STIEBEL ELTRON WPL 15 AS Instruction Manual

OPERATION AND INSTALLATION
Air | water heat pump
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
SPECIAL INFORMATION
OPERATION
1. General information �����������������������������������������3
1.1 Relevant documents_____________________________________________ 3
1.2 Safety instructions_______________________________________________ 3
1.3 Other symbols in this documentation _______________________ 4
1.4 Units of measurement __________________________________________ 4
1.5 Standardised output data______________________________________ 4
2. Safety����������������������������������������������������������4
2.1 Intended use______________________________________________________ 4
2.2 Safety instructions_______________________________________________ 4
3. Appliance description ���������������������������������������5
3.1 Properties _________________________________________________________ 5
3.2 Function ___________________________________________________________ 5
4. Settings �������������������������������������������������������5
5. Maintenance and care ���������������������������������������6
6. Troubleshooting ����������������������������������������������6
INSTALLATION
7. Safety����������������������������������������������������������7
7.1 General safety instructions ____________________________________ 7
7.2 Instructions, standards and regulations ____________________ 7
8. Appliance description ���������������������������������������7
8.1 Accessories________________________________________________________ 7
9. Preparation ���������������������������������������������������7
9.1 Sound emissions_________________________________________________ 7
9.2 Minimum clearances____________________________________________ 8
9.3 Preparing the installation location___________________________ 8
9.4 Installing the supply lines______________________________________ 8
9.5 Siting _______________________________________________________________ 8
9.6 WPM heat pump manager ____________________________________ 11
9.7 Buffer cylinder __________________________________________________11
9.8 Preparing the electrical installation ________________________ 11
10. Installation�������������������������������������������������� 12
10.1 Transport _________________________________________________________ 12
10.2 Heating water connection_____________________________________ 12
10.3 Flow and return connection __________________________________ 12
10.4 Fitting the push-fit connectors_______________________________ 12
10.5 Oxygen diffusion________________________________________________ 13
10.6 Filling the heating system ____________________________________ 13
10.7 Minimum flow rate _____________________________________________ 14
10.8 Setting the flow rate on the heating side __________________ 14
10.9 Condensate drain _______________________________________________ 15
10.10 External second heat generator _____________________________ 16
10.11 High limit safety cut-out for underfloor heating
systems ___________________________________________________________ 16
11. Electrical connection��������������������������������������� 16
11.1 Access to the terminal area___________________________________ 16
11.2 WPL 15 AS| WPL15ACS_______________________________________ 18
11.3 WPL20A| WPL20AC| WPL25A| WPL25AC____________ 18
11.4 WPL25AS| WPL25ACS_______________________________________ 19
11.5 Closing the terminal area _____________________________________ 19
11.6 Ribbon heater ___________________________________________________ 19
12. Commissioning ��������������������������������������������� 20
12.1 Checks before commissioning________________________________ 20
12.2 Using the appliance with an external second heat
generator_________________________________________________________ 21
12.3 Initial start-up ___________________________________________________ 21
12.4 Appliance handover ____________________________________________ 22
13. Settings ����������������������������������������������������� 22
13.1 Silent mode ______________________________________________________ 22
14. Appliance shutdown ��������������������������������������� 22
14.1 Standby mode ___________________________________________________ 22
14.2 Power interruption _____________________________________________ 22
15. Maintenance ������������������������������������������������ 22
16. Troubleshooting �������������������������������������������� 23
16.1 Checking the IWS DIP switch settings ______________________ 23
16.2 Light emitting diodes (LEDs)__________________________________ 25
16.3 Reset button _____________________________________________________ 25
16.4 Resetting the high limit safety cut-out _____________________ 25
16.5 Fan noise _________________________________________________________ 25
17. Specification ������������������������������������������������ 27
17.1 Dimensions and connections_________________________________ 27
17.2 Wiring diagram _________________________________________________ 30
17.3 Application limit ________________________________________________ 34
17.4 Output diagrams ________________________________________________ 35
17.5 Data table ________________________________________________________ 41
GUARANTEE
ENVIRONMENT AND RECYCLING


General information
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
- 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 potential risks. Children must
never play with the appliance. Children must
never clean the appliance or perform user
maintenance unless they are supervised.
- The connection to the power supply must
be in the form of a permanent connection.
Ensure the appliance can be separated from
the power supply by an isolator that discon-
nects all poles with at least 3mm contact
separation.
- Maintain the minimum clearances to ensure
trouble-free operation of the appliance and
facilitate maintenance work.
- Maintenance work, such as checking the elec-
trical safety, must only be carried out by a
qualified contractor.
- We recommend regular inspection (to es-
tablish the current condition of the system),
and maintenance by a qualified contractor if
required (to return the system to its original
condition).
- Following disconnection from the power sup-
ply, parts of the appliance may remain ener-
gised for 2minutes until the inverter capaci-
tors have discharged.
- Never interrupt the power supply, even out-
side the heating season. The system's active
frost protection is not guaranteed if the power
supply is interrupted.
- If the heat pump is completely switched off
and there is a risk of frost, drain the system
on the water side.

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 Relevant documents
Instructions for the WPM heat pump manager
Operating and installation instructions for system
components
1.2 Safety instructions
1.2.1 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.
1.2.2 Symbols, type of risk
 
Injury
Electrocution
1.2.3 Keywords
 
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.
!

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1.3 Other symbols in this documentation
Note
General information is identified by the adjacent symbol.
 Read these texts carefully.
 
Material losses
(appliance damage, consequential losses and environmen-
tal pollution)
Appliance disposal
 This symbol indicates that you have to do something. The ac-
tion you need to take is described step by step.
1.4 Units of measurement
Note
All measurements are given in mm unless stated oth-
erwise.
1.5 Standardised output data
Information on determining and interpreting the specified stand-
ardised output data.
1.5.1 EN 14511
The output data specifically mentioned in texts, diagrams and
technical datasheets has been calculated according to the test
conditions of the standard shown in the heading of this section.
However, there is a deviation from this norm in the output data for
air/water inverter heat pumps at source temperatures of > -7°C,
as this concerns partial load values. The associated percentage
weighting in the partial load range can be found in EN14825 and
EHPA quality label regulations.
Generally, the test conditions stated above will not fully match the
conditions found at the installation site of the system user.
Depending on the chosen test method and the extent to which
this method differs from the test conditions defined in the first
paragraph of this section, any deviations can be considerable.
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.
Confirmation of the specified output data can only be obtained if
the test conducted for this purpose is also performed in accord-
ance with the test conditions defined in the first paragraph of this
section.
2. Safety
2.1 Intended use
Observe the application limits listed 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 a non-do-
mestic environment, e.g. in a small business, as long as it is used
in the same way.
Any other use beyond that described shall be deemed inappropri-
ate. Observation of these instructions and of instructions for any
accessories used is also part of the correct use of this appliance.
2.2 Safety instructions
Observe the following safety instructions and regulations.
- Only qualified contractors may carry out the electrical work
and installation of this appliance.
- The qualified contractor is responsible for adherence
to all applicable regulations during installation and
commissioning.
- The appliance should only be operated once it is fully in-
stalled and all safety equipment has been fitted.
- Protect the appliance from dust and dirt during building
work.
!
WARNING Injury
The appliance may be used by children over 8 years of
age and persons with reduced physical, sensory or men-
tal capabilities or a lack of experience and expertise,
provided that they are supervised or they have been
instructed on how to use the appliance safely and have
understood the potential risks. Children must never play
with the appliance. Children must never clean the ap-
pliance or perform user maintenance unless they are
supervised.
!
WARNING Injury
 For safety reasons, only operate the appliance with
the casing closed.
!

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
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3. Appliance description
3.1 Properties
The appliance is an air | water heat pump that operates as a heat-
ing heat pump for outdoor installation. Heat is extracted from the
outdoor air at a low temperature level, and is then transferred to
the heating water at a higher temperature. The heating water can
be heated up to a flow temperature of 65°C.
The appliance is equipped with an electric emergency/booster
heater (NHZ). To safeguard heating operation and the provision
of high DHW temperatures, the electric emergency/booster heat-
er is activated as an emergency heater if the dual mode point is
undershot in mono mode operation. If the same thing happens in
mono energetic operation, the electric emergency/booster heater
is activated as a booster heater.
This appliance has further operational characteristics:
- Suitable for underfloor and radiator heating systems.
- Preferred for low temperature heating systems.
- Extracts heat from the outdoor air even at outside tempera-
tures of -20°C.
- Corrosion-protected, external casing made from hot-dipped
galvanised sheet steel plus stove-enamelled finish.
- Comprises all components and safety equipment required for
operation.
- Filled with non-combustible safety refrigerant.
Note
For centralised control of the heating system, you would
need the WPM heat pump manager.
3.2 Function
3.2.1 Heating
Heat is extracted from the outdoor air via the heat exchanger
(evaporator) on the air side. The evaporated refrigerant is com-
pressed by a compressor. This process requires electrical ener-
gy. At this point, the refrigerant is at a higher temperature level.
A further heat exchanger (condenser) transfers the heat to the
heating circuit. The refrigerant then expands again and the cycle
restarts from the beginning.
At air temperatures below approx. 7°C, the humidity in the air
condenses as hoarfrost on the evaporator fins. This hoarfrost is
automatically defrosted. Water created by this defrosting process
collects in the defrost pan and is drained off.
!
Material losses
During the defrost cycle, the fan is switched off and the
heat pump circuit is reversed. The heat required for de-
frosting is drawn from the buffer cylinder. For operation
without a buffer cylinder, observe the information in the
instructions for the WPM and parameter BUFFER OPERA-
TION in menu SETTINGS/ STANDARD SETTING. Otherwise
the heating water freezes under unfavourable conditions.
The heat pump automatically reverts to heating mode at the end
of the defrost cycle.
!
Material losses
In dual mode operation, return water from the second
heat generator may flow through the heat pump. Please
note that the return temperature must be no higher than
60°C.
3.2.2 Cooling
!
Material losses
The heat pump is not suitable for continuous, year-round
cooling.
 Observe the application limits (see chapter "Specifi-
cation/ Data table").
!
Material losses
In cooling mode, condensate can form when the dew
point temperature is undershot.
 Take suitable measures to prevent the formation of
condensate.
Rooms are cooled by reversing the heat pump circuit. Heat is
extracted from the heating water and the evaporator transfers
this heat to the outdoor air.
Area cooling and fan cooling require the installation of a remote
control unit (FEK/FET) in a reference room to capture the rel-
ative humidity and the room temperature as part of dew point
monitoring.
With fan cooling, it is also necessary to install a buffer cylinder.
Heat pump application limit
The heat pump is switched off if the outside temperature falls
below the selected lower application limit for cooling (COOLING
LIMIT parameter).
4. Settings
The system is operated exclusively via the WPM heat pump man-
ager.
 Please observe the instructions for the heat pump manager.

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5. Maintenance and care
!
Material losses
Maintenance work, such as checking the electrical safety,
may only be carried out by a qualified contractor.
A damp cloth is sufficient for cleaning all plastic and sheet metal
parts. Never use abrasive or corrosive cleaning agents.
Regularly check the condensate drain (visual inspection). Remove
any contaminants and blockages immediately.
1.
2.
1
D0000037831
1 Inspection port
!
Material losses
Keep the air discharge and intake apertures free from
snow and leaves.
Remove any leaves or other foreign bodies from the evaporator
fins periodically.
We recommend a regular inspection (to establish the current con-
dition of the system), and maintenance by a qualified contractor
as required (to restore the system to the ideal condition).
6. Troubleshooting
  
There is no hot
water or the
heating system
remains cold.
No power at the appliance. Check the fuses/MCBs in
your distribution board.
Replace the fuses/reset the
MCBs if required. Notify
your qualified contractor if
the fuses/MCBs blow/trip
again after switching the
system back on.
Water is leaking
from the appli-
ance.
The condensate drain may be
blocked.
Clean the condensate drain
as described in "Mainte-
nance and care".
Condensate is
collecting on the
outside of the
appliance.
The heat pump extracts heat
from the outdoor air in order
to heat the building. This can
cause the humidity in the
outdoor air to accumulate as
dew or frost on the cooled
heat pump casing. This is not
a defect.
The fan runs
when the
compressor is
switched off.
At outside temperatures below
10°C, the fan is regularly
started at the lowest speed
when the compressor is idle.
This prevents the evaporator
and fan from freezing or icing
up due to water draining
off. At temperatures above
the freezing point, the time
between two defrost cycles is
increased, thereby improving
overall efficiency.
The appliance
produces rhyth-
mic scraping or
grinding noises.
Ice has formed on the air
grille, on the fan blades or in
the air routing.
Call your qualified contrac-
tor (see chapter "Installa-
tion/ Troubleshooting/ Fan
noise").
Note
Even when the condensate is draining away correctly, it
is not unusual for water to drip from the appliance onto
the floor.
If you cannot remedy the fault, contact your qualified contractor.
To facilitate and speed up your request, provide the number from
the type plate. The type plate is located at the front top, on the
right or left-hand side of the casing.
Sample type plate
Montageanweisung beachten! Dichtheit geprüft! Made in Germany
*xxxxxxxxxxxxxxxxxx*
26_03_01_1736
1
1 Number on the type plate

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
7. Safety
Only a qualified contractor should carry out installation, commis-
sioning, maintenance and repair of the appliance.
7.1 General safety instructions
We guarantee trouble-free function and operational reliability only
if original accessories and spare parts intended for the appliance
are used.
7.2 Instructions, standards and regulations
Note
Observe all applicable national and regional regulations
and instructions.
The tested appliance conforms to IEC 61000-3-11.
The tested appliance conforms to IEC 61000-3-12.
8. Appliance description
The appliance offers frost protection for the connection lines. The
integral frost protection circuit starts the circulation pump in the
heat pump circuit automatically at a condenser temperature of
8°C, and thereby ensures circulation in all water-carrying sec-
tions. If the temperature inside the buffer cylinder drops, the heat
pump starts automatically no later than when the temperature
falls below +5°C.
8.1 Accessories
8.1.1 Required accessories
- WPM heat pump manager
8.1.2 Additional accessories
- FEK remote control
- FET remote control
- FE7 remote control
- HZB 1 ribbon heater
- HZB 2 ribbon heater
- STB-FB high limit safety cut-out for underfloor heating
systems
- SK 1 T-support
- WK 2 wall mounting bracket
- MK 1 mounting bracket
- AS-WP 1 connection set
- AS-WP 2 connection set
9. Preparation
!
D0000060163
The appliance is designed for siting in front of a wall. Observe the
minimum clearances. If the appliance is installed in an open space
or on a roof, protect the air intake side. Do this by erecting a wall
to shield it against the wind.
9.1 Sound emissions
The appliance is louder on the air intake and air discharge sides
than on the two enclosed sides. Take the following information
into account when selecting the installation location.
Note
For details regarding the sound power level, see chapter
"Specification / Data table".
- Lawn areas and shrubs help reduce the spread of noise.
- Noise propagation can also be reduced through dense pali-
sades or similar.
 Ensure that the entire appliance frame is in full contact
with the substrate. Uneven substrates can increase sound
emissions.
 Ensure that the air intake direction is the same as the dom-
inant wind direction. Air should not be drawn in against the
wind.
 Ensure that the air intake and air discharge are never direct-
ed towards noise-sensitive rooms of the house, e.g.bed-
rooms, or neighbouring houses.
 Avoid installation on large, echoing floor areas, e.g.tiled
floors.
 Avoid installation between reflective building walls. Reflect-
ing building walls can increase the noise level.

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9.2 Minimum clearances
≥2000
≥500
≥300
≥1000
≥800
D0000028299
 Maintain the minimum clearances to ensure trouble-free op-
eration of the appliance and facilitate maintenance work.
91_00_00_0036
 Never install the appliance in a recess. Two sides of the ap-
pliance must remain exposed.
!
Material losses
Please note that both the flow of outdoor air into the
appliance, and the flow of exhaust air from the appliance
must be unimpeded.
If the air intake and discharge of the appliance are ob-
structed by surrounding objects, this may cause a thermal
short circuit.
9.3 Preparing the installation location
!
WARNING Injury
The discharged cold air can cause condensation to be
formed in the vicinity of the air outlet.
 Ensure that no risk of slipping due to wet conditions
or ice formation occurs on adjacent footpaths and
driveways at low temperatures.
 Observe chapter "Sound emissions".
 Ensure that the appliance is accessible from all sides.
 Ensure that the substrate is level, even, solid and permanent.
 Provide a recess (space) in the base to enable supply lines to
be routed into the appliance from below.
9.4 Installing the supply lines
The supply lines are all electric cables plus the flow and return
lines.
- To facilitate connection to the appliance, we recommend
using flexible supply lines in the case of outdoor installation.
 Also protect all supply lines against humidity, damage and
UV radiation by means of a conduit.
 Use only weatherproof cables, e.g. NYY.
 Protect the flow and return lines against frost with sufficient
thermal insulation. The thermal insulation must be at least
twice as thick as the diameter of the pipe. Provide thermal
insulation in accordance with applicable regulations.
 Protect all pipe fixings and external wall ducts with anti-vi-
bration insulation.
Note
When routing the condensate hose, observe chapter "In-
stallation/ Condensate drain".
9.5 Siting
 When siting the appliance, observe the air discharge
direction.
 Position the appliance on the prepared substrate or on a
suitable support.

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9.5.1 Siting on foundations or an MK 1 mounting bracket
(WPL15AS| WPL15ACS only)
Note
Allow the conduits for the supply lines to protrude slightly
above the foundations. Ensure that no water can enter
the conduits.
Foundations with recess (WPL15AS| WPL15ACS)
750
1300
100
410
200
75
140
4
5
1
3
2
D0000034133
1 Air intake
2 Air discharge
3 Main wind direction
4 Supply line recess
5 Condensate drain recess (minimum diameter 70mm)
 Ensure that the foundations offer the necessary recess.
Foundations with recess (WPL20A| WPL20AC| WPL25A|
WPL25AS| WPL25AC| WPL25ACS)
750
1500
100
410
200
75
140
4
5
1
3
2
D0000028298
1 Air intake
2 Air discharge
3 Main wind direction
4 Supply line recess
5 Condensate drain recess (minimum diameter 70mm)
 Ensure that the foundations offer the necessary recess.
Installation on foundations
4
12
5
AB
C
3
D0000028297
A 100
B 300
C Depth of frost line
1 Heating flow
2 Heating return
3 Condensate drain conduit
4 Foundation
5 Gravel bed
Note
To secure the appliance against toppling over, it can also
be fixed to the foundations with screws.
 Use the accessories with which the appliance was
secured to the transport pallet.
D0000064201
 Hook two brackets respectively into the lateral slots on the
front and back. Ensure you are using the correct brackets for
the left and right hand slots respectively.
 Position the brackets so that the groove on the bracket is
hooked into the appliance.
 Secure the appliance to the foundations using the brackets
and suitable rawl plugs and screws. Do not use the screws
with which the appliance was secured to the transport pallet.



10 www.stiebel-eltron.com
MK 1 mounting bracket (WPL15AS | WPL15ACS only)
Note
The mounting bracket cannot be used in combination
with the connection sets (AS-WP1 and AS-WP2).
7
6
1
A
8
3
1
2
4
5
D0000060818
A Depth of frost line
1 Heating flow
2 Heating return
3 Conduit for supply lines
4 Foundation
5 Mounting bracket
6 Gravel bed
7 Condensate drain conduit
8 Condensate drain
9.5.2 T-support SK1
Note
 Install a ribbon heater when mounting on the wall
bracket or T-support (see chapter "Electrical connec-
tion/ Ribbon heater").
A
B
8
5
7
3
4
9
2
1
6
D0000050006
A Depth of frost line
B 300
1 Heating flow
2 Heating return
3 Conduit for supply lines
4 Foundation
5 T-support
6 Gravel bed
7 Condensate drain conduit
8 Condensate drain
9 Cover
 Observe the structural limits of the T-support used.
 See the dimensioned connection drawing for the correct
spacing between holes (see chapter "Specification/ Dimen-
sions and connections").
9.5.3 WK 2 wall mounting bracket
Note
 Install a ribbon heater when mounting on the wall
bracket or T-support (see chapter "Electrical connec-
tion/ Ribbon heater").
Note
To prevent disturbance due to structure-borne noise
transmission, never install the wall mounting bracket on
the external walls of living areas or bedrooms.
 Install the wall mounting bracket on a garage wall,
for example.



www.stiebel-eltron.com 11
≥300
1
2
3
4
5
D0000058719
1 Heating flow
2 Heating return
3 Condensate drain
4 Condensate drain conduit
5 Wall mounting bracket
 Observe the structural limits of the wall mounting bracket
used.
 See the dimensioned connection drawing for the correct
spacing between holes (see chapter "Specification/ Dimen-
sions and connections").
9.6 WPM heat pump manager
A WPM heat pump manager is required to operate the appliance.
This controls the entire heating system.
 Observe the WPM installation instructions during installation.
9.7 Buffer cylinder
!
Material losses
A buffer cylinder with diffusion-proof insulation is es-
sential to enable cooling by means of fan convectors. The
emergency/booster heater must be connected.
We recommend the use of a buffer cylinder to ensure trouble-free
appliance operation.
The buffer cylinder provides hydraulic separation of the volume
flows in the heat pump circuit and heating circuit, and also serves
as an energy source for defrosting.
 For operation without a buffer cylinder, observe the details
in chapter "Minimum flow rate with individual room control
via remote control in systems without buffer cylinder".
9.8 Preparing the electrical installation
WARNING Electrocution
Carry out all electrical connection and installation work
in accordance with national and regional regulations.
WARNING Electrocution
The connection to the power supply must be in the form
of a permanent connection. Ensure the appliance can be
separated from the power supply by an isolator that dis-
connects all poles with at least 3mm contact separation.
This requirement can be met by contactors, isolators,
fuses, etc.
!
Material losses
The specified voltage must match the mains voltage. Ob-
serve the type plate.
!
Material losses
Provide separate fuses/MCBs for the three power circuits,
i.e. those of the appliance, the control unit and the elec-
tricemergency/booster heater.
 Use cables with the relevant cross-sections. Observe the ap-
plicable national and regional regulations.


 
1x C 20 A Compressor
(1-phase)
WPL 15 AS
WPL 15 ACS
2.5mm² when routing above the surface
4.0mm² when routing in a wall
1x C 35A Compressor
(1-phase)
WPL 25AS
WPL 25ACS
6.0mm² when routing in a wall
3x C 16 A Compressor
(3-phase)
WPL20A
WPL20AC
WPL25A
WPL25AC
2.5mm²
2x B 16 A Electric emergen-
cy/booster heater
WPL15AS
WPL15ACS
WPL25AS
WPL25ACS
2.5mm²
3x B 16 A Electric emergen-
cy/booster heater
WPL20A
WPL20AC
WPL25A
WPL25AC
2.5mm²
1x B 16 A Control unit 1.5mm²
The electrical data can be found in the chapter "Specification".
You require a screened J-Y (St) 2x2x0.8mm² cable as a bus cable.
Note
The appliance includes an inverter for the variable speed
compressor. In the event of a fault, inverters can cause
DC residual currents. If RCDs are provided, they must be
type B AC/DC-sensitive.
A DC residual current can block type A RCDs.
 Ensure that the appliance power supply is discon-
nected from the distribution board.



12 www.stiebel-eltron.com
10. Installation
Note
The device is designed in such a way that it can be po-
sitioned and connected without removing the cover or
side panels.
10.1 Transport
 When transporting the appliance, be aware of its centre of
gravity.
- The centre of gravity is in the area where the compressor is
located.
 Protect the appliance against heavy impact during transport.
 Use the recessed grips provided at the sides.
D0000071298
- If the appliance needs to be tilted during transport, this must
only be for a short time and it must only be tilted on one of
its longitudinal sides. When transporting the appliance, en-
sure the compressor is on the upper appliance side.
- The longer the appliance is tilted, the greater the distribution
of refrigerant oil inside the system.
 Wait approximately 30minutes before starting the appliance
after it has been tilted.
10.2 Heating water connection
!
Material losses
The heating system to which the heat pump is connected
must be installed by a qualified contractor in accordance
with the water installation drawings that are part of the
technical guide.
To facilitate connection to the heating system, push-fit connectors
are enclosed with the appliance (see chapter "Fitting the push-fit
connectors").
 Before connecting the heat pump, flush the pipework thor-
oughly with suitable water. Foreign bodies, such as welding
pearls, rust, sand or sealant can impair the operational relia-
bility of the heat pump.
 Connect the heat pump on the heating side. Check for
tightness.
 Ensure that the heating flow and return are connected
correctly.
 Provide thermal insulation in accordance with applicable
regulations.
 When sizing the heating circuit, observe the internal pressure
differential (see chapter "Specification/ Data table").
10.3 Flow and return connection
!
Material losses
In cooling mode, condensate can form when the dew
point temperature is undershot.
 Take suitable measures to prevent the formation of
condensate.
26_03_01_1871
2
1
3
4
1 Heating flow
2 Heating return
3 Drain
4 Ventilation
 Connect the heat pump to the heating circuit. Check for
tightness.
10.4 Fitting the push-fit connectors
Note
The plastic push-fit connectors are not suitable for instal-
lation in the DHW line or the solar circuit.
 Install the push-fit connectors only in the heating
circuit.
!Material losses
Tighten the screw cap of the push-fit connector by hand.
Never use a tool.
!Material losses
Support sleeves are required when using plastic pipes.
How the push-fit connectors work
The push-fit connectors are equipped with a retainer with stain-
less steel serrations and an O-ring for sealing. The push-fit con-
nectors also have a "twist and secure" function. Simply turning
the screw cap by hand will secure the pipe in the connector and
push the O-ring against the pipe to seal it.



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Making the push-fit connection
The connector must be in its relaxed position before the pipe is
inserted. In this position, there is a small gap between the screw
cap and main body.
26_03_01_0693
3
1
24
1 Retainer
2 Screw cap
3 Gap between screw cap and main body
4 Main body
26_03_01_0693
Pipe Ø 28 mm
Depth of insertion A 44mm
!Material losses
Pipe ends must be deburred.
 Always use a pipe cutter to trim pipes.
 Push the pipe past the O-ring into the push-fit connector
until it reaches the prescribed insertion depth.
 Tighten the screw cap by hand against main body as far as it
will go. This secures the push-fit connection.
Undoing the push-fit connection
If the push-fit connectors later need to be undone, proceed as
follows:
 Turn the screw cap anti-clockwise until there is a narrow gap
of approx. 2mm. Press the retainer back with your fingers
and hold on to it.
 Pull out the inserted pipe.
26_03_01_0693
10.5 Oxygen diffusion
!
Material losses
Avoid open vented heating systems and underfloor
heating systems with plastic pipes that are permeable
to oxygen.
In underfloor heating systems with plastic pipes that are per-
meable to oxygen and in open vented heating systems, oxygen
diffusion may lead to corrosion on the steel components of the
heating system (e.g. on the indirect coil of the DHW cylinder, on
buffer cylinders, steel radiators or steel pipes).
 With heating systems that are permeable to oxygen, separate
the heating system between the heating circuit and the buff-
er cylinder.
!
Material losses
The products of corrosion (e.g. rusty sludge) can set-
tle in the heating system components, which may re-
sult in a lower output or fault shutdowns due to reduced
cross-sections.
10.6 Filling the heating system
Carry out a fill water analysis before filling the system. This analy-
sis may, for example, be requested from the relevant water supply
utility.
!
Material losses
To avoid damage as a result of scaling, it may be neces-
sary to soften or desalinate the fill water. The fill water
limits specified in chapter "Specification/ Data table"
must always be observed.
 Recheck these limits 8-12weeks after commission-
ing, every time the system is topped up and during
the annual service.
Note
With a conductivity >1000μS/cm, desalination treatment
is recommended in order to avoid corrosion.
Note
If you treat the fill water with inhibitors or additives, the
same limits apply as for desalination.
Note
Suitable appliances for water softening and desalinating,
as well as for filling and flushing heating systems, can be
obtained from trade suppliers.
 Fill the heating system via the drain (see chapter "Specifica-
tion/ Dimensions and connections").
 After filling the heating system, check the connections for
leaks.



14 www.stiebel-eltron.com
10.6.1 Venting the heating system
 Vent the pipework carefully.
D000035306
1
1 Ventilation
 Vent the pipework by activating the ventilation.
10.7 Minimum flow rate
The minimum flow rate and the defrost energy must always be
assured (see chapter "Specification/ Data table").
10.8 Setting the flow rate on the heating side
!
Material losses
For operation without a buffer cylinder, it is essential
that the electric emergency/booster heater (NHZ) is con-
nected.
The appliance is designed in such a way that no buffer cylinder
is required in conjunction with appropriately sized area heating
systems.
Installations with several heating circuits require a buffer cylinder
to be used.
The setting is made in heat pump mode. In order to do this, firstly
make the following settings:
 Temporarily remove the fuse from the electric emergency/
booster heater to isolate the emergency/booster heater from
the power supply. Alternatively, switch OFF the second heat
generator.
 Operate the appliance in heating mode.
In combination with the HM hydraulic module
Note
You can enable spread control in combination with the
HMhydraulic module (see menu “COMMISSIONING/
HEATING/ SPREAD CONTROL).
When spread control is disabled, the heat pump regulates
to the set pump rate and a fixed flow rate.
The flow rate is set automatically via the self-regulating system
(see menu "COMMISSIONING/ HEATING/ SPREAD CONTROL/
STANDBY PUMP RATE" in the heat pump manager).
In heat pump mode a fixed spread between the heat pump flow
and return is set (see menu "COMMISSIONING/ HEATING/ SPREAD
CONTROL" in the heat pump manager).
Checking the flow rate
 Set parameter STANDBY PUMP RATE to 100%.
 Set buffer operation to OFF.
 If no buffer cylinder is installed, close all controllable heating
circuits.
 The current flow rate can be called up in the menu "INFO/
INFO HEAT PUMP/ PROCESS DATA" under "WP WATER FLOW
RATE".
 Compare the value with the specification (see chapter "Speci-
fication/ Data table").
 If the specified flow rate is not met, take suitable measures
to achieve the flow rate.
 If no buffer cylinder is installed, reopen all controllable heat-
ing circuits.
 Reset the parameters to their original values.
10.8.1 Minimum flow rate with individual room control via
remote control in systems without buffer cylinder
For systems without a buffer cylinder, in the "SETTINGS/ HEAT-
ING/ STANDARD SETTING" menu, set the "BUFFER OPERATION"
parameter to "OFF".
In such cases, one or more heating circuits in the heating system
must be left open. Ensure the minimum flow rate (see "Specifica-
tion/ Data table") by means of the relevant open heating circuits
(see table "Sizing recommendation for the underfloor heating
system in the lead room").
Note
The table applies if individual room control is installed.
Sizing recommendation for the underfloor heating system in the
lead room:
!
Material losses
A buffer cylinder with diffusion-proof insulation is essen-
tial to enable cooling by means of fan convectors.



www.stiebel-eltron.com 15

rate

-






floor area
-


floor area
-

 lm²  m² 
WPL 15 AS 700 16 21 3x70 21 2x70
WPL 15 ACS 700 16 21 3x70 21 2x70
WPL20A 1000 29 28 4x70 32 3x70
WPL20AC 1000 29 28 4x70 32 3x70
WPL 25 A 1000 29 28 4x70 32 3x70
WPL 25 AS 1000 29 28 4x70 32 3x70
WPL 25 AC 1000 29 28 4x70 32 3x70
WPL 25 ACS 1000 29 28 4x70 32 3x70










WPL 15 AS No 100 100 Yes
WPL 15 ACS No 100 100 Yes
WPL20A No 100 100 Yes
WPL20AC No 100 100 Yes
WPL 25 A No 100 100 Yes
WPL 25 AS No 100 100 Yes
WPL 25 AC No 100 100 Yes
WPL 25 ACS No 100 100 Yes
 Install the open heating circuit(s) in the lead room (room
where the external programming unit of the heat pump con-
trol unit is installed, such as in the living room). The individ-
ual room can then be controlled either with the external pro-
gramming unit or indirectly by adjusting the heating curve or
the room influence.
 Fully open the heating circuit(s) in the lead room.
 Close all other heating circuits.
 If an overflow valve has been installed in the heating system,
fully close this overflow valve in order to determine the mini-
mum flow rate.
In combination with a hydraulic module, cylinder and hydraulic
module or integral cylinder:
 Under menu item "COMMISSIONING/ HEATING" the param-
eter "HEATING CIRC PUMP RATE" (heating circuit pump rate)
such that the minimum flow rate required for system opera-
tion is assured (see chapter "Specification/ Data table").
If the appliance is operated on its own with a WPM:
 Set the heating circuit pump so that the minimum flow rate
required to operate the system is safeguarded.
The current flow rate can be called up in the menu "INFO/ HEAT
PUMP INFO/ PROCESS DATA" under "WP WATER FLOW RATE".
10.8.2 Minimum flow rate for systems with a buffer cylinder
When using a buffer cylinder, in menu "SETTINGS/ HEATING/
STANDARD SETTINGS", set parameter "BUFFER OPERATION" to
"ON".
In combination with a hydraulic module, cylinder and hydraulic
module or integral cylinder, and with spread control disabled:
 In menu "COMMISSIONING/ HEATING", set parameter "HEAT-
ING CIRC PUMP RATE" so that the nominal flow rate required
for system operation is assured (see chapter "Specification/
Data table").
If the appliance is operated on its own with a WPM:
 Set the buffer charging pump so that the nominal flow rate
required for system operation is assured.
The current flow rate can be called up in the menu "INFO/ HEAT
PUMP INFO/ PROCESS DATA" under "WP WATER FLOW RATE".
10.9 Condensate drain
A condensate drain connector is factory-fitted to the defrost pan
to enable any condensate to drain off.
26_03_01_1868
1
1 Condensate drain
 Observe chapter "Electrical connection/ Ribbon heater".
 If the appliance is sited on foundations, the condensate drips
freely into the condensate drain pipe.
 If the appliance is mounted on a bracket or T-support, attach
a condensate hose to the condensate drain.
 Protect the condensate hose against frost with sufficient
thermal insulation.



16 www.stiebel-eltron.com
!
Material losses
Ensure the condensate hose is not kinked. Route the hose
with a slope.
 After routing the condensate hose, check that the condensate
can drain correctly.
10.10 External second heat generator
For dual mode systems, always connect the heat pump into the
return of the second heat generator (e.g. oil boiler).
10.11 High limit safety cut-out for underfloor heating
systems
!
Material losses
In order to prevent excessively high flow temperatures
in the underfloor heating system causing damage in the
event of a fault, we always recommend using a high limit
safety cut-out to limit the system temperature.
11. Electrical connection
WARNING Electrocution
 Before working on the appliance, isolate it from the
power supply at the control panel.
The connection must only be made by a qualified contractor and
in accordance with these instructions.
You must have permission to connect the appliance from the rel-
evant power supply utility.
Note
Observe the operating and installation instructions of the
WPM heat pump manager.
The terminals are located in the terminal area of the appliance.
Follow the instructions in the chapter "Preparation/ Preparing
the electrical installation".
 For all connections, use appropriate cables in accordance
with local regulations.
11.1 Access to the terminal area
D0000035356D0000035358
 Push the cover upwards.



www.stiebel-eltron.com 17
D0000035363
1 2
1 Strain relief
2 Terminal area
 Route cables and leads through the strain relief fittings.
If space behind the appliance is limited, the terminal area can be
folded out.
D0000035380
 Undo the screw on the terminal area.
D0000035382
 Pivot the terminal area to the side.
D0000075146
 Fix the terminal area in place with the locking mechanism.
 Connect the electric emergency/booster heater if you want to
utilise the following appliance functions:
-
tion


Mono energetic op-
eration
If the dual mode point is undershot, the electric emer-
gency/booster heater safeguards both the heating oper-
ation and the provision of high DHW temperatures.
Emergency mode If the heat pump shuts down due to a fault, the heating
output is covered by the electric emergency/booster
heater.
Heat-up program
(only for underfloor
heating systems)
Where return temperatures are <25°C, the electric
emergency/booster heater must provide the necessary
heat for screed drying.
With such low system temperatures, the heat for screed
drying must not be provided by the heat pump, other-
wise the frost protection of the appliance can no longer
be guaranteed during the defrost cycle.
When the heat-up program has ended, the electric
emergency/booster heater can be disconnected if it is
not required for appliance operation.
Please note that during the heat-up program, emergency
mode is not available.
Pasteurisation
mode
The electric emergency/booster heater starts automat-
ically when pasteurisation mode is active. The DHW is
then regularly heated to 60°C to protect it against the
growth of legionella bacteria.



18 www.stiebel-eltron.com
11.2 WPL 15 AS| WPL15ACS
 Connect the cables according to the following diagram.
BUS
X2
L
H
T
„+“
X5 / DHC X3 / WP X4 / Steuerung
N LL N L N L
ON
-
ERR
N
3,0 kW L N PE
3,2 kW L N PE
6,2 kW L N L N PE
1/N/PE~230/50
C 32A
1/N/PE~230/50
C 16A
1/N/PE~230/50
C 20A
D0000037825
1
1 Earth terminal for screening the LV lead
X2 
BUS High H
BUS Low L
BUS earth
BUS "+" (is not connected)
X3 
L, N, PE
X4 
-
ON
ERR
Power supply: L, N, PE
X5 
L, N, L, N, PE
 
3.0kW L N PE
3.2kW L N PE
6.2kW L N L N PE
 Earth the LV lead by inverting the screen over the external
sheath and clamping it under the earth terminal.
 Then check that the strain relief fittings are working as
intended.
11.3 WPL20A| WPL20AC| WPL25A| WPL25AC
 Connect the cables according to the following diagram.
X5 / DHC X3 / WP X4 / Steuerung
L2 L3L1 N L2 L3L1 N L
ON
-
ERR
N
2,6 kW L1 N PE
3,0 kW L2 N PE
3,2 kW L3 N PE
5,6 kW L1 L2 N PE
5,8 kW L1 L3 N PE
6,2 kW L2 L3 N PE
8,8 kW L1 L2 L3 N PE
3/N/PE~400/50
C 16A
1/N/PE~230/50
C 16A
3/N/PE~400/50
C 16A
BUS
X2
L
H
T
„+“
26_03_01_1859
1
1 Earth terminal for screening the LV lead
X2 
BUS High H
BUS Low L
BUS earth
BUS "+" (is not connected)
X3 
L1, L2, L3, N, PE
X4 
-
ON
ERR
Power supply: L, N, PE
X5 
L1, L2, L3, N, PE
 
2.6kW L1 PE
3.0kW L2 PE
3.2kW L3 PE
5.6kW L1 L2 PE
5.8kW L1 L3 PE
6.2kW L2 L3 PE
8.8kW L1 L2 L3 PE
 Earth the LV lead by inverting the screen over the external
sheath and clamping it under the earth terminal.
 Then check that the strain relief fittings are working as
intended.



www.stiebel-eltron.com 19
11.4 WPL25AS| WPL25ACS
 Connect the cables according to the following diagram.
BUS
X2
L
H
T
„+“
X5 / DHC X3 / WP X4 / Steuerung
N LL N L N L
ON
-
ERR
N
3,0 kW L N PE
3,2 kW L N PE
6,2 kW L N L N PE
1/N/PE~230/50
C 32A
1/N/PE~230/50
C 16A
1/N/PE~230/50
C 20A
D0000037825
1
1 Earth terminal for screening the LV lead
X2 
BUS High H
BUS Low L
BUS earth
BUS "+" (is not connected)
X3 
L, N, PE
X4 
-
ON
ERR
Power supply: L, N, PE
X5 
L, N, L, N, PE
 
3.0kW L N PE
3.2kW L N PE
6.2kW L N L N PE
 Earth the LV lead by inverting the screen over the external
sheath and clamping it under the earth terminal.
 Then check that the strain relief fittings are working as
intended.
11.5 Closing the terminal area
D0000035356
1
2
1 Serrated washer
2 Screw
 Secure the cover with the screw and serrated washer.
 Connect the following components to the heat pump manag-
er in accordance with the technical guides:
- Circulation pump for the heat consumer side
- Outside temperature sensor
- Return sensor (only for operation with buffer cylinder)
11.6 Ribbon heater
A ribbon heater (see chapter "Installation/ Appliance description/
Accessories/ Further accessories") can be fitted to the condensate
pan and the condensate hose.
 Install a ribbon heater when mounting on the wall bracket or
T-support.
When installing on foundations or the mounting bracket, we rec-
ommend installing a ribbon heater if the routing of the condensate
hose means it is at risk of frost or is fully exposed to the elements.
Access to the terminal area
26_03_01_1544
 Remove the cover.



20 www.stiebel-eltron.com
A.
1
D0000035975
1 Electrical connection for ribbon heater
 Guide the ribbon heater through the appliance.
D0000033168
 Guide the ribbon heater into the condensate drain pipe.
B.
D0000035976
 Make the electrical connection for the ribbon heater.

Power supply: L, N, PE
Closing the terminal area
26_03_01_1867
 Position the cover on the appliance.
 Secure the cover with the four screws.
12. Commissioning
A WPM heat pump manager is required to operate the appliance.
All necessary adjustments prior to and during operation are made
on this device.
Only qualified contractors may make the settings in the heat pump
manager commissioning report, commission the appliance and
instruct the owner in its use.
Carry out commissioning in accordance with these operating and
installation instructions, and the instructions for the heat pump
manager. Our customer support can assist with commissioning,
which is a chargeable service.
Where this appliance is intended for commercial use, the rules of
the relevant Operational Safety Ordinance must be observed at
commissioning. For further details, check with your local author-
ising body (e.g. TÜV).
12.1 Checks before commissioning
Before commissioning, check the following:
12.1.1 Heating system
- Have you filled the heating system to the correct pressure
and opened the quick-action air vent valve?
12.1.2 Temperature sensors
- Have you correctly positioned and connected the outside
temperature sensor and the return temperature sensor (in
connection with a buffer cylinder)?