STIEBEL ELTRON WWS 20 Instruction Manual

BEDIENUNG UND INSTALLATION
OPERATION AND INSTALLATION
UTILISATION ET INSTALLATION
Warmwasser-Wärmepumpe in Splitbauweise | DHW heat pump in a split design |
Chauffe-eau thermodynamique de conception split
» WWS 20
1:1

www.stiebel-eltron.com WWS 20| 37
ENGLISH
CONTENTS | SPECIAL INFORMATION CONTENTS
SPECIAL INFORMATION
OPERATION
1. General information ��������������������������������������� 38
1.1 Safety instructions����������������������������������������������38
1.2 Other symbols in this documentation ����������������������38
1.3 Information on the appliance �������������������������������� 39
1.4 Units of measurement ����������������������������������������� 39
1.5 Standardised output data ������������������������������������� 39
2. Safety�������������������������������������������������������� 39
2.1 Intended use����������������������������������������������������� 39
2.2 Incorrect use����������������������������������������������������� 39
2.3 General safety instructions ����������������������������������� 39
2.4 Test symbols �����������������������������������������������������40
3. Appliance description ������������������������������������� 40
3.1 Heating the DHW cylinder ������������������������������������ 40
3.2 Appliance operation outside the application limits������ 41
3.3 Frost protection (air as heat source)������������������������ 41
3.4 Display and control elements �������������������������������� 41
4. Menu structure��������������������������������������������� 42
4.1 Switching on heat pump �������������������������������������� 43
4.2 Standard display ������������������������������������������������ 43
4.3 DHW heating����������������������������������������������������� 43
4.4 Fan mode���������������������������������������������������������44
4.5 Heat pump mode selection ����������������������������������� 45
4.6 Operation with external signal transmitter ��������������� 45
4.7 Electric heater rod���������������������������������������������� 46
4.8 Setting the time������������������������������������������������� 46
4.9 Parameter level �������������������������������������������������46
5. Cleaning, care and maintenance ������������������������� 47
6. Troubleshooting �������������������������������������������� 47
INSTALLATION
7. Safety�������������������������������������������������������� 49
7.1 General safety instructions ����������������������������������� 49
7.2 Instructions, standards and regulations ������������������� 49
8. Appliance description ������������������������������������� 49
8.1 Standard delivery����������������������������������������������� 49
8.2 Accessories������������������������������������������������������� 49
8.3 Incorrect use����������������������������������������������������� 49
9. Preparations������������������������������������������������ 49
9.1 Transport ��������������������������������������������������������� 49
9.2 Storage������������������������������������������������������������ 50
9.3 Installation site��������������������������������������������������50
9.4 Heat source (air draw-off point)����������������������������� 51
10. Installation�������������������������������������������������� 51
10.1 Wall mounting bracket installation ������������������������� 51
10.2 Siting the appliance �������������������������������������������� 52
10.3 Water connection ����������������������������������������������� 52
10.4 Condensate drain ����������������������������������������������� 54
10.5 Power supply ����������������������������������������������������54
10.6 Temperature sensor�������������������������������������������� 55
11. Commissioning ��������������������������������������������� 55
11.1 Initial start-up��������������������������������������������������� 55
11.2 Recommissioning����������������������������������������������� 56
12. Appliance shutdown ��������������������������������������� 56
13. Maintenance and cleaning �������������������������������� 56
13.1 Removing the casing������������������������������������������� 56
13.2 Removing casing components separately ����������������� 57
13.3 Cleaning the evaporator��������������������������������������� 57
13.4 Water treatment������������������������������������������������� 57
13.5 Descaling the appliance ��������������������������������������� 57
14. Specification ������������������������������������������������ 58
14.1 Dimensions and connections��������������������������������� 58
14.2 Hydraulic connection diagram ������������������������������� 59
14.3 Wiring diagrams ������������������������������������������������ 61
14.4 Heating output �������������������������������������������������� 65
14.5 Power consumption �������������������������������������������� 65
GUARANTEE
ENVIRONMENT AND RECYCLING
14.6 Data table ��������������������������������������������������������66
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.
- Observe all applicable national and regional reg-
ulations and instructions during installation.
- The appliance is not approved for outdoor
installation.
- Observe the minimum clearances (see chap-
ter "Installation/ Preparations/ Siting the
appliance").
- Observe the requirements concerning the instal-
lation room (see chapter "Installation/ Prepara-
tions/ Installation site").

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SPECIAL INFORMATION | OPERATION
General information
- In the case of a permanent connection, the ap-
pliance must be able to be separated from the
power supply by an isolator that disconnects all
poles with at least 3mm contact separation. Con-
tactors, mains isolators or fuses can be used for
this.
- Observe the safety measures to prevent contact
with dangerous 'live' currents.
- Observe the MCB/fuse protection required for
the appliance (see chapter "Specification/ Data
table").
- 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.
- The appliance is pressurised. During the heat-up
process, expansion water will drip from the safety
valve.
- Install a type-tested safety valve in the cold water
supply line.
- The maximum pressure in the cold water supply
line must be at least 20% below the response
pressure of the safety valve. If the maximum
pressure in the cold water supply line is higher,
install a pressure reducing valve.
- Size the drain so that water can drain off unim-
peded when the safety valve is fully opened.
- Fit the discharge pipe of the safety valve with
a constant downward slope and in a room free
from the risk of frost.
- The safety valve discharge aperture must remain
open to atmosphere.
OPERATION
1. General information
The chapters "Special information" and "Operation" are intended
for both users 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 a new user if required.
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 passages carefully.
Symbol Meaning
Material losses
(appliance damage, consequential losses and environmen-
tal pollution)
Appliance disposal
!
!

OPERATION
Safety
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ENGLISH
 This symbol indicates that you have to do something. The ac-
tion you need to take is described step by step.
1.3 Information on the appliance
Symbol Meaning
Never cover the appliance
1.4 Units of measurement
Note
All measurements are given in mm unless stated oth-
erwise.
1.5 Standardised output data
Explanations to determine and interpret the specified standardised
output data
Standard: EN 16147
The output data specifically mentioned in text, diagrams and
technical datasheets has been calculated according to the test
conditions of the standard shown in the heading of this section.
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 this
method deviates from the conditions defined in the norm shown in
the heading of this section, any deviations can have a considerable
impact. Additional factors that have an influence on the test values
are the measuring equipment, the system configuration, 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 intended for DHW heating within the application
limits detailed in chapter "Specification/ Data table".
The appliance is intended for domestic use. It can be used safely
by untrained persons. The appliance can also be used in non-do-
mestic environments, e.g. in small businesses, 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.
2.2 Incorrect use
The following are not permitted:
- Heating liquids other than DHW
- Operating the appliance with an empty DHW cylinder
- Operating the appliance outside the application limits (see
chapter "Specification")
- Interrupting the power supply
2.3 General safety instructions
Only qualified contractors should carry out the electrical work and
installation of this appliance. Qualified contractors are responsible
for adherence to all applicable regulations.
The appliance should only be operated once it is fully installed
and all safety equipment has been fitted.
!
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.
WARNING Electrocution
Contact with live components presents a threat to life.
Damage to the insulation or to individual components
may result in a threat to life.
 If there is damage to the insulation, switch off the
power supply and arrange a repair.
All work on the electrical installation must be carried
out by a qualified contractor.
WARNING Burns
The water in the DHW cylinder can be heated to temper-
atures in excess of 60°C. There is a risk of scalding at
outlet temperatures above 43°C.
 Ensure you do not come into contact with the water
when discharged.
WARNING Burns
Touching hot components can lead to burns.
When working on hot components, always wear protec-
tive working clothing and safety gloves.
The pipework connected to the DHW outlet of the appli-
ance can reach temperatures in excess of 60°C.
WARNING Burns
The appliance is filled with refrigerant at the factory.
In the event of refrigerant escaping due to a leak, avoid
coming into contact with the refrigerant or inhaling the
released vapours. Ventilate the rooms affected.
!
CAUTION Injury
Never place any objects on top of the appliance. If objects
are left on the appliance, noise emissions may increase
due to resulting vibrations, and the objects could fall
and cause injury.
!
Material losses
If you disconnect the appliance from the power supply,
the operating status of the primary pump can no longer
be guaranteed.
 Never interrupt the power supply to the appliance.

OPERATION
Appliance description
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!
Material losses
Never cover the appliance. Covering the air intake or air
discharge leads to a reduced air supply. If the air supply
is restricted, the operational reliability of the appliance
cannot be guaranteed.
!
Material losses
Only operate the appliance when the DHW cylinder has
been filled.
!
Material losses
Keep the appliance installation site and the air draw-off
point free from air contaminated with oil or salt and from
explosive or corrosive substances (e.g. chlorine, sulphur,
ammonia).
2.4 Test symbols
See type plate. The type plate is located on the side of the ap-
pliance.
3. Appliance description
The appliance is a fully wired DHW heat pump in a hydraulic split
design. When combined with an externally connected DHW cyl-
inder, the appliance supplies DHW heating from several draw-off
points using renewable energy. Subject to the power supply and
user draw-off behaviour, the DHW cylinder is heated automatically
to the selected set temperature.
The appliance extracts heat from the ambient air at the air draw-
off point. This heat is used to heat up the water in the DHW cylinder
with added electric power. The amount of electrical energy and
time required to heat-up the DHW depend on the temperature of
the air drawn in.
Note
As the heat is drawn off from the supply air, the appliance
operates with a defined cooling capacity on the exhaust
air stream. In recirculation air mode, this can then cause
a temporary cooling of the installation room.
 When selecting the type and size of installation
room, ensure that energy use is compensated over a
period of 24hours and the lower application limit of
the appliance is not undershot. Please also observe
the following factors:
- Expected appliance runtime per day
- The resulting cooling energy
- Existing heat sources in the installation room
(e.g.freezer, tumble dryer, central heating)
- Heat flux from adjoining rooms
Note
When the intake air temperature drops, the appliance
output is reduced and the heat-up time is extended.
The appliance is designed for indoor installation. It can be installed
as a recirculation air appliance and thus use the existing waste
heat from other heat sources in the installation room (e.g. wash-
ing machine, freezer). Alternatively the appliance allows you to
connect an air duct to route the supply air from another room or
to remove the exhaust air from the installation room. For times
when there is no DHW demand (compressor inactive), the fan
speed can be set separately.
Note
In heat pump mode (compressor active), the fan always
operates at a fixed rated speed set at the factory (see
chapter "Specification/ Data table"), irrespective of the
fan speed set for operating without a compressor.
The appliance also extracts moisture from the ambient air, which
turns into condensate. The condensate is removed from the ap-
pliance via the condensate drain.
The appliance features an electronic control unit with LCD for set-
ting functions and operating modes.
Depending on which hydraulic cylinder connection is selected, an
immersion heater can be connected to the appliance control unit
and controlled from there.
External signal transmitters can be integrated via the built-in
switching input, for example a photovoltaic system to increase
the percentage of on-site power or an off-peak tariff signal.
Heat pump operating principle
A closed circuit within the appliance contains refrigerant (see
chapter "Specification/ Data table"). This refrigerant evaporates
at low temperatures.
In the evaporator, which extracts heat from the air drawn in, the
refrigerant changes from a liquid into a gaseous state. A com-
pressor draws in the gaseous refrigerant and compresses it. This
increase in pressure raises the refrigerant temperature.
That requires electrical energy. The energy (motor heat) is not lost,
but reaches the downstream condenser together with the com-
pressed refrigerant (plate heat exchanger). There, the refrigerant
indirectly transfers heat to the passing DHW. An expansion valve
then reduces the still prevalent pressure and the cycle starts again.
The appliance is fitted with a DHW primary pump at the factory.
!
Material losses
The internal primary pump should be started periodically
(every 20hours for 3seconds) to prevent it seizing up.
 Never interrupt the power supply to the appliance.
 To switch off the appliance (standby mode), keep the
power button pressed for approx. 2seconds.
3.1 Heating the DHW cylinder
A temperature sensor captures the amount of heat in the DHW
cylinder. The water in the DHW cylinder is heated up if the amount
of heat is lower than that required to achieve the set temperature.

OPERATION
Appliance description
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ENGLISH
3.2 Appliance operation outside the application
limits
3.2.1 Ambient temperatures below the application limit
At temperatures below the lower application limit, hoar frost may
form on the evaporator depending on the air humidity and water
temperature.
Temperature sensor F3 captures and monitors the evaporator
temperature. If the evaporator temperature falls below 0°C for
longer than 120minutes, the evaporator will defrost. This defrost-
ing raises the evaporator temperature again.
Defrosting is registered as successful if the evaporator tempera-
ture rises to >6°C within 20minutes. If defrosting is unsuccessful,
two more attempts will be made. If these attempts are still unsuc-
cessful, the heat pump will be switched off and the error message
Er47 will appear on the display.
 To guarantee fault-free operation of the appliance, make sure
you operate the appliance within its application limits (see
chapter "Specification/ Data table").
Note
Heat-up times are longer while the evaporator is defrost-
ing.
3.2.2 Ambient temperatures above the application limit
The safety equipment switches the appliance off if the upper ap-
plication limit is exceeded. Following a cooling time of several
minutes the appliance is switched back on automatically. The ap-
pliance is switched off again if the intake air temperature rises
back above the permissible temperature value.
 To guarantee fault-free operation of the appliance, make sure
you operate the appliance within its application limits (see
chapter "Specification/ Data table").
3.3 Frost protection (air as heat source)
If the intake air temperature is too low, the error message Er57
will appear on the display.
If an immersion heater is installed in the DHW cylinder, it can
continue DHW heating while the fault remains. This requires heat
pump mode to be disabled.
3.4 Display and control elements
The appliance is equipped with an integral digital controller. You
can use the controller display and control elements to call up and
set the appliance data.
3.4.1 Display
The display consists of a display and programming unit.
D0000045887
1
2
1 Display unit
2 Programming unit
Keys
Button Designation Description
Power button Put the appliance into standby mode or restart
it
Menu key Calling up the controller menu
Back button Return to the previous menu
Down button Scroll through the menu, adjust values,
display the set DHW value
Up button Scroll through the menu, adjust values,
display the optional temperature sensor in the
DHW cylinder (only when display sensor F2 is
connected)
OK button Save settings,
select submenus,
acknowledge error messages
Symbols
Symbol Meaning bright dimmed flashes
DHW heating DHW heating
active
DHW heating ac-
cording to time
program
Pasteurisation
function active
Fan mode Fan mode active Fan mode
switched off
-
Compressor Compressor
active
Compressor
switched off
Maintenance
(every 2500
hours run)
Setting the
temperature
Setting the tem-
perature
- -
Setting the
time
Setting the time - Time needs re-
setting
Electric heater
rod
Immersion
heater active
Immersion heat-
er switched off
-
MENU
OK

OPERATION
Menu structure
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4. Menu structure
Standard display (chapter 4.2)
MENU
DHW heating (chapter 4.3)
OK
DHW mode selection (chapter 4.3.1)
OK
Auto* = Automatic mode
FASt = Quick heat-up ▲▼
▲
Set DHW value (chapter 4.3.2)
OK
0...60
(52*) ▲▼
▲
Set pasteurisation value (chapter 4.3.3)
OK
0...60*
▲▼
▲
DHW start time (chapter 4.3.1)
OK
00:00*...23:59
▲▼
▲
DHW stop time (chapter 4.3.1)
OK
00:00...23:59*
▲▼
▲
Pasteurisation function start time (chapter 4.3.3)
OK
00:00*...23:59
▲▼
▲
Pasteurisation function time interval (chapter 4.3.3)
OK
0*...14
(0 = Pasteurisation func-
tion disabled)
▲▼
▲Fan mode (chapter 4.4) OK
Fan mode selection (chapter 4.4)
OK
oFF* = Fan switched off
on = Continuous mode
Auto = Automatic mode
▲▼
▲
Fan speed (chapter 4.4)
OK
1...9*
▲▼
▲
Fan start time (chapter 4.4)
OK
00:00*...23:59
▲▼
▲
Fan stop time (chapter 4.4)
OK
00:00...23:59*
▲▼
▲
Heat pump mode selection
(chapter 4.5) OK →
oFF = Compressor
switched off
Auto* = Automatic mode
dEFr = Manual defrosting
▲▼
▲
Immersion heater mode se-
lection (chapter 4.7) OK →
oFF* = Immersion heater
switched off
Auto = Automatic mode
▲▼
▲
Time (chapter 4.8)
OK →
00:00...23:59
▲▼
▲Parameter level (chapter 4.9) OK
Parameter setting (chapter 4.9.1)
▲Call up operating data (chapter 4.9.2)
▲Enter password
* Factory setting
11 /34

OPERATION
Menu structure
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ENGLISH
MENU Menu key
OK OK button
▲Up button
▼Down button
 Press the Back button to go from one menu level to the high-
er menu level.
4.1 Switching on heat pump
 Keep the power button pressed for 2seconds.
The standard display appears.
4.2 Standard display
When you are not navigating through the menu structure, the
standard display will be shown. The standard display shows the
actual temperature inside the DHW cylinder (control sensor F1)
and the current operating state of the appliance.
D0000045843
12
1 Operating state
2 Temperature inside the DHW cylinder
Note
While you are in the standard display, the Up and Down
buttons function like short-cut buttons to call up the cur-
rent set DHW value and, if display sensorF2 is connected,
the current actual temperature in the DHW cylinder.
4.3 DHW heating
The water in the DHW cylinder is heated up if:
- There is a current demand for domestic hot water
- DHW heating is not blocked by the time program
There is a current demand for domestic hot water when the water
temperature in the DHW cylinder is 5K lower than the selected
set DHW value.
4.3.1 DHW mode selection
The appliance features two different operating modes for DHW
heating:
- Automatic mode
- Quick heat-up
In automatic mode, DHW heating is controlled via an individually
adjustable time program. The DHW is heated using all the heat
sources which are enabled for automatic mode (see chapter "Pa-
rameter level/ Parameter setting").
In quick heat-up mode, the water is heated immediately to the
selected set DHW value, irrespective of automatic mode. Once the
selected set DHW value has been reached, the appliance switches
back to automatic mode.
Note
Automatic mode is the default factory setting.
DHW heating mode setting
You are in the standard display.
 Press the Menu button.
The DHW heating submenu appears.
D0000045844
 Press the OK button.
The DHW mode selection submenu appears.
D0000045845
 Press the OK button.
The operating mode flashes.
 Set the required operating mode using the Up/Down buttons.
 Confirm your entry with the OK button.
 Keep pressing the Back button to return to the standard
display.
Automatic mode time program setting
Symbol Parameter Description
on DHW start time:
The time when DHW heating is enabled (factory
setting = 00:00)
off DHW stop time:
The time when DHW heating is blocked (factory
setting = 23:59)
Example: DHW heating is blocked between 06:00-18:00
D0000045896
1
2
1 DHW heating enabled
2 DHW heating blocked
Quick heat-up activation and setting
Symbol Parameter Description
FASt Once-only quick heat-up starts as soon as "FASt" is
set.
PSEt
└SEt
b03 Select the heat source for quick heat-up
0 = Heat pump only (factory setting)
1 = Heat pump and immersion heater

OPERATION
Menu structure
44| WWS 20 www.stiebel-eltron.com
4.3.2 DHW value setting
You are in the standard display.
 Press the Menu button.
The DHW heating submenu appears.
 Press the Up button.
The set DHW value submenu appears.
D0000045846
1 2
1 Set DHW value display (set value1)
2 Current set DHW value
 Press the OK button to confirm your selection.
The set DHW value flashes.
 Set the required DHW value using the Up/Down buttons.
 Confirm your entry with the OK button.
 Keep pressing the Back button to return to the standard
display.
4.3.3 Pasteurisation function
The pasteurisation function is used to meet hygiene require-
ments. It is implemented using the heat pump and other active
heat sources. The DHW cylinder is heated periodically to the set
pasteurisation value (set value2).
Symbol Parameter Description
2 60 Set pasteurisation value: Set temperature in the
DHW cylinder for the pasteurisation function (fac-
tory setting = 60°C)
hour Pasteurisation function start time
(factory setting = 00:00)
dAY Pasteurisation function time interval: The time
interval during which the pasteurisation function
is periodically implemented
(factory setting = 0)
PSEt
└SEt
b02 Maximum pasteurisation function heat-up time: If
the set pasteurisation value is not achieved within
the time set here, the heat-up process is termi-
nated (see chapter "Parameter level/ Parameter
setting").
(factory setting = 4.0h)
Note
The pasteurisation function may be influenced by the
DHW heating time program.
 Set the pasteurisation function start time in the peri-
od where DHW heating is enabled.
Note
If the power supply has been interrupted, e.g. following a
power failure, the selected heat-up time can be extended
up to 6hours.
4.4 Fan mode
The fan can be switched on irrespective of the heat pump mode.
For this fan mode, you can set the fan speed and a time program.
Alternatively, the fan can be switched on and off via an external
switching input.
Fan mode setting
Symbol Parameter Description
Auto Fan mode selection
oFF = Fan switched off (factory setting)
on = Fan operating at rated speed, compressor
active
Auto = Automatic mode (fan operating via separate
time program)
SEt Fan speed (automatic mode)
Stage* 012345678 9
% 0 45 60 71 81 89 94 98 99 100
(factory setting = 9)
on Fan start time (automatic mode)
(factory setting = 00:00)
oFF Fan stop time (automatic mode)
(factory setting = 23:59)
PSEt
└SEt
A04 Function of switching input E3
0 = No function (factory setting)
3 = External fan control:
K3 open = Fan switched off, no DHW demand
K3 closed = Fan operates at set speed
* The fan stage data is based on a freely blowing appliance
with no external air routing lines.
Example switching diagram:
D0000045897
1 3
2
1 Compressor active (light grey)
2 Fan operating at rated speed
3 Compressor switched off (dark grey)
4 Fan in automatic mode, independently of compressor
5 Fan stage curve
4.4.1 External fan control
Alternatively, the fan can be switched on and off from an external
control unit via switching input E3 (see chapter "Junction box").
To do this, fan mode selection must be set to "Auto". The time
program for fan mode takes priority over the external fan control,
so switching inputE3 is active only while fan mode is enabled.

OPERATION
Menu structure
www.stiebel-eltron.com WWS 20| 45
ENGLISH
Example switching diagram:
D0000045898
1
1 Fan speed curve
4.5 Heat pump mode selection
Symbol Parameter Description
Auto Heat pump mode selection
oFF = Compressor switched off
Auto = Automatic mode (according to the period
DHW heating is enabled)
defr = Manual defrosting of the compressor
(factory setting = Auto)
Note
When the heat pump compressor is switched off, the fan
operates in automatic mode. The heat pump does not
provide any DHW heating.
Note
The heat pump is set to automatic mode at the factory.
4.6 Operation with external signal transmitter
You can switch off the heat pump or set it to a higher set value
using floating switching inputsE2 and E3 (see chapter "Junction
box").
You can configure E2 and E3 via the "Parameter setting" submenu
as follows:
Symbol Parameter Description
PSEt
└SEt
A03 Function of switching input E2
0 = No function (factory setting)
1 = Power supply utility shutdown:
K2 open = Heat pump (and immersion heater)
switched off
K2 closed = Heat pump is running
A04 Function of switching input E3
0 = No function (factory setting)
1 = Power supply utility shutdown:
K2 open = Heat pump (and immersion heater)
switched off
K2 closed = Heat pump is running
2 = Smart Grid function:
K3 open = DHW set value is delivered
K3 closed = Pasteurisation set value is delivered
Note
The compressor has a minimum idle time of 20minutes.
Note
An external shutdown takes priority over increasing the
set value.
4.6.1 Power supply utility shutdown
Note
Shutting down the heat pump power supply utility has
no effect on ventilation.
The heat pump shuts down automatically when:
- Switching input E2 is open
- The set value for DHW temperature has been reached
The display shows the word St OP.
Example switching diagram:
D0000045900
1
T1 Temperature in the DHW cylinder (sensor F1)
1 Minimum compressor idle time (20min)
4.6.2 Set value increase
If you have your own photovoltaic system, you can increase the
delivered set value via switching input E3 when you have a low
electricity tariff. This will then deliver the pasteurisation set value
(2) instead of the DHW set value (1).
Example switching diagram:
D0000045901

OPERATION
Menu structure
46| WWS 20 www.stiebel-eltron.com
Note
The relay in the inverter must meet the following re-
quirements:
- Potential-free relay (240VAC / 24VDC, 1A) with
N/O contact
- Adherence to safety regulations and standards for
safety extra low voltage
- The switching output must be programmed so that
the relay closes or opens if certain limits are exceed-
ed or undershot (inverter output level).
If necessary, check with the inverter manufacturer wheth-
er the product meets the stated criteria.
4.7 Electric heater rod
When there is an increased demand for hot water or quick heat-up,
you can also install an immersion heater in your DHW cylinder,
depending on your hydraulic connection.
Note
However, you cannot install an immersion heater if you
heat your DHW cylinder via an inlet pipe (see chapter
"Connection to the DHW cylinder").
The immersion heater controls the temperature in the DHW cyl-
inder to the DHW set value, independently of the heat pump or
any other heat sources.
During the pasteurisation function, the immersion heater controls
the pasteurisation set value.
Immersion heater configuration
Note
The immersion heater is not registered by the control
unit and not visible in the menu structure until you set
"Parameter A01 = 3".
Symbol Parameter Description
PSEt
└SEt
A01 Registering the immersion heater
0 = Not installed (factory setting)
3 = Immersion heater installed in the DHW cylinder
Auto Immersion heater mode selection
oFF = Immersion heater switched off (factory setting)
Auto = Automatic mode (according to the period
DHW heating is enabled)
PSEt
└SEt
E01 Immersion heater start temperature
(factory setting = 0.0°C)
E02 Immersion heater stop temperature
(temperature differential to DHW set value)
(factory setting = 0.0K)
b03 Select the heat source for quick heat-up
0 = Heat pump only (factory setting)
1 = Heat pump and immersion heater
Note
At outputs up to 2kW, the immersion heater can be con-
nected directly to the junction box. An external contactor
is required for outputs above 2kW.
 The immersion heater should only be installed in the
DHW cylinder by a qualified contractor.
4.8 Setting the time
To select the current time, proceed as follows:
 Press the Menu button.
The DHW heating menu appears.
 Press the Up button until you reach the time setting menu.
The current time is displayed.
 Press the OK button.
The hour display flashes.
 Set the current hour using the Up/Down buttons.
 Press the OK button.
The minute display flashes.
 Set the current minute using the Up/Down buttons.
 Confirm your selection with the OK button.
Note
 You will need to set the time again following a long
power interruption.
4.9 Parameter level
4.9.1 Setting parameters
Parameter Description
A01 Configuring the immersion heater
0 = Not installed (factory setting)
3 = Immersion heater installed in the DHW cylinder
A02 Configuring contact F1
1 = Control sensor in DHW cylinder (factory setting)
0 = Switching input for external heat demand
A03 Function of switching input E2
0 = No function (factory setting)
1 = Power supply utility shutdown:
K2 open = Heat pump (and immersion heater) switched off
K2 closed = Heat pump is running
A04 Function of switching input E3
0 = No function (factory setting)
1 = Power supply utility shutdown:
K2 open = Heat pump (and immersion heater) switched off
K2 closed = Heat pump is running
2 = Smart Grid function:
K3 open = DHW set value is delivered
K3 closed = Pasteurisation set value is delivered
3 = External fan control:
K3 open = Fan switched off, no DHW demand
K3 closed = Fan operates at set speed
b01 DHW set value following defrost error (error code Er47)
Immersion heater takes over DHW heating
5...60 (factory setting = 38°C)
b02 Maximum pasteurisation function heat-up time
1...8 (factory setting = 4.0 hours)
b03 Select the heat source for quick heat-up
0 = Heat pump only (factory setting)
1 = Heat pump and immersion heater
E01 Immersion heater start temperature
0...60 (factory setting = 0.0°C)
E02 Immersion heater stop temperature
(temperature differential to DHW set value)
0...30 (factory setting = 0.0K)

OPERATION
Cleaning, care and maintenance
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ENGLISH
4.9.2 Calling up operating data
To call up the operating data for your heat pump, proceed as
follows:
 Navigate to the "Call up operating data" menu level (see
chapter "Menu structure").
 Press the OK button.
You are given the option to call up the program version.
 To call up the program version, press the OK button. To
navigate instead to the operating data, press the Up/Down
buttons.
 You can call up the following operating data:
Parameter Description
Pro Program version
d01 Actual value sensor F1
d02 Actual value sensor F2
d03 Actual value sensor F3
d04 Actual value sensor F4
d11 Compressor hours run (0 - 9999)
d12 Compressor hours run (10.000+)
d13 Immersion heater hours run (0 - 9999)
d14 Immersion heater hours run (10.000+)
5. Cleaning, care and maintenance
WARNING Electrocution
-Only clean the exterior of the appliance.
-Never open the appliance.
-Do not insert objects through the grille into the in-
terior of the appliance.
-Never spray the appliance with water.
-Never spray water into the appliance.
!
WARNING Injury
Maintenance work, such as checking electrical safety,
must only be carried out by a qualified contractor.
- Use a damp cloth to clean the casing sections. Never use
abrasive or corrosive cleaning agents.
- Clean the air intake and discharge apertures every six
months. Cobwebs or other kinds of contamination can re-
strict the air supply to the appliance.
- Have the safety assembly and the evaporator checked regu-
larly by a qualified contractor.
- Check that the condensate drain is clear and remove any dirt.
6. Troubleshooting
Problem Cause Remedy
DHW temperature
too low
Water consumption
too high
Reduce consumption or switch on
immersion heater
DHW value set too low DHW value checking
Actual value F1 in-
correct
Checking sensor F1
Intake air temperature
too low (heating out-
put too low)
Switching on immersion heater
Circulation pump in
continuous mode
Check time switch, test temper-
ature controller and non-return
valve
Non-return valve
blocked
Clear non-return valve by tapping
gently
Heating slider open Closing heating slider
Defrosting active Wait 20minutes
Compressor
running, fan not
running
Start capacitor faulty Customer support notification
Winding damage Customer support notification
Compressor and
fan running with-
out heating the do-
mestic hot water
No air flow, evaporator
contaminated
Cleaning evaporator with water
Evaporator iced up Defrosting evaporator
Air lines blocked Cleaning air lines
Refrigerant shortage Customer support notification
Expansion valve does
not open
Customer support notification
Compressor not
running, fan run-
ning
Flow direction faulty Customer support notification
Compressor faulty Customer support notification
Constant water
discharge
Safety valve does not
close
Vent or replace
Cylinder faulty Closing supply line
Cylinder dripping Check seals, retighten if neces-
sary
Water discharges
only when appli-
ance is operating
Condensate
Condensate drain
blocked
Cleaning the condensate drain
Smell No siphon installed in
condensate drain
Siphon installation
Water in the siphon Filling with water
Noise Gurgling noise Water level in siphon too low, fill
with water
Splashing noise Condensate drain blocked, clean
Nothing on the
display
Power supply inter-
rupted
Checking power supply
Immersion heater
switched on, but
not heating
Superheating Safety thermostat acknowledge-
ment
Electrical connection
faulty
Qualified contractor to replace
the electrical connection

OPERATION
Troubleshooting
48| WWS 20 www.stiebel-eltron.com
Problem Cause Remedy
Er36 High pressure
shutdown
Actual value F1 in-
correct
Qualified contractor to check
sensor F1
DHW cylinder not full DHW cylinder filling
Refrigerant circuit Customer support notification
Sludge or scale block-
ing condenser
Clean condenser, replace if nec-
essary
Flow rate too low Check external pressure drops
and compare with a reliable
pressure drop (see chapter "Spec-
ification")
Air in the system Check whether the system has
been vented (see chapter "Com-
missioning/ Filling the DHW
cylinder")
Circulation pump is
jammed
Unjamming circulation pump
Er47 Defrost error Intake air temperature
too low
Set heat pump to "OFF" and heat
domestic hot water temporarily
with immersion heater
Er57 Frost protec-
tion heat source
Intake air temperature
too low
Set heat pump to "oFF" and heat
domestic hot water temporarily
with immersion heater,
Install ventilation flaps
HP symbol flashes Time interval for
testing the protective
anodes has expired
(approx. 1.5-2years)
Test protective anodes and re-
place if necessary, qualified con-
tractor to reset the timer
Messages on the display
CODE Meaning Remedy
E1H Sensor F1 faulty, lead break Sensor checking
E1L Sensor F1 faulty, short circuit Sensor checking
E2H Sensor F2 faulty, lead break Sensor checking
E2L Sensor F2 faulty, short circuit Sensor checking
E3H Sensor F3 faulty, lead break Sensor checking
E3L Sensor F3 faulty, short circuit Sensor checking
E4H Sensor F4 faulty, lead break Sensor checking
E4L Sensor F4 faulty, short circuit Sensor checking
EP Error in parameter memory Appliance disconnection from power
supply then reconnection
Er36 High pressure shutdown Acknowledge error with OK
Er47 Defrost error Acknowledge error with OK
Er57 Frost protection heat source Error is acknowledged automatically
FroS Frost protection DHW cylinder Start immersion heater, if installed
Error is acknowledged automatically
once the fault has been remedied
StOP Power supply utility active See chapter “Operation with external
Cr id Set value increase active signal transmitter”
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).
Sensor values
All the control unit temperature sensors have the same charac-
teristics: PTC, type KTY81-121.
Temperature [°C] Resistance [Ohm] Maximum deviation [+/-°C]
-10 739.9 2.1
-9 739.9 2.1
-8 753.0 2.0
-7 759.5 2.0
-6 766.2 2.0
-5 772.8 2.0
-4 779.5 2.0
Temperature [°C] Resistance [Ohm] Maximum deviation [+/-°C]
-3 786.3 1.9
-2 793.1 1.9
-1 799.9 1.9
0806.7 1.9
1 813.6 1.8
2820.5 1.8
3827.5 1.8
4834.5 1.8
5841.5 1.8
6848.6 1.7
7855.7 1.7
8862.8 1.7
9870.0 1.7
10 877.2 1.6
11 884.5 1.6
12 891.8 1.6
13 899.1 1.6
14 906.5 1.5
15 913.9 1.5
16 921.3 1.5
17 928.8 1.5
18 936.3 1.5
19 943.9 1.4
20 951.5 1.4
21 959.1 1.4
22 966.8 1.4
23 974.5 1.3
24 982.2 1.3
25 990.0 1.3
26 997.8 1.3
27 1005.7 1.4
28 1013.6 1.4
29 1021.5 1.4
30 1029.4 1.4
31 1037.4 1.5
32 1045.5 1.5
33 1053.5 1.5
34 1061.7 1.6
35 1069.8 1.6
36 1078.0 1.6
37 1086.2 1.6
38 1094.5 1.7
39 1102.8 1.7
40 1111.1 1.7
41 1119.5 1.8
42 1127.9 1.8
43 1136.3 1.8
44 1144.8 1.9
45 1153.3 1.9
46 1161.9 1.9
47 1170.5 1.9
48 1179.1 2.0
49 1187.8 2.0
50 1196.5 2.0

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ENGLISH
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.
Take note of the appliance type plate and chapter "Specification".
8. Appliance description
The appliance is a DHW heat pump in a hydraulic split design. It
can be connected in various ways with an external DHW cylinder
(see chapters "Water connection/ Connection to the DHW cylinder"
and "Specification/ Hydraulic connection diagram").
Note
The appliance is suitable for DHW cylinders up to 500l
capacity.
 The application for 500l DHW cylinders must be
checked in advance by the system installer.
The heat pump has been designed to provide enough domestic hot
water for a household of 5 people. The maximum volume of DHW
cylinders that can be connected is therefore limited by the thermal
output of the appliance and the expected maximum heat-up times.
 When installing the appliance, check whether any installed
DHW cylinders are large enough to meet the short-term DHW
demand.
The thermal output of the heat pump depends on heat source
temperature (supply air) and set DHW value.
 To calculate the appliance output at different intake tem-
peratures and the corresponding heat-up times, please use
the output diagram in the chapter "Specification/ Heating
output").
 Observe the minimum volume of the installation room and
the heat-up time during normal domestic use when com-
bined with a 300l cylinder (see chapter "Specification/ Data
table").
 In recirculation air mode, when selecting the type and size
of installation room, ensure that energy use is compensated
over a period of 24hours and the lower application limit of
the appliance is not undershot.
Please also observe the following factors: Expected runtime
per day, the resulting cooling energy, existing heat sources
in the installation room (e.g. freezer, tumble dryer, central
heating), heat flux from adjoining rooms.
8.1 Standard delivery
The following are delivered with the appliance:
- 1 wall mounting bracket with 4 anti-vibration mounts
- 1 temperature sensor
- 1 sensor well for temperature sensor
- 1 set of operating and installation instructions
8.2 Accessories
8.2.1 Required accessories
- Compatible DHW cylinder (see chapter "Connection to the
DHW cylinder")
- Cold water safety assembly
8.2.2 Additional accessories
Note
Different accessories will be required depending on your
hydraulic connection.
- Inlet connector set, part number 072997
- Electric heater rod
- Ventilation accessories
8.3 Incorrect use
The following are not permitted:
- Operating the appliance when the casing is open
- Filling the appliance with a refrigerant other than the one
detailed in chapter "Specification/ Data table"
Observe the list of requirements regarding the installation room
and non-permissible installation sites (see chapter "Installation
site").

50| WWS 20 www.stiebel-eltron.com
INSTALLATION
Preparations
9. Preparations
9.1 Transport
!
CAUTION Injury
 Take note of the weight of the appliance.
 Use suitable transport aids (e.g. a sack truck) and
enough personnel for transportation.
!
Material losses
The appliance casing is not designed to withstand strong
forces. Incorrect handling can lead to material losses of
considerable extent.
 Observe the information on the packaging.
 Only remove the packaging shortly before the instal-
lation.
- Store and transport the appliance in its packaging.
- You may transport the appliance carefully over short distanc-
es at an angle of up to 45°.
- During storage and transport, the ambient temperature
should be between -20°C and +45°C.
Vehicular transport
!
Material losses
The appliance must be stored and transported according
to the instructions on the packaging.
9.2 Storage
If it is necessary to store the appliance for a prolonged period
before installation, observe the following information:
- Leave the appliance in its packaging during storage.
- Only store the appliance in a vertical position.
- Store the appliance in a location that is dry and largely
dust-free.
- Protect the appliance from coming into contact with corrosive
substances.
- Ensure the appliance is not subjected to shocks or vibrations.
9.3 Installation site
The appliance is not approved for outdoor installation.
Further requirements regarding the installation room and appli-
ance positioning, to prevent appliance damage:
- The installation site must be free from flammable, highly
combustible gases and substances, as well as high levels of
dust.
- The installation room must be dry and free from the risk of
frost.
- The intake temperature of the appliance must be within the
permissible application limits (see chapter "Specification/
Data table").
- The appliance must be installed on a even, horizontal sur-
face. If the appliance is not horizontally level, there may be a
risk of appliance damage.
- Ensure the appliance is not subjected to shocks or vibrations.
Use the anti-vibration mounts supplied.
- Observe the safety clearances and protection zones.
- Always leave sufficient space to provide access for instal-
lation, maintenance and cleaning. The required minimum
clearances must be maintained (see chapter "Minimum
clearances").
- Ensure the operation of other equipment in the installation
room is not impaired.
- Lighting equipment and pipes must not be installed above
the appliance.
- To keep the duct lengths to the draw-off points as short as
possible, we recommend installing the connected DHW cylin-
der close to the kitchen or bathroom.
- To prevent adverse effects from operating noise, never install
the appliance close to bedrooms.
- Observe the minimum volume of the installation room and
the heat-up time during normal domestic use (see chapter
"Specification/ Data table").
- In recirculation air mode, when selecting the type and size
of installation room, ensure that energy use is compensated
over a period of 24hours and the lower application limit of
the appliance is not undershot.
Please also observe the following factors: Expected runtime
per day, the resulting cooling energy, existing heat sources
in the installation room (e.g. freezer, tumble dryer, central
heating), heat flux from adjoining rooms.
The following installation sites and air draw-off points are not
permissible, as there may be a risk of appliance damage:
- Places where the air contains ammonia (e.g. sewage works,
animal sheds)
- Locations where the air is contaminated with oil or grease
- Generally places with a loaded or aggressive atmosphere
(e.g. cement or flour dust, hairspray (e.g. hairdressing salon)
- Saline environments (e.g. in areas <2-5km from the coast,
depending on main wind direction)
- Locations where the air contains chlorine or chloride (e.g.
swimming pools, salt works)
- Environments with thermal water
- Areas in proximity to high frequency machines (inverters for
large motors, radar)
 Also check in the wider environment around the planned
installation site for anything which may have adverse effects
on the installation site or the air supply.
Note
You can improve the efficiency of the appliance by utilis-
ing the waste heat from other appliances to heat the DHW
cylinder, e.g. boilers, tumble dryers or freezers.

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ENGLISH
INSTALLATION
Installation
9.3.1 Minimum clearances
≥360
≥670
≥670 ≥500
140
D0000045906
 Maintain the minimum clearances.
9.4 Heat source (air draw-off point)
- The air draw-off point must be free from flammable, highly
combustible gases and substances, as well as high levels of
dust.
- The intake air must not contain aggressive materials such as
chlorine, ammonia or sulphur.
- There should be a high average air temperature at the air
draw-off point.
- When selecting the air draw-off point, always factor in the
required air volume and air flow rate (see chapter "Specifica-
tion/ Data table").
- If using ventilation accessories, the connection ducts must
have a minimum diameter of 160mm.
- The total length of the supply air and extract air ducts must
not exceed 20m. A maximum of three right-angled bends
may be installed. For each additional bend installed, the total
duct length must be reduced by 2.5m.
- Always use profiles with lip seals when connecting an air
duct.
- Install the air ducts in straight lines. Avoid installing ducts
along sharp edges or around tight corners.
- Install the air ducts horizontally and sloping slightly to the
intake and discharge apertures. You may also install an
evaporation bag.
- Insulate the air duct and all connections in line with insula-
tion standards if used for waste heat or outside air to prevent
condensation on these components.
- If restricted space conditions mean that an air flow "short
circuit" could occur between the air discharge and air intake
in recirculation air mode, we recommend fitting a 45° bend
to the air discharge.
!
Material losses
If the air duct and its connections are not insulated,
condensate may form on the air duct depending on the
appliance operating mode. Condensate can damage the
appliance. Dripping condensate can damage furniture or
floor coverings.
 Insulate the air duct, including the air connector to
the appliance, so that it is vapour diffusion-proof.
!
Material losses
There is a risk of frost damage if the appliance draws
in outdoor air and the temperature of this air may fall
below 0°C.
Fit ventilation flaps with low resistance for outdoor instal-
lation. When the heat pump is idle, the ventilation flaps
prevent cold air flowing into the building. Otherwise the
appliance may enter a fault state (fault message Er57).
Note
The output data applies to recirculation air mode. If the
air is channelled through an air duct, the output and
efficiency data may fall.
10. Installation
!
WARNING Injury
Incorrect installation can lead to serious injury or ma-
terial losses.
Before any work, ensure sufficient clearances for the
installation.
Handle sharp-edged components carefully.
Note
The low weight of the appliance means that it can be
mounted on a wall.
 If mounting the appliance on a wall, only use the
supplied wall mounting bracket with anti-vibration
mounts.
10.1 Wall mounting bracket installation
!
Material losses
The appliance must be positioned horizontally to prevent
damage.
 When assembling the wall mounting bracket, ensure
that the rail supports are aligned horizontally.
 Ensure that the wall structure is able to bear the weight force
exerted by the heat pump plus wall mounting bracket.
 Select suitable screws and rawl plugs to secure the wall
mounting bracket on the wall.
 Mark out the positions of the holes to be drilled on the wall.
To do this, hold the rail supports against the wall at the re-
quired installation height.
 Ensure that no electrical cables are damaged through drilling
the holes.
 Drill the holes and insert rawl plugs.
 Secure the rail supports to the wall using the screws
provided.
 Ensure that the wall mounting bracket is flush with the wall.
 Check that the rail supports are horizontally and vertically
level, using a spirit level.
 Level the rail supports by undoing and tightening the screws.
 Tighten all screws.

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INSTALLATION
Installation
360
410 80
D0000046845
1
2
1 Anti-vibration mount
2 Support points for anti-vibration mounts
 Fit the anti-vibration mounts onto the appliance support
points provided on the wall mounting bracket rails.
!
Material losses
Have a qualified contractor check the installation to en-
sure that the appliance is permanently and securely in-
stalled.
10.2 Siting the appliance
!
Material losses
The appliance must be positioned horizontally to prevent
damage.
 Position the appliance on a horizontal and even sub-
strate.
 When fixing to a wall mounting bracket, ensure that
the rail supports are aligned horizontally.
!
Material losses
Take note of the appliance's weight and centre of gravity.
 Position the appliance in the final installation site.
 When fixing to a wall mounting bracket, the depressions on
the device underside must be positioned on the anti-vibra-
tion mounts on the bracket.
 Attach the fully wired junction box underneath the appliance
between the wall mounting brackets.
10.3 Water connection
!
Material losses
Carry out all water connection and installation work in
accordance with regulations.
!
Material losses
The water must be treated, as appropriate to the temper-
ature and hardness of the water. The appliance must be
descaled regularly as required.
 Observe the details specified in the chapter "Installa-
tion/ Descaling the appliance".
Note
Generally, heat pumps should always have flexible
connections. Aim to avoid the transmission of struc-
ture-borne sound when installing pipes.
Note
The length of the pipework between the appliance and
the DHW cylinder should be as short as possible. If the
pipework between the appliance and the DHW cylinder
is longer, the output and efficiency data may fall.
The following material combinations are approved for metal pipe-
work installations:
Cold water inlet DHW outlet
Copper pipe Copper pipe
Steel pipe Steel pipe or copper pipe
 Thoroughly flush the pipework before connecting the ap-
pliance. Foreign bodies, such as welding pearls, rust, sand
or sealant can impair the operational reliability of the
appliance.
Safety valve
The appliance has been designed to connect to a closed DHW
cylinder. Provide the appliance with a pressure relief valve.
 Install a type-tested safety valve in the cold water supply
line. The response pressure of the safety valve must be below
or equal to the permissible operating pressure of the DHW
cylinder.
The safety valve protects the appliance against unacceptable ex-
cess pressure. The diameter of the cold water supply line must be
no greater than the diameter of the safety valve.
- Ensure that the expansion water escaping from the safety
valve can drip into a drain, e.g. a tank or funnel.
- Ensure the drain cannot be shut off.
- Size the drain so that water can drain off unimpeded when
the safety valve is fully opened.
- Ensure that the discharge pipe of the safety valve is open to
atmosphere.
- Fit the discharge pipe of the safety valve with a constant
downward slope and in a room free from the risk of frost.
Pressure reducing valve
The maximum pressure in the cold water supply line must be at
least 20% below the response pressure of the safety valve. If the
maximum pressure in the cold water supply line is higher, install
a pressure reducing valve.
Drain valve
 Install a suitable drain valve at the lowest point in the cold
water inlet line.

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ENGLISH
INSTALLATION
Installation
Thermal insulation
 Insulate the DHW line against heat loss in accordance with
locally applicable regulations.
DHW circulation
The heat losses incurred in the DHW circulation line and the elec-
trical power consumption of the circulation pump reduce the effi-
ciency of the system. The cooled water in the DHW circulation line
mixes with the cylinder content. Avoid installing a DHW circulation
line. Where that is not possible, the DHW circulation pump must
be controlled thermally or by time switch.
Gravity brake
To prevent thermal DHW circulation, you should install a gravity
brake between the appliance and the DHW cylinder, depending
on your hydraulic connection (see chapter "Connection to the DHW
cylinder").
Water treatment and application limits
Depending on water temperature and hardness, the following
water treatments should be carried out according to DIN 1988-
200:2012-05:
dH [°] DHW temperature <60°C DHW temperature > 60°C
0-8.4
(soft)
No water treatment necessary Periodic descaling recommended
(see chapter "Descaling the ap-
pliance")
8.4-14
(medium)
No water treatment necessary Periodic descaling necessary (see
chapter “Descaling the appliance”)
14-21
(hard)
Periodic descaling necessary
(see chapter "Descaling the
appliance")
Softening
>21 Softening Use is not recommended
Reduce the DHW temperature
Where water quality fluctuates significantly and the DHW temper-
atures are high (>60°C), we recommend annual inspection by a
qualified contractor.
Water constituent Concentration
(mg/l or ppm)
Time limits
Investigation time
following sampling
Alkalinity (HCO3-) <70
70-300
>300
0
+
0
within 24h
Sulphate[1] (SO42-) <100
<200
>200
+
0
-
No limit
HCO3-/SO42- >1.0
<1.0
+
-
No limit
Electrical conductivity <10µS/cm
10-500µS/cm
>500µS/cm
0
+
0
No limit
pH[2]
<7.0
7.0-9.0
>9.0
0
+
0
within 24h
Ammonium (NH4+) <2
2-20
>20
+
0
-
within 24h
Chloride (Cl) <100
100-200
>200
+
0
-
No limit
Free chlorine (Cl2) <1
1-5
>5
+
0
-
within 5h
Hydrogen sulphide (H2S) <0.05
>0.05
+
-
No limit
Water constituent Concentration
(mg/l or ppm)
Time limits
Investigation time
following sampling
Free (aggressive)
carbon dioxide (CO2)
<5
5-20
>20
+
0
-
No limit
Total hardness (°dH) 4-14 No limit (see chapter
"Water treatment")
Nitrate[1] <100
>100
+
0
No limit
Iron[3] (Fe) <0.2
>0.2
+
0
No limit
Aluminium (Al) <0.2
>0.2
+
0
No limit
Manganese[3] (Mn) <0.1
>0.1
+
0
No limit
+ Resistance under normal conditions
0 Corrosion may occur, especially if other factors are rated as 0
- Use is not recommended
[1] Sulphates and nitrates act as inhibitors of pitting corrosion
caused by chloride in pH-neutral environments
[2] Generally, a low pH value (below6) increases the risk of
corrosion. A high pH value (above7.5) reduces the risk of
corrosion.
[3] Fe3+and Mn4+are strong oxidising agents and can increase
the risk of local corrosion in stainless steel.
SiO2above 150ppm increases the risk of scale build-up
!
Material losses
To prevent damage to the plate heat exchanger, ensure
that the water is free from contamination (e.g. sludge,
sediment).
 If necessary, install a filter in the cold water supply
line.
10.3.1 Connection to the DHW cylinder
You have various options for connecting the appliance to your
DHW cylinder.
Note
Observe the information and limitations in the chapter
"Specification/ Hydraulic connection diagram".
Note
To determine the maximum length of the connection line
between the appliance and DHW cylinder, it may be nec-
essary to subtract higher pressure drop values from the
residual head of the internal circulation pump, subject to
the type of hydraulic connections employed.

54| WWS 20 www.stiebel-eltron.com
INSTALLATION
Installation
Heating the DHW cylinder via the inlet pipe
- The DHW cylinder must have a G1 hot water connector with a
male thread at top centre.
- The inlet pipe must protrude down to the lower third of the
DHW cylinder.
- Installing the inlet pipe cannot be influenced by any integral
indirect coils or threaded immersion heaters.
- To prevent thermal DHW circulation, you should install a
gravity brake between the appliance and the DHW cylinder.
- Pressure drop from the pipework and inlet pipe must not
exceed the residual head of the appliance circulation pump
(pressure drop from inlet pipe = approx. 16hPa).
- The minimum distance from the DHW connector to the ceiling
of the installation room must be at least 65cm. Otherwise
the cylinder must be tipped in order to insert the inlet pipe.
Heating the DHW cylinder via inlet connectors on the sides
- The connection to the appliance must be on the side about
half way up the DHW cylinder.
- To prevent thermal DHW circulation, you should install a
gravity brake between the appliance and the DHW cylinder.
- Pressure drops from the pipework must not exceed the resid-
ual head of the appliance circulation pump.
Heating the DHW cylinder via the integral smooth tube indirect
coil
- To comply with heating system regulations, the appliance
and DHW cylinder must be connected with a diaphragm ex-
pansion vessel and a safety valve.
- The indirect coil must have a transfer area of min. 1.4m2.
- The thermal output of the appliance must be able to be
transferred via the indirect coil with a temperature differen-
tial (flow/return) of 5K.
- Pressure drops from the pipework and smooth tube indirect
coil must not exceed the residual head of the appliance circu-
lation pump.
- The integral circulation pump is set at the factory to stage2
with the corresponding available residual head and the ac-
companying rated output data (see chapter "Specification/
Data table").
The circulation pump is located under the appliance casing
and can be set to max. stage3 (residual head 1.5m).
For information on how to open the appliance casing, see the
chapter "Installation/ Maintenance and cleaning".
Note
At a temperature differential of 5K between the flow and
return, the thermal output of the heat pump (see chapter
"Specification") must be transferred via the indirect coil
in the DHW cylinder.
Due to the additional heat transfer, this installation may
result in different and lower output and efficiency data.
10.4 Condensate drain
Cooling the intake air in the evaporator separates the condensate.
Depending on the volume and humidity of the intake air, up to
0.3l/h of condensate may form.
 Route the condensate drain away from the heat pump along
the rear of the appliance.
 Make sure that the condensate can drain off freely.
 Use a suitable condensate pump if there is insufficient fall.
Take the building characteristics into account.
!
Material losses
Do not permanently connect the condensate drain to the
drainage system.
Ammonia vapours rising from the drains can damage the
heat exchanger fins as well as other components.
 Install a funnel with a stench trap on the condensate
drain.
10.5 Power supply
WARNING Electrocution
Carry out all electrical connection and installation work
in accordance with national and regional regulations.
WARNING Electrocution
If the appliance is permanently connected to the power
supply, ensure that the appliance can be separated from
the power supply by an isolator that disconnects all poles
with at least 3mm contact separation. Contactors, mains
isolators or fuses can be used for this.
WARNING Electrocution
 Observe the safety measures to prevent contact
with dangerous 'live' currents.
WARNING Electrocution
Coming into contact with 'live' components presents a
threat to life. Disconnect the appliance from the power
supply before carrying out work on the control panel.
Prevent the power supply from being switched on while
you are working on the system.
WARNING Electrocution
Insufficient earthing can lead to electrocution. Ensure
the appliance is earthed according to locally applicable
requirements.
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.
!
Material losses
The specified voltage must match the mains voltage. Ob-
serve the type plate.
!
Material losses
Never connect the appliance to the power supply before
the DHW cylinder is filled.
10.5.1 Power supply
The appliance is delivered with a power cable with a standard
plug.

www.stiebel-eltron.com WWS 20| 55
ENGLISH
INSTALLATION
Commissioning
10.5.2 Junction box
!
Material losses
Applying voltage to the switching inputs at the junction
box could destroy the contacts.
 Never apply any voltage to the switching inputs.
 Always use floating contacts.
A junction box is permanently wired to the back of the appliance
to enable you to connect optional inputs and outputs or an im-
mersion heater. You can find the connection diagram inside the
cover of the junction box.
9 PE F1 F2 E2 E3N
D0000045922
F1 Controller sensor
F2 Optional display sensor
E2 Power supply utility shutdown
E3 Power supply utility shutdown, set value increase or ex-
ternal fan control
!
Material losses
The booster heater is connected at pin 9, N and PE. The
max. permissible connected load is 2kW.
10.6 Temperature sensor
F1
F2
D0000045888
Contact Description
F1 DHW cylinder middle
Control sensor for heat pump and immersion heater,
Standard display sensor to show actual temperature inside the
DHW cylinder
F2
(optional)
Optional display sensor to show actual temperature inside the top
of the DHW cylinder
Activate by pressing the Up button while in standard display
10.6.1 Contact F1
Contact F1 as control sensor input
 Connect the DHW cylinder temperature sensor supplied at
the factory to contact F1.
Contact F1 as external switching input
!
Material losses
Applying voltage could destroy contact F1.
 Never apply any voltage to contact F1.
 Always use floating contacts.
Contact F1 can be configured as a switching input which allows
an external DHW demand.
Contact F1 then loses its measuring capability. This makes it im-
possible to control temperature via a heat pump control unit.
Depending on your settings, only the heat pump or all the enabled
heat sources will become active.
Example: Contact closed = DHW demand
D0000045889
Contact F1 configuration
Symbol Parameter Description
PSEt
└SEt
A02 Configuration of contact F1
1 = Control sensor in DHW cylinder
0 = Switching input for external heat demand
11. Commissioning
11.1 Initial start-up
!
Material losses
Never connect the appliance to the power supply before
the DHW cylinder is filled.
11.1.1 Filling the DHW cylinder
WWS%20SBB%20mit%20Lanze
1
4
3
2
1 DHW outlet
2 Cold water inlet
3 Hot water draw-off point
4 Shut-off valves