractor.
 ACTUAL VALUES
26�04�01�0294
ACTUAL VALUES
MAIN MENU
DIAGNOSIS
PROGRAMS
SETTINGS
CONTR ACTOR
In the "ACTUAL VALUES" menu, actual values are displayed. See
the chapter "Menu structure" for a list of these.

OPERATION
Operation
ENGLISH
www.stiebel-eltron.com LWZ 304-404 Trend/LWZ 304 Integral | 9
 DIAGNOSIS
 SYSTEM STATUS
POWER-OFF POWER-OFF indicates whether voltage is
present at the power supply utility input. If
voltage is present, the power supply utility
has not disabled any component of the
appliance.
OVEN / FIREPLACE
AIR HEAT EXCH. DEFR.
EVAPORATOR DEFROST
 FAULT LIST
The fault memory contains the ten most recent fault messages. The
display, however, can show only six fault messages at a time. Turn
the scroll wheel to access the other entries in the fault memory.
26�04�01�0300
MAIN MENU
DIAGNOSIS
FAULT LIST
01. FAULT NO. 20 11:00:00 H 10 SEPT 14
02. FAULT NO. 06 11:01:00 H 10 SEPT 14
03. FAULT NO. 20 12:23:00 H 10 SEPT 14
04. FAULT NO. 06 12:24:00 H 10 SEPT 14
05. FAULT NO. 20 12:34:00 H 10 SEPT 14
06. FAULT NO. 06 12:35:00 H 10 SEPT 14
 PROGRAMS
If automatic mode is set, this is where you define the time pro-
grams that control the appliance.
 HEATING PROGRAM
HEATING CIRCUIT 1| HEATING CIRCUIT 2
You can set individual heating programs for heating circuits 1
and 2. This determines when and how often the appliance should
operate in day mode. At all other times, the appliance operates in
setback mode. You can select the set values for day and setback
mode under the menu item "ROOM TEMPERATURES".
First, select the days on which you want to enable the heating
function:
+
-
26�04�01�0301
MONDAY
MON
MAIN MENU
PROGRAMS
HEATING PROGRAM HC
HEATING CIRCUIT 1
- on individual days ("MONDAY", ... , "SUNDAY")
- from Monday to Friday ("MON - FRI")
- on Saturday and Sunday ("SAT - SUN")
- throughout the whole week ("MON - SUN")
Monday is initially offered.
 Select the day or a group of days.
 Confirm your selection with "OK".
You can now set three switching time pairs. The three switching
time pairs are shown on the display, to the right of the clock. A
switching time pair comprises the start time and end point, at
which the appliance returns to its previous state.
07:00 - 20:00
- -:- - - - -:- -
- -:- - - - -:- -
26�04�01�0299
MONDAY
MAIN MENU
PROGRAMS
HEATING PROGRAM HC
HEATING CIRCUIT 1
In this example, only one switching time pair has so far been
programmed. For switching time pairs 2 and 3, short dashes are
displayed instead of times. These switching time pairs are still
empty. Select one of the free switching time pairs with "OK" to
reach the area where you can set the associated start and end
time. Pressing "OK" brings up the display shown below. Set the
required time.
END
- -:- - - -:- -
TIME TIME
START
26�04�01�0302
MAIN MENU
PROGRAMS
HEATING PROGRAM HC
SETTINGS
Times can be entered in intervals of 15 minutes. You can set 16:30
or 16:45 h, but not 16:37 h. Confirm your entry with "OK".
Periods around midnight
Assume, for example, you want heating mode to be enabled from
22:00 h for four hours every Wednesday evening. This means the
period does not expire until the next day, Thursday, at 02:00h.
However, since the day ends at 00:00 h, two switching time pairs
are necessary for the required program. First, program the period
22:00 to 00:00h for Wednesday, then 00:00 to 02:00h for Thursday.
Deleting a switching times pair
Select the pair of switching times you want to delete. Go to the
start time change. Turn the scroll wheel to reduce the time. If you
reach 00:00 and continue to make a rotation, the pair of switch-
ing times is removed. The previously shown display appears, i.e.
dashes instead of numbers. Confirm again with OK.

OPERATION
Operation
10 | LWZ 304-404 Trend/LWZ 304 Integral www.stiebel-eltron.com
 DHW PROGRAM
Here, you can set the periods when DHW is heated with reference
to the set day temperatures. In the other phases, the set night
temperatures are followed. The times are set as for the heating
programs. You can select the set values for day and night mode
as described in the DHW chapter.
Example: You want to heat up DHW daily at two different times,
i.e. from 22:00h until 05:00h the following day, and then again
from 08:00h until 11:00h. Since the day begins at 00:00h, begin
programming at 00:00h. The first pair of switching times runs
from 00:00h until 05:00h. The second pair of switching times
starts at 08:00h and ends at 11:00h. The third switching time
pair runs from 22:00h until 24:00h.
The pairs of switching times should be selected so that the DHW
cylinder can be completely heated up between the start and stop
times (at least 3 hours).
 FAN PROGRAM
The setting is made as for the central heating and DHW programs.
 HOLIDAY PROGRAM
During the holidays, if nobody is in the house, central heating,
DHW and ventilation are not required in their full scope. All set
temperatures are set to match the set values of the standby func-
tion. Define the first and last days of the holiday. The setting is
made as described under "Time / date". At the end of the holiday,
the appliance runs according to the set programs again.
HOLS BEGINNING
DAY
MONTH
YEAR
HOUR
MINUTE
HOLIDAYS ENDING
DAY
MONTH
YEAR
HOUR
MINUTE
 PARTY PROGRAM
Under this parameter you can extend day mode for several hours.
Enter the start and end time of your party. Times can be set that
go beyond the end of the day the party starts.
 SETTINGS
 HEATING
Two heating circuits can be operated with this appliance, e.g. one
direct heating circuit for radiator heating system and one heating
circuit with mixer for underfloor heating system.
Enter the "ROOM TEMPERATURES HC1" submenu for settings ap-
plicable to the first heating circuit.
ROOM TEMPERATURES HC1
ROOM TEMPERATURE DAY HC1
ROOM TEMP. NIGHT HC1
ROOM TEMP. STANDBY HC1
MANUAL SET HC1
ROOM TEMPERATURE HC1
Select the required set room temperature for day, setback and
standby modes.
Example: Move the selection field to "ROOM TEMP. STANDBY" and
press OK. You reach parameter settings. The currently set value
is displayed. If you set the value to 10, the appliance ensures a
room temperature of 10°C when it is running in "STANDBY" mode.
"MANUAL SET HC": Under this parameter, set the heating flow
temperature for manual mode.
ROOM TEMPERATURE: This parameter, the display of the current
value, is only shown if a room temperature sensor is connected.
ROOM TEMPERATURES HC2
See chapter "ROOM TEMPERATURES HC1". Set the values in this
submenu accordingly.
HEATING CURVE HC1
GRADIENT HC1 P13
LOW END HC1 P14
ROOM INFLUENCE HC1 P15
FLOW PROPORTION HC1 P19
MAX. SET VALUE HC1
MIN. SET VALUE HC1
HEATING CURVE HC1
The room temperature will only remain constant irrespective of
the outside temperature if the correct heating curve has been
selected for the relevant type of building. Selecting the correct
heating curve is therefore vitally important. The more precisely
the heating curve is set, the more economically the appliance
works. Try therefore to optimise your heating curve. Reduce the
current heating curve until the flow temperature is just sufficient
for heating. The target is as flat a heating curve as possible.
 Fully open thermostatic valves (remove head) in a lead room,
for example living room or bathroom.
 At different outside temperatures, adjust the heating curve so
the required temperature is set in the lead room (living room
or bathroom). Now the room temperature in these rooms is
controlled with the heating curve (see next diagram).
Standard values to begin with:
Parameter Underfloor heat-
ing system
Radiator heating
system
GRADIENT 0.4 0.8
LOW END 3 K 10 K
ROOM TEMPERA-
TURE DAY (P01)
20 °C 20 °C

OPERATION
Operation
ENGLISH
www.stiebel-eltron.com LWZ 304-404 Trend/LWZ 304 Integral | 11
1
3
2
4
5
∆Y
∆X
D0000051930
X Outside temperature [°C]
Y Heating circuit temperature sensor [°C]
1 Gradient influence
Gradient = ΔY/ΔX
= Heating circuit temperature change/Outside temperature
change
2 Low end offset influence
3 Heating curve
4 Set room temperature influence
5 Low end
GRADIENT
With the "GRADIENT" parameter, you can set the extent to which a
change in the outside temperature causes a rise in the flow tem-
perature. Typical problem: Increase the gradient if the room tem-
perature is too low at low outside temperatures (approx. -10°C).
LOW END
By changing the "LOW END" parameter, you cause a parallel offset
of the heating curve. Typical applications are explained in the
chapter "Troubleshooting".
ROOM INFLUENCE
If you want to influence the heating curve through the room tem-
perature, install an auxiliary programming unit "FESComfort" in
your home. As the underfloor heating system has a delayed effect
on the room temperature, this can be counteracted via additional
heating such as solar irradiation or a fireplace. You must enter a
value > 0 for the "ROOM INFLUENCE" parameter.
Set heating circuit temperature= set heating circuit temperature
from heating curve+ ((set room temperature- actual room tem-
perature)* room influence* gradient/ 10)
FLOW PROPORTION
Flow means the pipework that supplies hot water to the heating
system. The return carries the cooled water from the heating sys-
tem to the heating system. With the "FLOW PROPORTION" param-
eter you determine whether your heating system should function
as a flow or return temperature-controlled system.
Flow pro-
portion
Effect
0Heating system with return temperature control
100 Heating system with flow temperature control
50 Spread control (50% return and 50% flow control)
30 Spread control (70% return and 30% flow control)
80 Spread control (20% return and 80% flow control)
Generally, values below 50 (recommendation:30) should be se-
lected for heating circuit 1 in order to restrict the influence of the
flow temperature. Particularly in spring and autumn, the flow
temperature is subject to naturally strong fluctuations because of
the heat pump being switched on and off. If these strong fluctua-
tions make it necessary, the booster stages would also be started,
although the heat pump alone would be capable of covering the
current heat demand.
No flow proportion is scanned for heating circuit2. Always enter
100 here, as the mixer circuit does not have its own return sensor.
MIN. SET VALUE/ MAX. SET VALUE
With these parameters, you set the minimum and maximum set
temperatures for the heating circuit. These values limit the heat-
ing curve in the upper and lower regions. Even if the calculated
heating curve would go beyond these limits, it is limited to these
set values.
HEATING CURVE
Under this parameter, you can display the heating curves for both
heating circuits.
60
40
50
30
20
10
00
-25 -20 -15 -10 -05 00 05 10 15 20 25
26�04�01�0348
MAIN MENU
HEATINGHEATING CURVE HC1
HEATING CURVE
THK °C
TA
°C
Note that parameter "Flow proportion" has an influence on heating
curve "HC1". This means the heating curve is distinctly lower than
the flow temperature curve. (see examples 1 and 2).
The heating curve for "HC2" is a flow temperature curve.

OPERATION
Operation
12 | LWZ 304-404 Trend/LWZ 304 Integral www.stiebel-eltron.com
Example 1 (heating curve 55/40)
Heating curve 55/40 for a radiator heating system (set room tem-
perature 20°C, low end 5°C, gradient 0.65, flow proportion 30%,
design temperature -15°C)
0
10
20
30
40
50
60
-15 -10 -5 0 5 10 15 20
1
3
2
26�04�01�0379
X Outside temperature [°C]
Y Heating temperature [°C]
1 Flow
2 Heating curve
3 Return
Example 2 (heating curve 35/28)
Heating curve 35/28 for underfloor heating (set room temperature
20°C, low end 1°C, gradient 0.3, flow proportion 30%, design
temperature -15°C)
0
5
10
15
20
25
30
35
40
-15 -10 -5 0 5 10 15 20
1
3
2
26�04�01�0380
X Outside temperature [°C]
Y Heating temperature [°C]
1 Flow
2 Heating curve
3 Return
If you have set the heating curve successfully, set the thermostatic
valves to the required temperature.
Note
Never reduce the temperature in the entire building by
closing all thermostatic valves. Instead, use the night
programs or select the set room temperature with the
"HOTTER/ COLDER" parameter.
4.5.1 STANDARD SETTING
These parameters are reserved for qualified contractors and are
described in the installation instructions.
 DHW
DHW TEMPERATURES
DHW SET DAY P04
DHW SET NIGHT P05
DHW SET STANDBY P06
DHW SET MANUAL P11
DHW TEMPERATURE
Select the set DHW temperatures here. Enter the values for day,
setback, standby and manual modes. Subject to operating mode,
the temperature in the DHW cylinder is brought to the correspond-
ing set value. The current water temperature in the cylinder is
shown under "DHW TEMPERATURE".
STANDARD SETTING
These parameters are reserved for qualified contractors and are
described in the installation instructions.
 VENTILATION
Here, you can set the parameters for the centralised ventilation
of your home.
VENTILATION STAGES
DAY STAGE
NIGHT STAGE
STANDBY STAGE
PARTY STAGE
MANUAL STAGE
TIME
UNSCHED. VENT TIME STAGE 0
UNSCHED. VENT TIME STAGE 1
UNSCHED. VENT TIME STAGE 2
UNSCHED. VENT TIME STAGE 3
VENTILATION STAGES
The fans can run in three different stages.
Stage
Ventilation for
humidity pro-
tection
0 Necessary ventilation for ensuring that the building
structure is protected under normal conditions of use
with somewhat reduced moisture loads, e.g. during
temporary absence of users and no drying of washing
in the residential unit.
Reduced venti-
lation
1 Ventilation necessary to meet minimum hygiene
standards and ensure protection of the building struc-
ture (humidity) under normal conditions of use with
partially reduced humidity and pollutant loads, e.g. as
a result of intermittent user absence.
Standard ven-
tilation
2 Ventilation necessary to meet hygiene standards and
ensure protection of the building structure when
users are present (standard mode).
Intensive ven-
tilation
3 Ventilation necessary from time to time, with a higher
air flow rate to reduce load peaks. For intensive ven-
tilation, it can be assumed that the user will assist (by
manually opening windows for a time).
TIME
Normally, the appliance controls when and for how long to venti-
late. However, via the quick access option "VENTILATION STAGES"
you can run ventilation outside the normal schedule.

OPERATION
Operation
ENGLISH
www.stiebel-eltron.com LWZ 304-404 Trend/LWZ 304 Integral | 13
Under "UNSCHED. VENT TIMESTAGE 1" determine for how many
minutes the fan should run, if you set the appliance to stage1 via
parameter "VENTILATION STAGES". You can set values between
0 and 1000 minutes in five-minute steps. Specify the ventilation
times for stages 0, 2 and 3 accordingly.
The selected ventilation stage will not be enabled for 20 seconds.
Quick ventilation with external pushbutton
With an external pushbutton that can be installed on site, you
can set ventilation immediately to stage3. Ventilation runs with
stage 3 and will only switch off after the time set in parameter
"UNSCHED. VENT TIMESTAGE 3".
Humidity protection ventilation (stage 0)
The control unit includes a humidity protection ventilation func-
tion. This is provided to protect against humidity damage, if ven-
tilation is not required. This could be, for example, during pro-
longed absence due to holidays. For this, in the "VENTILATION/
PARAMETER" menu, the humidity protection parameter must be
set to "ON". The humidity protection ventilation is activated after
a pause of 24 hours. Ventilation is inactive prior to the expiry of
the 24 hour period.
Ventilation starts if the relative humidity inside the room exceeds
a limit whilst ventilation is switched off (stage 0). Ventilation is
switched off again if the limit is undershot by more than the select-
ed hysteresis. The limit is dependent on the outside temperature.
 Please consult your qualified contractor.
Fan output correction (stage1/2/3) subject to humidity
For output stages 1, 2 and 3, the qualified contractor can activate a
correction subject to humidity. This is made subject to the relative
humidity in the room.
At low levels of relative humidity, such as in winter, for example,
the air flow rate will be reduced subject to the output reduction
parameter. This counteracts excessive drying out. In summer, the
humidity-dependent fan output correction can reduce excessive
humidity levels in rooms.
 Please consult your qualified contractor.
SERVICE
"RUNTIME FILTER:": This parameter indicates when the last filter
reset was carried out.
"RESET FILTER": This parameter enables you to carry out a filter
reset by selecting "On".
 DRY HEATING PROGRAM
The dry heating program is not necessary for daily requirements.
The explanation can be found in the installation instructions for
qualified contractors.
 COMMISSIONING
PROGRAMMING UNIT
CONTROL UNIT SOFTWARE
The programming unit's software version is displayed here.
CONTRAST
With the "CONTRAST" parameter, you can set the contrast between
the characters shown on the display and the display background.
BRIGHTNESS
LANGUAGE
Here you can select the language in which the display texts are
shown.
ROOM TEMP CORRECTION
If the room temperature captured by the programming unit does
not correspond with the actual room temperature, for example
if the sensor is mounted on a cold external wall, you can make a
correction at the appliance.
In the parameter "ROOM TEMP CORRECTION", enter the difference
between the actual room temperature and the room temperature
displayed on the programming unit.
Example:
Actual temperature 19 °C
Displayed temperature 21 °C
New parameter value -2
REL HUMIDITY CORRECTION
If the relative humidity in the room as measured on the program-
ming unit does not correspond to the real relative humidity in
the room, you can make a correction on the appliance. Should
the value displayed by the programming unit be too low, you can
increase the set value under the "REL HUMIDITY CORRECTION"
parameter.
CONTROLLER
SOFTWARE VERSION
"Software version" shows which software version is installed on
the control PCB. The software version indicates the appliance type.
SOFTWARE ID
"SOFTWARE ID" shows the consecutive number of the software.

OPERATION
Operation
14 | LWZ 304-404 Trend/LWZ 304 Integral www.stiebel-eltron.com
 TIME / DATE
TIME / DATE
In the "TIME / DATE" menu, enter the current time and date, so
the appliance can start the time programs you enter at the correct
time.
25. 13 08:23
DAY MONTH YEAR HOUR MINUTE
SEPT
D0000039141
MAIN MENU
TIME TIME / DATE
Position the selection indicator over the position "YEAR" and con-
firm with "OK". Set the current year and confirm with "OK". Set
the month accordingly. To help you set the "DAY", a calendar page
appears. Move the highlighter to the required day. The new value
is saved when you confirm with "OK".
SUMMERTIME MANUAL
Under the "SUMMERTIME MANUAL" menu item, you can set the
period for summertime.
SUMMERTIME AUTOMATIC
Instead of entering the time period for summer mode manually,
you can select the summertime specified at the factory. For this,
set the "SUMMERTIME AUTOMATIC" menu item to "ON".
 CONTRACTOR
As a user, only the fault list in the "FAULT SEARCH" submenu is of
importance for you.
The parameters in the "CONTRACTOR" menu have a great influence
on the appliance control properties, and are therefore protected
with a password to prevent incorrect settings. As an appliance
user, you can see these parameters, but if you jump to the next
menu level, you meet the code check.
FAULT SEARCH
If the appliance registers a fault, this is clearly displayed with the
message shown below.
!FAULT
CODE NO. 001
PLS INFORM CUST SERVICE
WEDNESDAY 10 SEPT 14 16:27 H
26�04�01�0303
If more than one fault occurs, the most recent fault is always
shown. Please inform your qualified contractor.
To see the usual default display, first enable the programming
unit by pressing "MENU" for 5seconds. The fault message is then
extended with a note requesting that you acknowledge the fault
by pressing OK for five seconds.
!FAULT
CODE NO. 001
PLS INFORM CUST SERVICE
TO ACCEPT PLS PRESS OK
FOR 5 SECONDS.
WEDNESDAY 10 SEPT 14 16:27 H
26�04�01�0303
For qualified contractors, chapter "Fault messages" in the instal-
lation instructions provides an overview of possible faults.
FAULT LIST
The fault list is also accessible to you as a customer. There, you
receive an overview of the faults most recently registered by the
appliance. The fault list contains the ten most recent fault mes-
sages. The display, however, can show only six fault messages at
a time. Scroll with the scroll wheel to access the other entries in
the fault list.
26�04�01�0300
MAIN MENU
CONTRACTOR
FAULT SEARCH
FAULT LIST
01. FAULT NO. 20 11:00:00 H 10 SEPT 14
02. FAULT NO. 06 11:01:00 H 10 SEPT 14
03. FAULT NO. 20 12:23:00 H 10 SEPT 14
04. FAULT NO. 06 12:24:00 H 10 SEPT 14
05. FAULT NO. 20 12:34:00 H 10 SEPT 14
06. FAULT NO. 06 12:35:00 H 10 SEPT 14
PROCESS VALUES
The displayed values are used for analysis in the event of a fault.
PROCESS STATUS
The displayed values are used for analysis in the event of a fault.
ANALYSIS
In the "ANALYSIS" submenu actual values are displayed that may
be useful to the service department when troubleshooting.

OPERATION
Cleaning, care and maintenance
ENGLISH
www.stiebel-eltron.com LWZ 304-404 Trend/LWZ 304 Integral | 15
5. Cleaning, care and maintenance
Note
Keep the air intake and discharge apertures on the exte-
rior wall free from snow and leaves.
 Regularly activate the safety valve to prevent it from becom-
ing blocked, e.g. by limescale deposits.
5.1 Replacing supply air and extract air filters
 Hold down "MENU" button for three seconds.
 If you have already navigated through the menu tree, press-
ing MENU will return you to the default display. If necessary
you may have to press menu several times.
 Use the scroll wheel to navigate to the "VENTILATION STAG-
ES" entry.
 Press "OK".
 Press "OK" again to set the "UNSCHEDULED VENT." parameter.
 Set the "UNSCHEDULED VENT." parameter to 0.
 Confirm with OK.
 Set the "UNSCHED. VENT TIMESTAGE 0" parameter to a suita-
ble value, e.g. 30minutes.
D0000039737
 Open the function module door.
2.
3.
4.
1.
D0000039691
1
2
1 Extract air filter
2 Supply air filter
 Undo the r.h. knurled nut by turning it anti-clockwise.
 Undo the l.h. knurled nut by turning it anti-clockwise to ena-
ble the filter cover to be pivoted downwards.
 Pull out the filter cassette.
Note
Ensure that you do not interchange the extract air and
supply air filters when reinserting them into the appli-
ance. The supply air filter cassette features two grip holes
at the front.
 Replace the filter.
 Push the new filter cassette into the appliance.
 Rotate the filter cover back into its original position and then
tighten the r.h. knurled nut clockwise.
 Tighten the l.h. knurled nut.
 At the programming unit, activate the "RESET FILTER" param-
eter ("SETTINGS/ VENTILATION/ SERVICE").
!
WARNING Injury
All other work on the appliance must only be carried out
by qualified contractors.
Note
Have the cross-countercurrent heat exchanger, outdoor
air filter, evaporator and fans checked and (if required)
cleaned once a year by a qualified contractor.
Cleaning the extract and supply air valve filters
 If installed, clean the extract air valve filters through which
air is extracted from the rooms.
 If installed, clean the supply air valve filters through which
air is supplied to the rooms.
 Clean the filter box (if present) attached to the outdoor air
connector on the rear of the appliance.

OPERATION
Troubleshooting
16 | LWZ 304-404 Trend/LWZ 304 Integral www.stiebel-eltron.com
6. Troubleshooting
6.1 Filter symbols appear
The appliance is equipped with an automatic filter contamination
detector. The constant flow rate control of the fans results in an
increase in fan speed when the filters become contaminated. This
increase in speed is evaluated to display a filter change require-
ment.
When the filters are contaminated, the following symbols are
displayed.
Filter change, top:
The extract air filter is contaminated. Please change the
extract air filter.
Filter change, bottom:
The supply air filter is contaminated. Please change the
supply air filter.
Filter change, top and bottom:
Extract air and supply air filters are contaminated or their
filter change intervals have expired. Please change the
extract air and supply air filters.
The filter symbol appears automatically after three months.
6.2 No hot water
Should you fail to obtain hot water, you can take the following
steps to remedy the situation yourself:
- If the appliance has no power: Check the fuse/circuit breaker
in your fuse box. If it has blown/tripped, replace/reset the
fuse/MCB. Notify your qualified contractor if the fuse/MCB
blows/trips again.
- If the appliance has power: Check whether the air intake/
discharge is blocked. Check whether a fault code is being
displayed, and if necessary, notify your qualified contractor.
Check whether the control unit is set correctly.
6.3 The safety valve of the cold water supply line
is dripping
This is perfectly normal during the heat-up process.
6.4 The fault symbol appears
Note If this symbol appears, it means a fault has occurred.
Notify your qualified contractor or call customer service.
6.5 The appliance leaks water
If water escapes from the appliance, shut it down immediately and
notify your qualified contractor.
6.6 Condensate on the outside of the appliance or
on the air hoses
In the drying out phase or when relative humidity is high (>60%),
it is normal for condensate to appear on the surface of the appli-
ance and on the thermally insulated air hoses. This should stop
when the house has dried out thoroughly which, subject to the
design, can take up to 2 years. If the room is used to dry washing
however, condensate can still form.
 Check whether the air hoses are fitted correctly, and that no
cold air escapes.
6.7 Noise is emitted
Since the appliance moves very large volumes of air, it cannot work
silently. However, there should not be any disturbing noises in the
living rooms and bedrooms. To achieve this, ensure that
- the appliance has been installed correctly.
- the installation room has a door that closes tightly.
- adequately sized silencers are integrated directly on the ap-
pliance in the supply air and extract air ducts.
- additional silencers are installed between bedrooms, nurser-
ies and living rooms.
- the air volumes have been adjusted and checked according to
the system design.
If you notice dragging noises when the fan or heat pump are in
operation, take the appliance out of use immediately and notify
your qualified contractor.
If dragging noises occur during heat pump operation, the exhaust
air fan may be the cause. During shipping, the fan may slightly
move in relation to the air nozzle. This may result in dragging
noises. If necessary, the exhaust air fan should be aligned as part
of the commissioning work.
6.8 The required flow temperatures are not
reached, particularly during drying out
When drying screed, output levels will be required that are far
above those necessary for standard heating operation. It can
therefore take a relatively long time before, for example, the low
end temperature is reached. However, the correct temperature
curve for drying out is ensured because the next stage in every
case is not started until the default temperature for the current
step has been reached. In case of all other faults, please always
notify your qualified contractor.
6.9 The accommodation is always too cold
Increase the low end temperature of the heating curve. Raise the
temperature by the number of degrees you require to obtain a
comfortable temperature.
6.10 The accommodation is always too hot
Reduce the low end temperature of the heating curve by the
number of degrees the room temperature exceeds a comfortable
temperature.

OPERATION
Troubleshooting
ENGLISH
www.stiebel-eltron.com LWZ 304-404 Trend/LWZ 304 Integral | 17
6.11 The accommodation is too cold in winter
If the temperature of your home in spring and autumn is OK,
but the rooms do not become warm enough when the outside
temperature drops sharply (-10°C), increase the gradient of the
heating curve. This means it will become slightly warmer in spring
and autumn. You should therefore slightly lower the low end tem-
perature.
Another reason might be the dual mode point. Increasing the
dual mode point, however, can lead to high energy consumption.
6.12 The accommodation is too hot in winter
If your heating system produces too much heat when temperatures
drop sharply, reduce the gradient of the heating curve. This means
your home will become slightly colder in spring and autumn. You
should therefore slightly raise the low end temperature.
6.13 The accommodation is too cold in spring and
autumn
One possible cause may be that summer mode is enabled and that
central heating is off, as a result. Switch the appliance to manual
mode or ask your qualified contractor to change the standard set-
tings. If the room temperature in spring and autumn (10°C) is too
low, reduce the gradient and increase the low end temperature.
6.14 The accommodation is too hot in spring and
autumn
 Increase the heating curve gradient slightly and reduce its
low end slightly.
6.15 The accommodation is too hot in summer
Stop summer mode and activate passive cooling, if required.
6.16 Air quality is too poor
 Select a higher fan stage.
6.17 The air in winter is too dry
 Select fan stage 1.
 Activate the humidity correction.
When going away, switch the appliance to reduced ventilation.
You can set a fan program for this. Here you set the time during
which the appliance runs in day mode. For the rest of the time,
the appliance runs at the fan stage that you set in the "NIGHT
STAGE" parameter.
6.18 Contact a qualified contractor
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).
000000-0000-000000
D0000039735

OPERATION
Menu structure
18 | LWZ 304-404 Trend/LWZ 304 Integral www.stiebel-eltron.com
7. Menu structure
Note
Some menu items are protected by a code and can only
be accessed and adjusted by a qualified contractor.
Menu item/parameter Options Direct Unit Description
 ACTUAL VALUES
 ROOM TEMPERATURE
ROOM TEMPERATURE HC1 °C This value is only displayed if the programming unit is being used as an
external programming unit. This value is not displayed if the programming
unit is built into the appliance.
SET ROOM TEMPERATURE HC1 34 °C
RELATIVE HUMIDITY HC1 % See "ROOM TEMPERATURE HC1".
ROOM TEMPERATURE HC2 °C See "ROOM TEMPERATURE HC1". The room temperature of the second
heating circuit will only be displayed if a room temperature sensor or an
external programming unit is connected.
SET ROOM TEMPERATURE HC2 °C
RELATIVE HUMIDITY HC2 % See "ROOM TEMPERATURE HC1".
 HEATING
OUTSIDE TEMPERATURE 32 °C
ACTUAL VALUE HC1 °C Heating circuit temperature, calculated from the flow and return tempera-
tures, weighted with the value set under "FLOW PROPORTION". Whilst DHW
is being heated, this parameter indicates the temperature with which the
DHW cylinder is being heated.
SET VALUE HC1 °C Default temperature for the heating circuit
ACTUAL VALUE HC2 °C
SET VALUE HC2 °C
FLOW TEMPERATURE °C The flow is the heating pipework between heat pump and heat consumer
(radiator or indirect coil inside the DHW cylinder). Here you can see the
temperature of the water in this pipe section.
RETURN TEMPERATURE °C The return is the heating pipework between heat consumer and the heat
pump. Here you can see the temperature of the water in this pipe section.
PRESSURE HTG CIRC bar
FLOW RATE l/min
 DHW
DHW TEMPERATURE °C Shows the current cylinder water temperature
DHW SET TEMPERATURE °C
 VENTILATION
VENTILATION AIR ACTUAL Hz Indicates the current supply air fan speed.
VENTILATION AIR SET m³/h This value indicates the percentage of maximum control voltage with which
the supply air fan operates. Supply air is the heated outdoor air that is
blown into the ventilation area (living room, bedroom, nursery).
EXTRACT AIR ACTUAL Hz Current speed of the extract air fan
EXTRACT AIR SET m³/h This value indicates the percentage of maximum control voltage with which
the extract air fan operates. Extract air is the stale air that is extracted from
the extract air area (bathroom, kitchen, WC).
EXTRACT AIR HUMIDITY %
 HEAT GENERATOR
HEATING STAGE
 HEAT PUMP
HOT GAS TEMPERATURE °C This value specifies the temperature of the gaseous refrigerant at the con-
denser inlet.
HIGH PRESSURE bar
LOW PRESSURE bar
EVAPORATOR TEMP. °C In the evaporator, the refrigerant is evaporated at low pressure. As this
happens, heat is extracted from the air flow.
CONDENSER TEMP. °C In the condenser, the refrigerant is liquefied at high pressure. This releases
heat which is transferred to the heating medium. In the condenser, the
refrigerant is liquefied at high pressure. This releases heat which is trans-
ferred to the heating medium.
EXPELLED AIR ACTUAL Hz Current speed of the exhaust air fan
EXPELLED AIR SET Set flow rate of the heat pump fan
COMPRESSOR STARTS
 AMOUNT OF HEAT
HEAT METER HTG DAY kWh Amount of heat that was transferred by the heat pump to the heating circuit
on this day.

OPERATION
Menu structure
ENGLISH
www.stiebel-eltron.com LWZ 304-404 Trend/LWZ 304 Integral | 19
Menu item/parameter Options Direct Unit Description
HEAT METER HTG TTL MWh Amount of heat that has been transferred by the heat pump to the heating
circuit since the appliance was commissioned.
HEAT METER DHW DAY kWh Amount of heat that was transferred by the heat pump to the DHW cylinder
on this day.
HEAT METER DHW TTL MWh Amount of heat that has been transferred by the heat pump to the DHW
cylinder since the appliance was commissioned.
HEAT M BOOST HTG TTL MWh Amount of heat that has been transferred by the electric emergency/boost-
er heater to the heating circuit since the appliance was commissioned
HEAT M BOOST DHW TTL MWh Amount of heat that has been transferred by the electric emergency/boost-
er heater to the DHW cylinder since the appliance was commissioned
HEAT M RECOVERY DAY kWh Amount of heat that was recovered from the ventilation system on this day.
HEAT M RECOVERY TTL MWh Amount of heat that has been recovered from the ventilation system since
the appliance was commissioned.
 RUNTIMES Here, the runtime of some appliance components since appliance commis-
sioning is shown.
COMPRESSOR HEATING h
COMPRESSOR DHW h
ELEC BOOSTER HEATING h
ELEC BOOSTER DHW h
 POWER CONSUMPTION
PWR CON HTG DAY kWh Power drawn by the compressor on this day for supplying the heating cir-
cuit.
PWR CON HTG TTL MWh Power drawn by the compressor since commissioning for supplying the
heating circuit
PWR CON DHW DAY kWh Power drawn by the compressor on this day for supplying the DHW cylinder
PWR CON DHW TTL MWh Power drawn by the compressor since commissioning for supplying the
DHW cylinder
 DIAGNOSIS
 SYSTEM STATUS
POWER-OFF
OVEN / FIREPLACE
AIR HEAT EXCH. DEFR.
EVAPORATOR DEFROST
 FAULT LIST

OPERATION
Menu structure
20 | LWZ 304-404 Trend/LWZ 304 Integral www.stiebel-eltron.com
Menu item/parameter Options Direct Unit Dis-
play
only
Min. Max. Standard value
304Trend/ Inte-
gral [404Trend]
Energy saving
recommenda-
tion
System
value
 PROGRAMS
 HEATING PROGRAM         
HEATING CIRCUIT 1
MONDAY Time period1| Time pe-
riod2| Time period3
TUESDAY Time period1| Time pe-
riod2| Time period3
WEDNESDAY Time period1| Time pe-
riod2| Time period3
THURSDAY Time period1| Time pe-
riod2| Time period3
FRIDAY Time period1| Time pe-
riod2| Time period3
SATURDAY Time period1| Time pe-
riod2| Time period3
SUNDAY Time period1| Time pe-
riod2| Time period3
MON - FRI Time period1| Time pe-
riod2| Time period3
SAT - SUN Time period1| Time pe-
riod2| Time period3
MON - SUN Time period1| Time pe-
riod2| Time period3
HEATING CIRCUIT 2 See HEATING CIRCUIT 1
 DHW PROGRAM See HEATING CIRCUIT 1
 FAN PROGRAM See HEATING CIRCUIT 1
 HOLIDAY PROGRAM
HOLS BEGINNING
DAY 1 31 1
MONTH 1 12 1
YEAR 0 99 11
HOUR 0 23
MINUTE 0 59
HOLIDAYS ENDING
DAY 1 31 1
MONTH 1 12 1
YEAR 0 99 11
HOUR 0 23 0
MINUTE 0 59
 PARTY PROGRAM
START 00:00 23:45
END 00:00 23:45
 STANDARD SETTING
MAX. ADVANCE 59 min 0 300 0
 SETTINGS
 HEATING
ROOM TEMPERATURES HC1
ROOM TEMPERATURE DAY HC1 01 °C 10 30 21 20
ROOM TEMP. NIGHT HC1 02 °C 10 30 21 20
ROOM TEMP. STANDBY HC1 03 °C 10 30 10
MANUAL SET HC1 10 °C 10 65 35
ROOM TEMPERATURE HC1 °C X
ROOM TEMPERATURES HC2
ROOM TEMPERATURE DAY HC2 °C 10 30 21 20
ROOM TEMP. NIGHT HC2 °C 10 30 21 20
ROOM TEMP. STANDBY HC2 °C 10 30 10
MANUAL SET HC2 °C 10 65 35
ROOM TEMPERATURE HC2 °C X
HEATING CURVE HC1
GRADIENT HC1 13 0 5 0.4 0.2 for underfloor
heating system
LOW END HC1 14 °C 0 20 3 5
ROOM INFLUENCE HC1 15 0 100 0
FLOW PROPORTION HC1 19 0 100 30
MAX. SET VALUE HC1 °C 10 65 50