STIEBEL ELTRON DHE 18 AU Instruction Manual

OPERATION AND INSTALLATION
Instantaneous water heater with full electronic control
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CONTENTS | SPECIAL INFORMATION
SPECIAL INFORMATION
OPERATION
1. General information �����������������������������������������3
1.1 Safety instructions����������������������������������������������� 3
1.2 Other symbols in this documentation ����������������������� 3
1.3 Units of measurement ������������������������������������������ 3
2. Safety����������������������������������������������������������3
2.1 Intended use������������������������������������������������������ 3
2.2 General safety instructions ����������������������������������� 3
2.3 CE designation ��������������������������������������������������� 4
2.4 Test symbols ������������������������������������������������������ 4
3. Appliance description���������������������������������������4
4. Settings and displays ����������������������������������������5
4.1 User interface ���������������������������������������������������� 5
4.2 Setting the temperature���������������������������������������� 5
4.3 Following an interruption of the water supply ������������ 5
4.4 Economy monitor selection������������������������������������ 6
4.5 Appliance settings ���������������������������������������������� 6
5. Cleaning, care and maintenance ���������������������������8
6. Troubleshooting ����������������������������������������������8
INSTALLATION
7. Safety����������������������������������������������������������9
7.1 General safety instructions ������������������������������������ 9
7.2 Instructions, standards and regulations �������������������� 9
8. Appliance description ���������������������������������������9
8.1 Standard delivery������������������������������������������������ 9
9. Preparations ��������������������������������������������������9
9.1 Installation site��������������������������������������������������� 9
10. Installation�������������������������������������������������� 10
10.1 Standard installation������������������������������������������� 10
10.2 Completing the installation����������������������������������� 12
10.3 Installation options��������������������������������������������� 13
11. Commissioning ��������������������������������������������� 15
11.1 Initial start-up��������������������������������������������������� 15
11.2 Recommissioning����������������������������������������������� 15
12. Service mode ����������������������������������������������� 15
13. Shutting down the system �������������������������������� 16
14. Troubleshooting �������������������������������������������� 16
15. Maintenance ������������������������������������������������ 18
16. Specification ������������������������������������������������ 18
16.1 Dimensions and connections��������������������������������� 18
16.2 Wiring diagram ������������������������������������������������� 19
16.3 DHW output������������������������������������������������������ 19
16.4 Application areas / conversion table ����������������������� 19
16.5 Pressure drop ��������������������������������������������������� 19
16.6 Fault conditions ������������������������������������������������� 20
16.7 Data table �������������������������������������������������������� 20
WARRANTY | ENVIRONMENT AND RECYCLING
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.
- Ensure the appliance can be separated from the
power supply by an isolator that disconnects all
poles with at least 3mm contact separation.
- Secure the appliance as described in chapter "In-
stallation/ Installation".
- Observe the maximum permissible pressure (see
chapter "Specification/ Data table").
- Drain the appliance as described in chapter "In-
stallation/ Maintenance/ Draining the appliance".

OPERATION
General information
ENGLISH
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OPERATION
1. General information
The chapter "Operation" is intended for appliance users and qual-
ified 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 or scalding
1.1.3 Keywords
KEYWORD Meaning
DANGER Failure to observe this information will result in serious
injury or death.
WARNING Failure to observe this information may result in serious
injury or death.
CAUTION Failure to observe this information may result in non-seri-
ous or minor injury.
1.2 Other symbols in this documentation
Note
Notes are bordered by horizontal lines above and below
the text. General information is identified by the symbol
shown on the left.
 Read these texts carefully.
Symbol
!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.
1.3 Units of measurement
Note
Unless specified otherwise, all dimensions are given in
mm.
2. Safety
2.1 Intended use
This appliance is intended for domestic use. It can be used safely
by untrained persons. The appliance can also be used in a non-do-
mestic environment, e.g. in a small business, as long as it is used
in the same way.
Any other use beyond that described shall be deemed inappropri-
ate. Observation of these instructions and of instructions for any
accessories used is also part of the correct use of this appliance.
This pressurised appliance is suitable for heating domestic hot
water or for reheating preheated water. The appliance can supply
one or more draw-off points.
2.2 General safety instructions
CAUTION Burns
During operation, the tap can reach temperatures in ex-
cess of 60 °C.
There is a risk of scalding at outlet temperatures in ex-
cess of 43 °C.
!
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.

OPERATION
Appliance description
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Where children or persons with limited physical, sensory or men-
tal abilities are allowed to use this appliance, we recommend a
permanent temperature limit. The limit can be set by you or a
qualified contractor:
- Childproofing adjustable by the user
- Anti-scalding protection adjustable by the qualified
contractor
!
Material losses
Protect the appliance and its tap against frost.
2.3 CE designation
The CE designation shows that the appliance meets all essential
requirements according to the:
- Low Voltage Directive
- Electromagnetic Compatibility Directive
The maximum permissible mains impedance is indicated in
chapter "Specification".
2.4 Test symbols
See type plate on the appliance
Information for Australia/New Zealand:
Installation complies with standard AS/NZS 3500.4.
3. Appliance description
This appliance with full electronic control and output matching
keeps the outlet temperature constant. The water is heated by the
electronic control unit with motorised valve to precisely the select-
ed temperature. This occurs regardless of the inlet temperature.
DHW temperature
The DHW outlet temperature can be variably adjusted. The
selected temperature is displayed.
Heating system
The bare wire heating system has a pressure-tested copper casing.
The heating system is suitable for hard and soft water areas; it
has low susceptibility to scale build-up. This system ensures rapid
and efficient DHW availability.
Note
The appliance is equipped with an air detector that large-
ly prevents damage to the heating system. If, during op-
eration, air is drawn into the appliance, the heater shuts
down automatically for one minute, thereby protecting
the heating system.
Display backlighting
The display features two-tone backlighting (green/ amber).
Efficiency display
Green ECO backlighting indicates that the appliance is operating
in a particularly economical way
- when the output is less than 80%
- when the maximum output is less than 80% while the inlet
temperature is higher than 35°C
- when the maximum output is less than 80% while the ECO
function is switched on
Under all other operating conditions, the backlighting is amber.
Economy monitor
The appliance has an economy monitor. This is activated by press-
ing the appropriate key. Advertisements:
- Energy savings*
- Water savings*
- CO2savings*
- Energy consumption
- Water consumption
* Compared to hydraulic instantaneous water heaters. Calculation
for a 3-person household with individual DHW requirements and
usable energy requirements subject to VDI 2067. Electricity and
water costs can be programmed individually.

OPERATION
Settings and displays
ENGLISH
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4. Settings and displays
4.1 User interface
D0000033114
1
2
3
4
5
69
78
10
1 Temperature selector
2 Scalding risk LED
3 Memory key
4 Menu key
5 Additional value display
6 Heating output display
7 Temperature display
8 Service symbol
9 Fault symbol
10 Economy monitor information key
When the appliance is delivered the backlighting is set so that
the screen is illuminated automatically as soon as you operate
the selector or a key, or the appliance heats. If the selector or a
key is not pressed or the appliance does not heat for 30seconds,
the backlighting switches off. You can also set the illumination to
be on constantly.
Display symbols
26�02�02�1230�
1 2 3 4 5 6
1 Wellness shower programs
2 Automatic water volume control
3 ECO
4 Childproofing
5 Additional value display
6 Time
4.2 Setting the temperature
26�02�02�1321�
32
1
1 Temperature setting 20 - 60°C in steps of 0.5°C,
OFF = heating system switched off
2 Programmed temperature selection
3 Economy monitor selection
You can store a preferred temperature with memory key M.
 Select a preferred temperature.
 Press the M key for 2 seconds. The temperature display flash-
es once to confirm.
Inlet temperature information
If the inlet temperature is higher than the preferred temperature,
e.g. if water has been preheated by solar energy, then the tem-
perature display flashes and the second display indicates the inlet
temperature. No further heating of the water occurs.
D0000033113
2
1
3
1 Temperature display flashes
2 Inlet temperature display
3 Scalding risk LED; red LED when the temperature setting >
43 °C
Recommended setting for operation with a thermostatic valve
Set the temperature at the appliance to 60°C.
4.3 Following an interruption of the water supply
!
Material losses
Following an interruption of the water supply the appli-
ance must be recommissioned by carrying out the follow-
ing steps, in order to prevent the destruction of the bare
wire heating system.
 Disconnect the appliance from the power supply by
removing the fuses/tripping the MCBs.
 Open the tap for one minute until the appliance and
its upstream cold water inlet line are free of air.
 Switch the mains power back ON again.

OPERATION
Settings and displays
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4.4 Economy monitor selection
Example menu structure with currency in euros (Eur)
2 sec.
Reset
M
2 sec.
Reset
M
2 sec.
Reset
M
2 sec.
Reset
M
2 sec.
Reset
M
1
2
3
4
5
2 sec. / time-out 10 sec.
D0000032904
1 Energy saving
The energy saving in euros (Eur) in comparison to hydraulic in-
stantaneous water heaters is calculated and displayed.
2 Water saving
The water saving in euros (Eur) in comparison to hydraulic instan-
taneous water heaters is calculated and displayed.
3 CO2 emissions
The CO2 saving in kg in comparison to hydraulic instantaneous
water heaters is calculated and displayed.
4 Amount of energy
The amount of energy consumed in kWh is displayed.
5 Water consumption
The amount of water consumed in m³ is displayed.
4.5 Appliance settings
Key to symbols
Press once START menu
Press once Change menu
Hold for 2seconds END
Change settings/ scanning
Menu structure
Eur
Eur
0_00...9999 €/kWh
cur
0_00...9999 cur/kWh
Eur
0_00...9999 €/m³
cur
0_00...9999 €/m³
cur
OFF | 20 - 60 °C
OFF | 4 - 15 l/min
OFF | 1 | 2 | 3 | 4
OFF | 5 - 200 l
l/min
12:00
00:00 - 23:59
Auto
On
bernstein/amber
grün/green
OFF
OFF
OFF
OFF
l/min
Auto
100 %
1
2
3
4
5
6
7
8
13
100 %
2 sec. /
9
10
11
12
14
15
time-out 30 sec.
CO2
0...2000 g/kWh
M
0,22 cur/kWh
5,00 cur/m³
553 g/kWh
0,22 €/kWh
5,00 €/m³
D0000032902

OPERATION
Settings and displays
ENGLISH
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1 ECO water and energy saving function
The ECO function enables you to limit the flow rate to a maxi-
mum value.
ECO on = symbol on user interface
ECO off = no symbol on user interface
2 Childproofing
Childproofing allows you as a user to limit the adjustable temper-
ature at the appliance to a maximum value. In service mode, your
qualified contractor can also set a temperature for anti-scalding
protection (see chapter "Service mode"). This temperature then
acts as the upper limit of the setting range for childproofing.
3 Wellness shower programs
The Wellness shower program lets you choose from 4 different
shower programs.
WW = domestic hot water, KW = cold water
A Cold prevention
To strengthen the body, we recommend you finish off with
a cold shower; this will trigger a reflex in the body to warm
up.
3 min
WW
KW
B Winter pick-me-up
An invigorating end to a winter shower with a final warm-
up. - 10°C
WW
WW
3 min 10 sec 10 sec
10 sec 10 sec
C Summer fitness program
The quick contrast shower to increase fitness with a final
warm-up.
WW
KW
3 min
10 sec 10 sec
10 sec 10 sec
D Circulation program
Shower your arms and legs with cold water to boost
circulation. Spray from the hands and feet towards
the body. You can then repeat this process with warm
water.
WW
KW
3 min
20 sec 20 sec
30 sec 30 sec
4 Automatic water volume control
The automatic water volume control allows you to limit the volume
of water at a high flow rate. When the selected volume of water
is reached, the control automatically reduces the flow rate. The
preferred water temperature is maintained. The automatic water
volume control must be enabled on each occasion prior to filling
the bath. Example of filling a bath with 80 litres: When the bath
has been filled with 80 litres, the control automatically reduces
the flow rate to 4 l/min.
5 Flow rate
You have the option of displaying the flow rate or the time.
6 Setting the time
You have the option of displaying the time or the flow rate. You
can set a time from 00:00 h to 23:59 h. You will need to set the
time again following a power interruption.
7 Adjusting the backlighting
You are able to adjust the display backlighting. If you select "Auto"
the illumination will flash during the setting process.
- The backlighting switches on whenever the appliance heats
and with any operation of the user interface.
- If there is no operation for 30seconds the backlighting
switches off.
- If you select "On" the backlighting will remain on constantly.
8 Adjusting the green/amber brightness
You can adjust the brightness of both backlighting colours indi-
vidually.
9 Selecting the currency
Here you can select the currency you wish to display for the en-
ergy and water saving:
Eur = €
cur = any other currency
10 Setting the electricity tariff
Here you can enter your particular electricity tariff in Eur/kWh or
cur/kWh in order to calculate the energy saving.
11 Setting the water tariff
Here you can enter your particular water tariff in €/m³ or cur/m³
in order to calculate the water saving.
12 Setting the CO2 emissions value
The factory default for the CO2 emissions calculation is 553 g
CO2⁄kWh (source: "Reducing energy consumption and CO2 emis-
sions through electrical domestic hot water supply", 2011). You can
also set your own CO2 emissions value if required.
13 Resetting to factory defaults
 Press keys M and i simultaneously for 2 seconds.
The default settings can be found in the dashed box in the dia-
gram.
14 Menüpunkt
This parameter is not relevant to this version of the appliance. It
is not possible to adjust any settings.
15 Menüpunkt
This parameter is not relevant to this version of the appliance. It
is not possible to adjust any settings.

OPERATION
Cleaning, care and maintenance
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5. Cleaning, care and maintenance
 Never use abrasive or corrosive cleaning agents. A damp
cloth is sufficient for cleaning the appliance.
 Check the taps regularly. Limescale deposits at the spouts
can be removed using commercially available descaling
agents.
6. Troubleshooting
Fault Cause Remedy
The appliance will not
start despite the DHW
valve being fully open.
There is no mains volt-
age.
Check the fuse/MCB in
your fuse box/distribu-
tion panel.
The aerator in the tap
or the shower head is
scaled up or contami-
nated.
Clean and/or descale the
aerator or shower head.
The water supply has
been interrupted.
Vent the appliance and
the cold water inlet line
(see chapter "Commis-
sioning/ Restarting").
Cold water flows briefly
while hot water is being
drawn.
The air sensor detects air
in the water and briefly
switches the heater off.
The appliance restarts
automatically after
1minute.
Temperatures >43°C. Dynamic anti-scalding
protection is activated.
Dynamic anti-scalding
protection automatically
ceases 2minutes after
draw-off has ended.
If you cannot remedy the fault, notify your qualified contractor.
To facilitate and speed up your enquiry, please provide the serial
number from the type plate (000000-0000-000000):
No.: 000000-0000-000000
DHE ... AU
26�02�02�1125�

ENGLISH
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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 the original accessories and spare parts intended for the
appliance are used.
!
Material losses
Observe the maximum inlet temperature. Higher tem-
peratures may damage the appliance. You can limit the
maximum inlet temperature by installing a central ther-
mostatic valve.
7.2 Instructions, standards and regulations
Note
Observe all applicable national and regional regulations
and instructions.
- The protection rating IP 25 (hoseproof) can only be ensured
with a correctly fitted cable grommet.
- The specific electrical resistance of the water must not fall
below that stated on the type plate. In a linked water net-
work, observe the lowest electrical water resistance (see
chapter "Specification/ Application areas"). Your water
supply utility will advise you of the specific electrical water
resistance or conductivity.
8. Appliance description
8.1 Standard delivery
The following are delivered with the appliance:
- Mounting bracket
- Installation template
- 2 plugs
- 2 extensions
- 2 caps
- 2 tees
- 8 flat gaskets
- Strainer
- Plastic profile washer
- Plastic connection pieces/ installation aid
- Cover and back panel guides
9. Preparations
 Flush the water line thoroughly.
Taps/valves
 Use appropriate pressure-tested taps. Open taps are not
permitted.
A safety valve is not required.
Permissible water pipe materials
- Cold water inlet pipe:
Galvanised steel pipe, stainless steel pipe, copper pipe or
plastic pipe
- DHW outlet pipe:
Stainless steel pipe, copper pipe or plastic pipe
!
Material losses
If plastic pipework systems are used, take into account
the maximum inlet temperature and the maximum pres-
sure (see chapter "Specification/ Data table").
Flow rate
 Ensure that the flow rate (see chapter "Specification/ Data
table", On) for switching on the appliance is achieved.
 Increase the mains water pressure if the required flow rate is
not achieved with the draw-off valve fully opened.
Flexible water connection lines
 If the appliance is installed with flexible water connection
lines, ensure that the pipe bends do not become twisted.
Pipe bends have a bayonet fitting and are installed inside the
appliance.
 Secure the back panel with an additional screw at the
bottom.
9.1 Installation site
!
Material losses
Only install the appliance in rooms free from the risk of
frost.
 Always install the appliance vertically near the draw-off
point.
The appliance is suitable for undersink and oversink installations.
Note
Mount the appliance on a sufficiently load-bearing wall.

10 | DHE AU www.stiebel-eltron.com
INSTALLATION
Installation
Undersink installation
D0000034274
1
2
1 Cold water inlet
2 DHW outlet
Oversink installation
D0000034275
21
1 Cold water inlet
2 DHW outlet
10. Installation
10.1 Standard installation
- Electrical connection in the lower section of the appliance for
installation on unfinished walls
- Water connection for installation on finished walls
For further installation options, see chapter "Installation options".
26�02�02�0543
 Open the appliance.
26�02�02�1101
 Remove the back panel by pressing the two locking hooks
and pulling the lower part of the back panel forwards.
26�02�02�0810�
 Mount the wall mounting bracket.
Align the installation template based on the existing electrical
connection when marking out the drill holes (wall mounting and
lower back panel).
If you want to adapt the existing water connections, take the di-
mensions from the drawing when marking out the drill holes; see
chapter "Specification/ Dimensions and connections". In this case,
check beforehand that the electrical connection lies within one of
the areas marked on the installation template.
 Drill the holes and secure the mounting bracket with
2screws and 2rawl plugs (screws and rawl plugs are not
part of the standard delivery).
160
30
1
26�02�02�0824�
1 Installation aid
 Prepare the power cable.
Preparing the water connection
!
Material losses
Carry out all water connection and installation work in
accordance with regulations.

ENGLISH
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INSTALLATION
Installation
D0000041720
 Remove the caps from the tees.
 Fit the plugs and the extensions with gaskets.
D0000041721
 Fit the strainer in the tee for the cold water inlet.
!
Damage to the appliance and environment
The strainer must be fitted for the appliance to function.
 When replacing the appliance, check that the strain-
er is present.
D0000043265
 Fit the plastic profile washer.
Installing the appliance
1821 24
kW
26�02�02�0934�
 For easy installation, push the cable grommet of the upper
electrical connection into the back panel from behind.
 Remove the transport plugs from the water connections.
 Remove the fixing toggle from the upper part of the back
panel.
 Route the power cable through the lower cable grommet
from behind, until the power cable rests against the cable
sheath. Align the power cable.
If the cross-section is >6mm², enlarge the hole in the cable
grommet.
 Press the appliance over the threaded stud of the wall
mounting bracket. When doing so, push through the soft
seal in the back panel of the appliance. If necessary, use a
screwdriver.
 Push the fixing toggle on to the threaded stud of the wall
mounting bracket.
 Push the back panel of the appliance on to the wall. Turn the
fixing toggle 90° clockwise to lock the appliance in place.
D0000041723
 Screw the pre-assembled parts with flat gaskets to the cold
water and DHW pipes of the appliance.
 Fit the cold water inlet pipe and the DHW outlet pipe from
the pipework with flat gaskets to the extensions from the
appliance.
Making the electrical connection
WARNING Electrocution
Carry out all electrical connection and installation work
in accordance with relevant regulations.
WARNING Electrocution
Connection to the power supply is only permissible in the
form of a permanent connection in conjunction with the
removable cable grommet. 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.
WARNING Electrocution
Ensure that the appliance is earthed.
!
Damage to the appliance and environment
Observe the type plate. The specified voltage must match
the mains voltage.

12 | DHE AU www.stiebel-eltron.com
INSTALLATION
Installation
26�02�02�1122�
 Connect the power cable to the mains terminal (see chapter
"Specification/ Wiring diagram"). The specified voltage must
match the mains voltage.
Lower back panel installation
1
2
26�02�02�1080
1 Connection pieces delivered in the pack
2 Screw
 Cut open the lower part of the back panel (see illustration).
 Fit the lower back panel by bending it out at the sides and
guiding it over the pipes.
 Insert the connection pieces into the lower back panel from
behind.
 Click the lower back panel into place.
 Align the mounted appliance by loosening the fixing toggle,
aligning the power supply and back panel, and then re-tight-
ening the fixing toggle.
 Secure the lower back panel with a screw.
10.2 Completing the installation
 Open the shut-off valve in the cold water inlet line.
Fitting the sealing elements for the appliance cover
1
2
3
D0000040777
1 Pipe aperture
2 Cover guides
3 Back panel guides
!
Material losses
If you cut open the wrong knock-out in the appliance
cover by mistake, you must use a new appliance cover.
 Cleanly cut or break out the knock-out openings in the appli-
ance cover. If necessary, use a file.
Note
You can compensate for a slight connection pipe offset
using the tabs on the cover guides. If the connection pipes
are offset, do not fit any back panel guides.
 When installing connection pipes that are not offset, break
off the tabs on the cover guides.
 Click the cover guides into place in the pipe apertures.
 Position the back panel guides on the extensions. Push them
together. Then push the guides until they are resting against
the back panel.

ENGLISH
www.stiebel-eltron.com DHE AU| 13
INSTALLATION
Installation
10.3 Installation options
- Electrical connection from above on unfinished walls
- Electrical connection for finished walls
- Large cross-section for electrical connection from below
- Water installation on unfinished walls
- Wall mounting bracket when replacing an appliance
- Installation with offset tiles
- Pivoting appliance cover
- Operation with preheated water
Electrical connection from above on unfinished walls
26�02�02�1123�
 Cut open the cable grommet for the power cable.
 Push down the locking hook to secure the mains terminal.
Pull out the mains terminal.
 Reposition the mains terminal in the appliance from the
bottom to the top and secure the mains terminal by sliding it
under the locking hook.
 Lay the control wires below the wire guide.
Electrical connection for finished walls
!
Material losses
If you cut open the wrong knock-out in the appliance
cover by mistake, you must use a new appliance cover.
 Cut or break out the required entries in the back panel and
appliance cover cleanly (for positions, see chapter "Specifica-
tion/ Dimensions and connections"). If necessary, use a file.
 Route the power cable through the cable grommet. Connect
the power cable to the mains terminal.
Note
This type of connection changes the protection rating of
the appliance.
 Change the type plate. Cross out "IP 25" and mark
the box "IP 24". Please use a ballpoint pen to do this.
Large cross-section for electrical connection from below
If you use cables with a large cross-section, you can fit the cable
grommet after the appliance has been installed.
1.
3. 4.
2.
26�02�02�1124�
 Before installing the appliance, use a screwdriver to push out
the cable grommet.
 Slide the cable grommet over the power cable. For this, use
the installation aid. If the cross-section is >6mm², enlarge
the hole in the cable grommet.
 Push the cable grommet into the back panel.
Water installation on unfinished walls
26�02�02�0798
 Seal and screw in the twin connectors (not included in stand-
ard delivery).
D0000041724
2
3
1
3
1 Tee for cold water
2 Tee for domestic hot water
3 Cover
 Fit the water connections.
D0000043291
 Fit the strainer and the plastic profile washer in the tee for
the cold water inlet.

14 | DHE AU www.stiebel-eltron.com
INSTALLATION
Installation
!
Damage to the appliance and environment
The strainer must be fitted for the appliance to function.
 When replacing the appliance, check that the strain-
er is present.
 Screw the connection pipes from the appliance with flat gas-
kets to the tee.
 Open the shut-off valve in the cold water inlet line.
26�02�02�1102�
 Fit the lower part of the back panel. Ensure that it clicks into
place.
 Align the mounted appliance by loosening the fixing toggle,
aligning the power supply and back panel, and then re-tight-
ening the fixing toggle. If the back panel of the appliance is
not flush, the appliance can be secured at the bottom with an
additional screw.
Wall mounting bracket when replacing an appliance
When replacing an appliance, you can use an existing wall mount-
ing bracket of a StiebelEltron appliance (except for a DHF instan-
taneous water heater).
 Press the appliance over the threaded stud of the existing
wall mounting bracket. When doing so, push through the soft
seal in the back panel of the appliance. If necessary, use a
screwdriver.
DHF replacement
26�02�02�0815�
 Remove the DHF wall mounting bracket.
 Take the new wall mounting bracket and move the thread-
ed stud to the position marked with DHF (the stud has a
self-tapping thread).
 Rotate the wall mounting bracket 180° and mount it on the
wall. Use the existing drill holes.
Installation with offset tiles
110
20
2
1
D0000043278
1 Minimum contact area of the appliance
2 Maximum tile offset
 Adjust the wall clearance. Lock the back panel with the fixing
toggle by turning it 90° clockwise.
Pivoting appliance cover
The appliance cover can be turned for undersink installation.
electroniccomfort
electr onic co m f o r t
26�02�02�0553
 Remove the programming unit from the appliance cover by
pressing the locking hooks and taking out the programming
unit.
 Turn the appliance cover (not the appliance) and refit the
programming unit, ensuring that all locking hooks click into
place. When clicking the locking hooks into place, make sure
you press against the inner side of the appliance cover (shad-
ed area).
 Plug the set value transducer cable into the PCB (see chapter
"Commissioning/ Initial start-up").
 Hook the appliance cover back in at the bottom and pivot it
up onto the back panel.
 Ensure the all-round seal of the back panel is firmly seated
by pushing the appliance cover gently forwards and back.
 Secure the appliance cover.
Operation with preheated water
You can limit the maximum inlet temperature by installing a cen-
tral thermostatic valve.

ENGLISH
www.stiebel-eltron.com DHE AU| 15
INSTALLATION
Commissioning
11. Commissioning
WARNING Electrocution
Commissioning may only be carried out by a qualified
contractor in accordance with safety regulations.
11.1 Initial start-up
on
on
26�02�02�0554
 Open and close all connected draw-off valves several times,
until all air has been vented from the pipework and the
appliance.
 Carry out a tightness check.
 Activate the safety switch (AE 3) by firmly pressing the reset
button (the appliance is delivered with the safety switch
deactivated).
 Push the set value transducer cable plug onto the PCB.
 Fit the appliance cover and secure it with the screw.
 Switch the mains power ON.
 Check the function of the appliance.
 Remove the protective foil from the control fascia.
Appliance handover
 Explain the appliance function to users and familiarise them
with its operation.
 Make users aware of potential dangers, especially the risk of
scalding.
 Hand over these instructions.
11.2 Recommissioning
See chapter "Settings and displays / Following an interruption to
the water supply"
12. Service mode
26�02�02�1323�
 Open the appliance cover and hook it on the side of the back
panel.
26�02�02�0556�
1
1 Service button for activating and deactivating service mode
Key to symbols
Press once START
Press once END
Change settings/ scanning
In service mode you are able to call up and/ or change the set
temperature using the M key (60°C).

16 | DHE AU www.stiebel-eltron.com
INSTALLATION
Shutting down the system
Scanning the error menu
The error menu only appears if the appliance has a fault.
26�02�02�1313�
1 2 3 4
1 Electronic assembly symbol
 Replace the electronic assembly.
2 Safety circuit symbol
 Check the AE3 connection; replace the AE3 if required.
3 Outlet sensor symbol
 Check the outlet sensor connection; replace the outlet sensor
if required.
4 Motorised valve symbol
 Check the motorised valve connection; replace the motorised
valve if required.
Scanning the control menu
26�02�02�1312�
1 2 3 4
1 Inlet temperature symbol,
shows the current inlet temperature (shows 1.0°C if the sen-
sor is faulty).
2 Outlet temperature symbol,
shows the current outlet temperature (shows 65.0°C if the
sensor is faulty).
3 Flow rate symbol,
shows the current flow rate.
4 Power consumption symbol,
shows the current power consumption.
Scanning the appliance data menu
26�02�02�1314�
1 2 3 4
1 Service code symbol,
information for service engineers.
2 Symbol for power supply runtime,
accumulated runtime in days.
3 Heating hours symbol,
accumulated heating time in hours.
4 Maximum output symbol
The value shown may diverge by several kW from the rated
output if mains voltages other than 400V prevail.
Setting the anti-scalding protection
Use this anti-scalding protection in such places as nurseries and
hospitals. The temperature set here is also the upper limit for
the childproofing temperature setting (see chapter "Appliance
settings").
26�02�02�1301�
Setting range: 21 - 60°C
Recommended setting 43 °C
Note
The anti-scalding protection setting can only be modified
by a qualified contractor. Simultaneously pressing the M
+ i key will not change the setting.
13. Shutting down the system
 Isolate all poles of the appliance from the power supply.
 Drain the appliance (see chapter "Maintenance").
14. Troubleshooting
WARNING Electrocution
In order to check the appliance it must be connected to
the power supply.
Push-fit connections on the PCB
26�02�02�1343
1
5
6
7
2
34
1 Diagnostic traffic light (3 LEDs)
2 Flow sensor DFE
3 Motorised valve
4 High limit safety cut-out STB
5 Outlet sensor NTC
6 Set value transducer
7 Safety switch AE 3; plug-in connection secured with locking
tab.

ENGLISH
www.stiebel-eltron.com DHE AU| 17
INSTALLATION
Troubleshooting
Possible indications of diagnostic traffic light (LED)
Red Illuminates in the event of a fault
Yellow Illuminates during heating mode
Green Flashing: Appliance is supplied with mains power
Fault Cause Diagnostic traf-
fic light
Remedy
The appliance does
not heat up/ the set
temperature is not
reached.
There is no mains voltage. No LED illuminates Check the MCB/fuse in your fuse box/distribution panel.
The safety switch (AE 3) has
responded.
No LED illuminates Remove the cause of the fault.
Protect the heating system against overheating by opening a draw-off valve down-
stream of the appliance for one minute. Activate the safety switch by pressing the
pushbutton on the safety switch (see also chapter "Commissioning/ Initial start-
up").
The PCB is faulty. No LED illuminates Check the PCB and replace if necessary.
A phase has failed. Flashing green LED,
yellow LED on
Check the MCB/fuse in your fuse box/distribution panel.
The inlet temperature is
>55°C.
Flashing green LED,
red LED on
Limit the inlet temperature.
The flow sensor (DFE) is faulty
or not attached.
Flashing green LED,
yellow LED off
Check the connection of the flow sensor and replace if necessary.
The heating system is faulty. Flashing green LED,
yellow LED on
Check the heating system and replace if necessary.
The inlet sensor is faulty. Flashing green LED,
red LED on
Replace the PCB.
The outlet sensor is faulty. Flashing green LED,
red LED on
Check the connection of the outlet sensor and replace if necessary.
A fault in the safety PCB. Flashing green LED,
red LED only during
draw-off
Connect the connecting cable from the safety switch and check the safety switch.
A loose or faulty connecting
cable to the set value trans-
ducer.
Green LED flashes Connect the connecting cable from the set value transducer and check the connect-
ing cable.
The set value transducer is
faulty.
Green LED flashes Check the set value transducer and replace it if required.
Childproofing and/or tempera-
ture limiting is activated.
Green LED flashes Disable temperature limiting.
The display on the
appliance is complete-
ly off.
A loose connecting cable to the
set value transducer.
Green LED flashes Connect the connecting cable at the set value transducer and check the connecting
cable.
The programming PCB is faulty. Green LED flashes Check the programming unit and replace if necessary.
The flow rate is too
low.
The shower head/ aerators are
scaled up.
Descale or if necessary replace the shower head/ aerators.
The strainer is contaminated. Clean the strainer.
The set value cannot
be adjusted higher
than 43°C, nor can a
different set tempera-
ture be selected.
Dynamic anti-scalding protec-
tion is activated.
Green LED flashes The dynamic anti-scalding protection is deactivated again 2 minutes after draw-off.
Cold water flows brief-
ly during draw-off.
The flow rate
(<2 l/min) is too low.
The appliance restarts automatically when a flow rate of >2.5 l/min has been de-
tected.
The air sensor detects the
presence of air in the water and
briefly switches the heater off.
The appliance restarts after one minute.

18 | DHE AU www.stiebel-eltron.com
INSTALLATION
Maintenance
15. Maintenance
WARNING Electrocution
Before any work on the appliance, disconnect all poles
from the power supply.
Draining the appliance
You can drain the appliance for maintenance work.
CAUTION Scalding
Hot water may escape when draining the appliance.
 Close the shut-off valve in the cold water inlet line.
 Open all draw-off valves.
 Undo the water connections on the appliance.
 Store the dismantled appliance in a room free from the risk
of frost, as water residues remaining inside the appliance can
freeze and cause damage.
Cleaning the strainer
A strainer is located in the tee from the cold water inlet pipe. In
case of contamination, you can remove this strainer and clean it.
D0000043265
1
2
1 Strainer
2 Plastic profile washer
 Remove the plastic profile washer.
 Remove the strainer and clean the components.
 Fit the strainer and the plastic profile washer.
16. Specification
16.1 Dimensions and connections
473
478
100
414
44
105≤ 20225
140
30
35
35
114
368
b02
c01c06
493
D0000043287
b02 Entry electrical cables I
c01 Cold water inlet Male thread G 1/2 A
c06 DHW outlet Male thread G 1/2 A
Alternative connection options
165
50
44
30
35
72
325
338
47
b03
b02
b04
b04
b04
b04 b04
D0000043288
b02 Entry electrical cables I
b03 Entry electrical cables II
b04 Entry electrical cables III

ENGLISH
www.stiebel-eltron.com DHE AU| 19
INSTALLATION
Specication
16.2 Wiring diagram
3/PE ~ 380-415 V
L
2
III1
L2` L3`L1`
3/4
1342
III
UF
L L
85�02�02�0004�
13
4
2
1 Power PCB
2 Bare wire heating system
3 High limit safety cut-out
4 Safety switch
16.3 DHW output
DHW output is subject to the mains voltage, the appliance's con-
nected load and the cold water inlet temperature. The rated volt-
age and rated output can be found on the type plate (see chapter
"Troubleshooting").
Connected load in kW 38 °C DHW output in l/min.
Rated voltage Cold water inlet temperature
380 V 400 V 415 V 5°C 10°C 15°C 20°C
10.1 4.4 5.2 6.3 8.0
11.0 4.8 5.6 6.8 8.7
12.0 5.2 6.1 7.5 9.5
12.2 5.3 6.2 7.6 9.7
13.2 5.7 6.7 8.2 10.5
13.5 5.8 6.9 8.4 10.7
13.6 5.9 6.9 8.4 10.8
14.2 6.1 7.2 8.8 11.3
14.5 6.3 7.4 9.0 11.5
15.0 6.5 7.7 9.3 11.9
16.2 16.2 7.0 8.3 10.1 12.9
16.3 7.1 8.3 10.1 12.9
18.0 7.8 9.2 11.2 14.3
19.0 8.2 9.7 11.8 15.1
19.4 8.4 9.9 12.0 15.4
21.0 9.1 10.7 13.0 16.7
21.7 9.4 11.1 13.5 17.2
22.6 9.8 11.5 14.0 17.9
23.5 10.2 12.0 14.6 18.7
24.0 10.4 12.2 14.9 19.0
24.4 10.6 12.4 15.2 19.4
25.8 11.2 13.2 16.0 20.5
26.0 11.3 13.3 16.1 20.6
27.0 11.7 13.8 16.8 21.4
28.0 12.1 14.3 17.4 22.2
29.1 12.6 14.8 18.1 23.1
Connected load in kW 50 °C DHW output in l/min.
Rated voltage Cold water inlet temperature
380 V 400 V 415 V 5°C 10°C 15°C 20°C
10.1 3.2 3.6 4.1 4.8
11.0 3.5 3.9 4.5 5.2
12.0 3.8 4.3 4.9 5.7
12.2 3.9 4.4 5.0 5.8
13.2 4.2 4.7 5.4 6.3
13.5 4.3 4.8 5.5 6.4
13.6 4.3 4.9 5.6 6.5
14.2 4.5 5.1 5.8 6.8
14.5 4.6 5.2 5.9 6.9
15.0 4.8 5.4 6.1 7.1
16.2 16.2 5.1 5.8 6.6 7.7
16.3 5.2 5.8 6.7 7.8
18.0 5.7 6.4 7.3 8.6
19.0 6.0 6.8 7.8 9.0
19.4 6.2 6.9 7.9 9.2
21.0 6.7 7.5 8.6 10.0
21.7 6.9 7.8 8.9 10.3
22.6 7.2 8.1 9.2 10.8
23.5 7.5 8.4 9.6 11.2
24.0 7.6 8.6 9.8 11.4
24.4 7.7 8.7 10.0 11.6
25.8 8.2 9.2 10.5 12.3
26.0 8.3 9.3 10.6 12.4
27.0 8.6 9.6 11.0 12.9
28.0 8.9 10.0 11.4 13.3
29.1 9.2 10.4 11.9 13.9
16.4 Application areas / conversion table
For the specific electrical resistance and specific electrical
conductivity, see "Data table".
Standard specifi-
cation
at 15 °C 20°C 25°C
Spec.
resist-
ance
ρ ≥
Spec. conductiv-
ity σ≤
Spec.
resist-
ance
ρ ≥
Spec. conductiv-
ity σ≤
Spec.
resist-
ance
ρ ≥
Spec. conductiv-
ity σ≤
Ωcm mS/m μS/cm Ωcm mS/m μS/cm Ωcm mS/m μS/cm
900 111 1111 800 125 1250 735 136 1361
1000 100 1000 890 112 1124 815 123 1227
1100 91 909 970 103 1031 895 112 1117
1200 83 833 1070 93 935 985 102 1015
1300 77 769 1175 85 851 1072 93 933
16.5 Pressure drop
Taps/valves
Pressure drop at taps at flow rate of 10 l/min
Mono lever mixer tap, approx. MPa 0.04 - 0.08
Thermostatic valve, approx. MPa 0.03 - 0.05
Hand shower, approx. MPa 0.03 - 0.15
Sizing the pipework
In case of faults, loads up to 80°C at a pressure of 1.2MPa can
occur temporarily in the installation.

20 | DHE AU www.stiebel-eltron.com
INSTALLATION
Specication
16.6 Fault conditions
In case of faults, loads up to 80°C at a pressure of 1.2MPa can
occur temporarily in the installation.
16.7 Data table
DHE 18 AU DHE 27 AU
233988 233989
Electrical data
Rated voltage V380 400 415 380 400 415
Rated output kW 16.2 18 19.4 24.4 27 29.1
Rated current A24.7 26 27 37.1 39 40.5
Fuse/MCB rating A25 25 32 40 40 40
Phases 3/PE 3/PE
Frequency Hz 50/60 50/60 50/- 50/- 50/- 50/-
Max. mains impedance at 50Hz Ω 0.3 0.285 0.274 0.2 0.19 0.183
Max. mains impedance at 60Hz Ω0.36 0.342
Specific resistance ρ15 ≥ (at ϑcold ≤55°C) Ω cm 900 900 900 900 900 900
Specific conductivity σ15 ≤ (at ϑcold ≤55°C) μS/cm 1111 1111 1111 1111 1111 1111
Connections
Water connection G 1/2 A G 1/2 A
Application limits
Max. permissible pressure MPa 1 1
Max. inlet temperature for reheating °C 55 55
Values
Max. permissible inlet temperature °C 65 65
On l/min > 2.5 > 2.5
Flow rate for pressure drop l/min 5.2 7.7
Pressure drop at flow rate MPa 0.04 0.1
DHW delivery l/min 9.2 13.8
Δϑon delivery K28 28
Hydraulic data
Nominal capacity l0.4 0.4
Versions
Temperature setting °C 20-60 20-60
Safety category 1 1
Insulating block Plastic Plastic
Heating system Bare wire Bare wire
Cover and back panel Plastic Plastic
Colour white white
IP rating IP25 IP25
Dimensions
Height mm 478 478
Width mm 225 225
Depth mm 105 105
Weights
Weight kg 4.5 4.5