STIEBEL ELTRON DHX 3.5-1 Trend Instruction Manual

OPERATION AND INSTALLATION
FUNCIONAMIENTO E INSTALACIÓN
Electronically Controlled Electric Tankless Water Heaters
Calentadores de Agua Electrónicos sin Tanque
» DHX 3.5-1 Trend
» DHX 6-2 Trend
» DHX 8-2 Trend
»DHX10-2Trend
»DHX12-2Trend
»DHX15-2Trend
»DHX12-2Plus
»DHX15-2Plus
Certified to ANSI/UL Std. 499
Conforms to CAN/CSA Std. C22.2 No. 64
Certificación ANSI/UL Std. 499
Conforme a CAN/CSA Std. C22.2 No.64
Tested and certified by WQA to NSF/ANSI372
for lead free compliance.
Probado y certificado por WQA NSF/ANSI 372 para
el cumplimiento de las regulaciones sin plomo.
i

2| DHX Trend & DHX Plus www.stiebel-eltron-usa.com
CONTENTS
QUICK START GUIDE
SPECIAL INFORMATION
OPERATION
1. General information ___________________________________________ 5
1.1 Safety instructions__________________________________________________ 5
1.2 Other symbols in this documentation __________________________ 5
1.3 Units of measurement _____________________________________________ 5
2. Safety____________________________________________________________ 5
2.1 Intended use_________________________________________________________ 5
2.2 General safety instructions _______________________________________ 5
2.3 Test symbols _________________________________________________________ 6
2.4 Licenses / certificates ______________________________________________ 6
3. Register your product _________________________________________ 6
4. Water heater description______________________________________ 7
5. Settings and displays __________________________________________ 7
5.1 DHX Trend user interface _________________________________________ 7
5.2 DHX Plus user interface ___________________________________________ 8
5.3 Using the display menus __________________________________________ 8
5.4 DHX Trend display __________________________________________________ 8
5.5 DHX Plus display ____________________________________________________ 9
5.6 Recommended settings __________________________________________12
6. Cleaning, care and maintenance ____________________________12
7. Troubleshooting _______________________________________________13
INSTALLATION
8. Safety___________________________________________________________13
8.1 General safety instructions ______________________________________13
8.2 Instructions, standards and regulations ______________________13
9. Water heater description_____________________________________13
9.1 Standard delivery__________________________________________________13
10. Preparation ____________________________________________________14
10.1 Installation site_____________________________________________________14
10.2 Minimum clearances______________________________________________14
11. Installation_____________________________________________________14
11.1 Standard wall-mounted installation___________________________14
11.2 Water connections_________________________________________________15
11.3 Aerator installation at connected faucet ______________________16
11.4 Electrical connection______________________________________________16
11.5 Electrical connection with short power cable _______________17
11.6 Wiring block ________________________________________________________17
12. Commissioning ________________________________________________ 17
12.1 Internal anti-scalding protection via jumper slot ___________17
12.2 Initial start-up______________________________________________________17
12.3 Operation with preheated water _______________________________18
12.4 Recommissioning__________________________________________________18
13. Water heater shutdown ______________________________________18
14. Service information ___________________________________________ 19
15. Maintenance ___________________________________________________ 19
15.1 Draining the water heater _______________________________________19
15.2 Cleaning the filter screen ________________________________________19
16. Troubleshooting _______________________________________________20
17. Specification ___________________________________________________21
17.1 Dimensions and connections____________________________________21
17.2 Wiring diagrams ___________________________________________________21
17.3 Hot water output___________________________________________________22
17.4 Application areas/conversion table ____________________________22
17.5 Fault conditions ____________________________________________________22
17.6 Data table ___________________________________________________________23
18. Spare parts ____________________________________________________24
19. Warranty _______________________________________________________25

QUICK START GUIDE
ENGLISH
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QUICK START GUIDE
Before turning on power to the water heater, you MUST flush all air out of the
system, then engage the AE3 safety switch. The unit will NOT operate until
the AE3 safety switch has been engaged.
1 Mount the unit to the wall (see section 11.1, “Standard wall-mounted installation”, pg. 14).
2 Hook up water connections (see section 11.2, “Water connections”, pg. 15).
3 Hook up electrical connections, but keep circuit breaker off. (See section 11.4, “Electrical connec-
tion”, pg. 16)
PLQ
12
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4 Open and close all connected draw-off valves at least 5 times, for at least 3 minutes total,
until all air has been purged from the pipework and the water heater.
5 Ensure there are no water leaks from any plumbing connections.
D0000094561-b
6 Engage the AE3 safety switch by firmly pressing the white reset button until it clicks and fully
locks in place (the water heater is delivered with the safety switch disengaged).
7 Turn on power to the water heater at the circuit breaker in the breaker panel.

SPECIAL INFORMATION
4| DHX Trend & DHX Plus www.stiebel-eltron-usa.com
SPECIAL INFORMATION
- Read this entire manual. Failure to follow all the
guides, instructions and rules could cause personal
injury or property damage. Improper installation, ad-
justment, alteration, service and use of this unit can
result in serious injury.
- This unit must be installed by a licensed electrician
and plumber. The installation must comply with all
national, state and local plumbing and electric codes.
Proper installation is the responsibility of the install-
er. Failure to comply with the installation and operat-
ing instructions or improper use voids the warranty.
- Save these instructions for future reference. The
installer should leave these instructions with the
consumer.
- If you have any questions regarding the installation,
use or operation of this water heater, or if you need
any additional installation manuals, please call our
technical service line at 800.582.8423 (USA and Can-
ada only). If you are calling from outside the USA or
Canada, please call USA 413.247.3380 and we will
refer you to a qualified Stiebel Eltron service repre-
sentative in your area.
- The water heater is suitable for supplying a shower in
many climates (shower operation). If the water heater
is also or exclusively used for shower operation, the
qualified contractor must adjust the temperature set-
ting range to 122°F (50°C) or less using the internal
anti-scalding protection on the water heater. When
using preheated water, it must be ensured that the
inlet temperature does not exceed 131°F (55 °C).
- Ensure the water heater can be separated from the
power supply by a circuit breaker that disconnects all
poles with at least 1/8˝ (3mm) contact separation.
- The specified voltage must match the power supply.
See the type plate on the right-hand side of the water
heater for full information.
- CAUTION: DO NOT INSTALL IN A BATH ENCLOSURE OR
SHOWER STALL.
DO NOT CONNECT TO A SALT-REGENERATED WATER
SOFTENER OR A SALT-WATER WATER SUPPLY.
FOR USE ON AN INDIVIDUAL BRANCH CIRCUIT ONLY.
CAUTION: CONNECT ONLY TO A CIRCUIT PROTECTED
BY A CLASS A GROUND FAULT INTERRUPTER
USE BONDING CONDUCTOR IN ACCORDANCE WITH
THE CANADIAN ELECTRICAL CODE, PART I
- The water heater must be properly grounded. See
section 17.2, “Wiring diagrams,” pg. 21.
- The water heater must be permanently connected to
fixed wiring. For use on an individual branch circuit
only. See section 17.2, “Wiring diagrams,” pg. 21.
- Secure the water heater as described in chapter 11,
“Installation”, pg. 14.
- Observe the minimum permissible water supply
pressure of 26.1 psi (1.8 bar). See section 17.6, “Data
table,” pg. 23.
- Observe the maximum permissible water supply
pressure of 145 psi (10 bar). See section 17.6, “Data
table,” pg. 23.
- Drain the water heater as described in section 15.1,
“Draining the water heater”, pg. 19.

OPERATION
General information
ENGLISH
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OPERATION
1. General information
The chapters "Special information" and "Operation" are intended for
both users and qualified contractors.
The chapter "Installation" is intended for qualified contractors.
Note
Read these instructions carefully before using the water
heater 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.
f Steps to prevent the risk are listed.
1.1.2 Symbols, type of risk
Symbol Type of risk
Injury
Electrocution
Burns
(burns, scalding)
1.1.3 Keywords
KEYWORD Meaning
DANGER Failure to observe this information will result in serious in-
jury 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-serious
or minor injury.
1.2 Other symbols in this documentation
Note
General information is identified by the adjacent symbol.
f Read these texts carefully.
Symbol Meaning
Material losses
(water heater damage, material losses, and installation site
damage)
f This symbol indicates that you have to do something. The ac-
tion you need to take is described step by step.
1.3 Units of measurement
Note
All measurements are given in inches (millimeters) unless
otherwise stated.
2. Safety
2.1 Intended use
This water heater is suitable for heating domestic hot water or for
reheating preheated water. The water heater can supply one or
more draw-off points.
Water will not be reheated if the maximum inlet temperature for
reheating is exceeded.
The water heater is intended for domestic use. It can be used safely
by untrained persons. The water heater can also be used in non-do-
mestic environments, e.g. in small businesses, as long as it is used
in the same way.
Any other use beyond that described shall be deemed inappropriate.
Observation of these instructions and of the instructions for any
accessories used is also part of the correct use of this water heater.
2.2 General safety instructions
DANGER: Burns
Water temperatures over 125 °F (52°C) can cause severe
burns instantly or death from scalding. A hot water scald-
ing potential exists if the thermostat on the water heater
is set too high. Households with small children, disabled
or elderly persons may require that the thermostat be set
at 113°F (45 °C) or lower to prevent possible injury from
hot water.
CAUTION: Burns
If operating with preheated water, e.g.from a solar ther-
mal system, the DHW temperature may vary from the
selected set temperature.
!
!

OPERATION
Register your product
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CAUTION: Burns
During operation, the tap can reach temperatures up to
149°F (65°C).
There is a risk of scalding at outlet temperatures in excess
of 110°F (43 °C).
!
DANGER: Injury
Please read and follow these instructions. Failure to follow
these instructions could result in serious personal injury
or death.
!
CAUTION: DO NOT INSTALL IN A BATH ENCLOSURE
OR SHOWER STALL. DO NOT CONNECT TO A
SALT-REGENERATED WATER SOFTENER OR A WATER
SUPPLY OF SALT WATER.
FOR USE ON AN INDIVIDUAL BRANCH CIRCUIT ONLY.
CAUTION: CONNECT ONLY TO A CIRCUIT PROTECTED BY A
CLASS A GROUND FAULT INTERRUPTER
USE BONDING CONDUCTOR IN ACCORDANCE WITH THE CA-
NADIAN ELECTRICAL CODE, PART I
DANGER: Electrocution
Before proceeding with any installation, adjustment,
alteration, or service of this appliance, all circuit break-
ers and disconnect switches servicing the appliance
must be turned off. Failure to do so could result in seri-
ous personal injury or death.
DANGER: Electrocution
Never remove the water heater’s cover unless the elec-
tricity servicing the water heater is turned off. Failure to
do so could result in personal injury or death.
WARNING Electrocution
The connection to the power supply is only permissible as
a permanent connection in conjunction with a ¾˝Romex
clamp. Ensure the water heater can be separated from
the power supply by an isolator that disconnects all poles
with at least 1/8˝(3mm) contact separation.
!
WARNING: Injury
Where children or persons with limited physical, sensory
or mental capabilities are to be allowed to control this
water heater, ensure that this will only happen under su-
pervision or after appropriate instructions by a person re-
sponsible for their safety. Children should be supervised to
ensure that they never play with the water heater.
!
DAMAGE TO THE WATER HEATER AND THE ENVIRON-
MENT:
The water heater must be installed by a licensed electrician
and plumber. The installation must comply with all nation-
al, state and local plumbing and electric codes.
Service of the water heater must be performed by qualified
service technicians.
!
DAMAGE TO THE WATER HEATER AND THE ENVIRON-
MENT:
Supply this appliance only from a grounded system. A
green terminal (or a wire connector marked “G”, “GR”,
“GROUND”, OR “GROUNDING”) is provided for wiring the
appliance. To reduce the risk of electric shock, connect
this terminal or connector to the grounding terminal of the
electric service or supply panel with a continuous copper
wire in accordance with the electrical installation code.
Where children or persons with limited physical, sensory or mental
abilities are allowed to use this water heater, we recommend a
permanent temperature limit. The following limitation options are
available:
- All DHX models - qualified contractor adjustable: “Internal
anti-scalding protection”
- DHX Plus only - user adjustable: Temperature limit
(childproofing)
!
Material losses
The user should protect the water heater against frost.
2.3 Test symbols
See type plate on the water heater.
2.4 Licenses / certificates
- UL (USA) Std. 499
- CSA (Canada) Std. C22.2 No. 64
3. Register your product
You must register this product within 90 days of pur-
chase on our web site in order to activate the standard
warranty. Go to our web site at
www.stiebel-eltron-usa.com and click on “Register
Your Product.”
Before beginning the registration process, we suggest that you
gather the necessary information which will be as follows:
Type, Example: DHX 15-2 Plus (from the label that is on the unit)
Number listed after “Nr.”
Place of Purchase
Purchase Date
First & Last Name
Email address
Physical Address
Phone Number
Installation Date
If you have any questions concerning the registration pro-
cess or warranty, please contact Stiebel Eltron USA directly at
800.582.8423.

OPERATION
Water heater description
ENGLISH
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4. Water heater description
The water heater switches on automatically as soon as a hot water
valve at a tap or other draw-off point is opened. DHX heats water as
it flows through the unit. When the tap is closed, the water heater
switches off automatically.
From the activation flow rate, the electronic control unit regulates
the correct heating output using only the minimum amount of power
necessary, subject to the temperature selected and the current in-
coming cold water temperature.
DHX Trend and DHX Plus are electronically controlled tankless water
heaters, and maintain a consistent outlet temperature. This is irre-
spective of the inlet water temperature, up to the maximum output
of the water heater.
DHX Plus models feature Advance Flow Control™, a technology pat-
ented by Stiebel Eltron in Germany (patent no. DE 3805441 C2). When
the maximum output of a DHX Plus model is met, rather than deviate
from the setpoint temperature and deliver cooler water, DHX Plus
models use an electronically-controlled motorized valve to slightly
reduce the flow of water only as much as is necessary to maintain
the user-selected temperature. When the demand can again be fully
met, the motorized valve returns to the fully open position, allowing
the full flow rate. This ensures uninterrupted comfort, and hot water
delivered at the desired temperature at all times.
If the water heater is operated with preheated water, and the inlet
temperature exceeds the selected set temperature, the inlet tem-
perature will be displayed on the second row of the screen (DHX
Plus models only) and will flash. The water is not heated further.
DHX models are equipped with functions to permanently limit the
temperature (childproofing).
DHX Plus models feature a backlit display that switches on auto-
matically as soon as water flows through the unit, or if a change is
made at the user interface. The backlight switches off automatically
if no changes are made for 30seconds, or 5seconds after hot water
stops being drawn.
DHX Plus models allow the user to save different preset tempera-
tures and apply them quickly.
DHX Plus models also offer a more in-depth 2-line display with
enhanced functions. The DHX Trend has a single-line display and a
more basic user feature set.
Domestic Hot Water (DHW) temperature
The DHW outlet temperature can be variably adjusted from 68–140°F
(20–60°C). The selected temperature is displayed.
Heating system
The Direct Coil™heating system is comprised of a pressure-tested,
glass-reinforced polyamide heating chamber with a nichrome wire
direct heating coil. It is suitable for hard and soft water areas and
is largely insusceptible to scale build-up. The Direct Coil™heating
system ensures rapid and efficient DHW production.
Note
The water heater is equipped with an air detector that
largely prevents damage to the heating system. If, during
operation, air is drawn into the water heater, the water
heater shuts down the heating output for one minute to
protect the heating system.
5. Settings and displays
5.1 DHX Trend user interface
2
3
1
1 Display
2 Operating LED (flashes when output limit is reached)
3 Control knob
5.1.1 DHX Trend display overview
12
1 Digit display
2 Temperature unit indicator

OPERATION
Settings and displays
8| DHX Trend & DHX Plus www.stiebel-eltron-usa.com
5.2 DHX Plus user interface
D0000073619
2
3
1
8
5
6
7
4
1 Control knob
2 Operating LED (flashes when output limit is reached)
3 Temperature memory keys
4 Backlit display
5 Main display | info display | parameter display
6 Segment display [10–100%]
7 Second row of screen
8 “i” button to retrieve information and select menus
5.2.1 DHX Plus display overview
1
2
3
4
678
9
10
1112
13
14
5
1 Primary digit display
2 Power capacity status
3 Display-lock indicator
4 Error code symbol
5 Secondary digit display
6 Tmax indicator
7 Savings statistics indicator
8 x1000 secondary display value
9 Gallons secondary display unit
10 kWh secondary display unit
11 Liters & liters per minute secondary display unit
12 Gallons per minute secondary display unit
13 Temperature unit for secondary display
14 Temperature unit for primary display
5.3 Using the display menus
The DHX Trend and DHX Plus feature an interactive display that allow
for user customization to increase the level of comfort for the user.
The menu structure is designed in an intuitive, linear way to make
it as navigable as possible.
5.3.1 DHX Trend user input
User input
Control knob (turn knob to change settings)
5.3.2 DHX Plus user input
User input
Information button (pressing or holding this
button performs different functions)
Preset 1 button (pressing or holding this but-
ton performs different functions)
Preset 2 button (pressing or holding this but-
ton performs different functions)
Control knob (turn knob to change settings)
5.4 DHX Trend display
The DHX Trend display features a temperature readout capable of
showing the currently selected temperature in either Fahrenheit
or Celsius.
For the name of each display element on the DHX Trend, consult
section 5.1.1, “DHX Trend display overview”, pg. 7.

OPERATION
Settings and displays
ENGLISH
www.stiebel-eltron-usa.com DHX Trend & DHX Plus | 9
5.4.1 Base display
The base display shows the current temperature setpoint in your
preferred temperature unit.
Changing the setpoint temperature
Temperature settings
Range Increment Range Increment
68–140°F 1°F 20–60°C. 1 °C
The setpoint temperature can be set between 68 °F (20°C) and 140°F
(60 °C).
The setpoint can be increased by turning the control knob clockwise,
and decreased by turning it counter-clockwise. The water heater
can be deactivated while still powered by turning the control knob
counter-clockwise, past the 68 °F (20 °C) setting.
5.4.2 Temperature units parameter setting
The DHX Trend is capable of displaying temperature in either Fahr-
enheit or Celsius.
f To change between Fahrenheit (default) and Celsius, first rotate
the control knob to the left until the display reads “Off.”
f Once “Off” is showing on the display, turn the control knob 5
full 360° rotations to the left. This will open the temperature
parameter menu:
Turn full 360°
5 times to the left
Turn full 360°
5
t
i
mes to the le
f
t
The current unit will be shown and the display will be flashing to
indicate that the value can be changed. Rotate the control knob to
change the value between Fahrenheit and Celsius.
5.4.3 Returning to the base display
The display will revert to the base display after a 30-second period
with no user input.
5.5 DHX Plus display
The DHX Plus features a primary and secondary display area al-
lowing for multiple parameters or information to be displayed. The
DHX Plus is capable of displaying the current flow rate of the water
passing through the water heater, as well as calculating the accu-
mulated cost savings of having a tankless water heater compared
to a tank-type water heater.
For the name of each display element on the DHX Plus, consult
section 5.2.1, “DHX Plus display overview”, pg. 8.
5.5.1 Base display
The DHX Plus base display shows the current setpoint temperature
in your preferred temperature unit in the top half of the display.
The bar below the temperature shows the current fraction of total
capacity that the water heater is running at. As the hot water demand
fluctuates, the power capacity status will change to show between
0 and 10 segments. The display below shows that the water heater
is operating at 30% of full capacity.
The bottom half of the display shows the current flow rate through
the unit in either gallons per minute (gpm) or liters per minute (l/
min).
All other menus will revert back to the base display either after a
15-second period of time without user input, or after a 5-second
hold of the Information button.
Changing the setpoint temperature
Temperature settings
Range Increment Range Increment
68–140°F 1°F 20–60°C 0.5°C
The setpoint temperature can be set between 68 °F (20°C) and 140°F
(60 °C).
The setpoint can be increased by turning the control knob clockwise,
and decreased by turning it counter-clockwise. The water heater
can be deactivated while still powered by turning the control knob
counter-clockwise, past the 68 °F (20 °C) setting.
5.5.2 Information menu
The information menu structure displays additional information for
the user. The information menu is accessed by pressing the Infor-
mation button while at the base display.
Accumulated cost savings display
If the Information button is pressed while the display is showing
the base display, the display will advance to the accumulated cost
savings display.
The accumulated cost savings display will display the current set-
point temperature in the top half of the display, and the bottom half
of the display will alternate between “Cur” and the accumulated
savings of the water heater.

OPERATION
Settings and displays
10 | DHX Trend & DHX Plus www.stiebel-eltron-usa.com
The accumulated cost savings updates daily, and shows the esti-
mated savings for the user compared to an installation where a
50-gallon tank-type water heater was used.
Note
The energy saving values are calculated starting from the
last reset.
This savings estimate is based on the users electricity cost. For the
most accurate estimate, the electricity cost per kWh should be set in
the electricity cost parameter setting menu. For information on how
to do this, see section “Electricity cost parameter setting”, pg. 10.
Pressing the Information button will advance back to the base dis-
play. The display will also revert back to the base display if no user
input is detected for 10 seconds.
5.5.3 Parameters menu
The parameter menu allows multiple settings on the DHX Plus to
be altered. The parameter menu can be accessed by holding the
Information button for 5 seconds.
Tmax parameter setting
The first parameter menu sets the value for Tmax. The value of Tmax
acts as a high temperature limiter. If the Tmax value is set, the set-
point of the water heater cannot be set above the Tmax value. This
feature is useful in scenarios where scalding from hot water is a
real possibility.
At the Tmax setting menu, the temperature value will flash, indicating
that the value can be changed by rotating the control knob. The Tmax
value can be increased by turning the control knob clockwise, and
decreased by turning it counter-clockwise. The Tmax value can be
deactivated by turning the control knob counter-clockwise, past the
68 °F (20 °C) setting. The display will read “Off” if Tmax is inactive.
If the Tmax symbol is visible at the base display, then the Tmax function
is active and limiting the maximum allowable temperature.
Pressing the Information button once while at this menu will move
the display onto the temperature units parameter setting.
Temperature units parameter setting
The DHX Plus is capable of displaying temperature in either degrees
Fahrenheit or degrees Celsius.
The current unit will be shown and the secondary display value will
be flashing to indicate that the value can be changed. Rotate the
control knob to change the value between degrees Fahrenheit and
degrees Celsius.
Pressing the Information button once while at this menu will move
the display onto the volume units parameter setting.
Volume units parameter setting
The DHX Plus is capable of displaying volume or volume flow in
either gallons per minute (gpm) or liters per minute (l/min).
The current volume unit will be displayed and the value will be
flashing to indicate that it can be changed. Rotate the control knob to
change the value between gallons per minute and liters per minute.
Pressing the Information button once while at this menu will advance
the display to the electricity cost parameter setting.
Electricity cost parameter setting
The DHX Plus has a built-in feature where it calculates the energy
savings of the unit when compared to the average energy use of a
tank-type water heater. In order for this feature to be accurate, the
cost per kWh of electricity must be programmed into the software.

OPERATION
Settings and displays
ENGLISH
www.stiebel-eltron-usa.com DHX Trend & DHX Plus | 11
The secondary display will be flashing to indicate that the value can
be changed by rotating the control knob. Consult your electricity bill
to determine the cost of electricity per kWh.
Pressing the Information button once while at this menu will advance
the display to the display-lock parameter setting.
Display-lock parameter setting
The display can be locked to prevent easy alteration of the tempera-
ture setpoint. This menu will flash, indicating that the value can be
changed by rotating the control knob. While “Off” is displayed, the
lock is not active. The lock is active when the display reads “On”.
If the display-lock parameter is set to “On” and the user either holds
the Information button for 5 seconds or lets the display time out for
15 seconds, the display-lock will become active.
With the display-lock active, a lock will appear on the base display,
and no parameters can be changed. In order to disable the lock, hold
the Information button for 12 seconds. The lock will then disappear
and all parameters can be changed again.
Pressing the Information button once while at the display-lock pa-
rameter setting menu will move the display onto the factory setting
reset parameter menu.
Factory setting reset parameter
The temperature setpoint, preset values, temperature, & volume
units can all be reset to their factory settings.
The display will be flashing to indicate that the value can be changed
by rotating the control knob. To reset, first press and hold both
buttons 1 and 2 for 5 seconds, “On” then appears. Then push infor-
mation button for 5 seconds to reset.
Pressing the Information button once will advance the display to the
accumulated savings reset parameter menu.
Accumulated savings reset parameter
Much like the factory setting reset parameter, the calculated accu-
mulated savings value can be reset to zero.
The display will be flashing to indicate that the value can be changed
by rotating the control knob. To reset, first press and hold both
buttons 1 and 2 for 5 seconds, “On” then appears. Then push infor-
mation button for 5 seconds to reset.
Pressing the Information button once will advance the display to the
display backlight time-out parameter.
Display backlight time-out parameter
The backlight of the display can be set to be always on, or set to an
automatic mode that deactivates when no user input is detected for
30 seconds.
The entire display and backlight will be flashing to indicate that the
value can be changed by rotating the control knob. When the value is
set to “On”, the backlight will always be on. When the value is set to
“Auto”, it will automatically deactivate after 30 seconds of inactivity.
Pressing the Information button once while at this menu will advance
the display to the backlight display brightness parameter menu.
Backlight display brightness parameter
The brightness of the display backlight can be adjusted to two differ-
ent parameters. A high and low setting allows for user customization
depending on the light conditions in the installation location.
The power capacity status bar indicates the brightness setting. A
full capacity bar indicates that the brightness is at the high setting.
Two capacity bars indicate that the brightness is at the low setting.

OPERATION
Cleaning, care and maintenance
12 | DHX Trend & DHX Plus www.stiebel-eltron-usa.com
Pressing the Information button once while at this menu will advance
the display back to the Tmax parameter setting page, labeled “P1”.
5.5.4 Temperature preset options
DHX Plus models feature two temperature preset settings to allow
for quickly accessible setpoints. Button 1 and Button 2 are capable
of each storing an independent setpoint value.
Changing setpoint to preset values
While the display is at the base display, the user can press either But-
ton 1 or Button 2 to change the setpoint to the buttons stored value.
Press
Pr
es
s
When the button is pressed, the setpoint value will change to what-
ever value was stored up to that point.
Changing the preset values
The preset values can be changed from the default setpoint values.
Hold 3
seconds
Hol
d
3
s
econds
To change the value of either preset 1 or preset 2, first rotate the
control knob to the temperature that you want to set as the preset
value. Then hold the preset button for 3 seconds. The display will
flash to indicate that the preset has been changed successfully.
5.5.5 DHX Plus error menu
If the DHX Plus encounters an error, a wrench will illuminate in the
bottom left of the display.
Hold 5
seconds
H
old
5
s
econ
d
s
While the wrench is showing, press and hold the Information button
for five seconds to advance the display to the error display page.
Consult section 16, “Troubleshooting”, pg. 20, for information on
how to interpret the reported error code.
5.5.6 Returning to the base display
While navigating the display and on any menu other than the base
display, holding the Information button for 5 seconds will return the
display to the base display. Additionally, the display will revert from
a parameter menu to the base display after a 15-second period with
no user input, or from an information menu to the base display after
a 10-second period with no user input.
5.6 Recommended settings
Your electric tankless water heater offers maximum precision and
convenience for DHW production. Should you nonetheless operate
the water heater with a thermostatic valve, we recommend that you:
f Adjust the set temperature on the water heater to over 122 °F
(50°C). Then set the required set temperature on the thermo-
static valve.
Saving energy
The following recommended settings will result in the lowest energy
consumption:
- 100 °F (38 °C) for hand washbasins, showers, bath
- 131°F (55°C) for kitchen sinks
Internal anti-scalding protection (qualified contractors)
If required, the qualified contractor can set a permanent temperature
limit, for example in nurseries, hospitals,etc.
Recommended setting for operation with a thermostatic valve
and water preheated by solar energy
f Set the temperature at the water heater to the maximum
temperature.
Following an interruption to the water supply
!
Material losses
To ensure that the Direct Coil™heating system is not dam-
aged following an interruption to the water supply, the
water heater must be restarted by taking the following
steps:
f Disconnect the water heater from the power supply by
turning off the connected circuit breaker.
f Open and close all connected draw-off valves at least 5
times, for at least 3 minutes total, until all air has been
purged from the pipework and the water heater.
f Switch the power back at the circuit breaker back ON.
6. Cleaning, care and maintenance
f Never use abrasive or corrosive cleaning agents. A damp cloth
is sufficient for cleaning the water heater.
f Check the taps regularly. Limescale deposits at the tap outlets
can be removed using commercially available descaling agents.

INSTALLATION
Troubleshooting
ENGLISH
www.stiebel-eltron-usa.com DHX Trend & DHX Plus | 13
7. Troubleshooting
Problem Cause Solution
The water heater will not
start despite the DHW
valve being fully open
There is no power Check to ensure circuit
breaker in breaker panel
hasn’t tripped. Reset if
necessary
The white AE3 safety
switch has not been
engaged during initial
startup. Activate if neces-
sary (See section 12.2.1,
“Initial AE3 safety switch
activation,” pg. 18). If
the AE3 switch has tripped
after initial installation,
contact a qualified con-
tractor to fix the cause
The aerator in the tap or
the shower head is scaled
up or dirty
Clean and/or descale the
aerator or shower head
The water supply has
been interrupted
Vent the water heater and
the cold water inlet line
When hot water is being
drawn off, cold water
flows for a short period
The air detector detects
air in the water. It switch-
es off the heating output
briefly
The water heater restarts
automatically after 1min-
ute
The required temperature
cannot be set
Internal anti-scalding pro-
tection is active
The internal anti-scalding
protection can only be
adjusted by qualified con-
tractors
If you cannot solve the problem, contact your qualified contractor.
To facilitate and speed up your inquiry, please provide the serial
number from the type plate (000000-0000-000000). For live technical
assistance, please contact us at 800.582.8423. Alternatively, you may
email us at [e-mail]
Nr.: 000000-0000-00000
D0000094552-b
INSTALLATION
8. Safety
Only a qualified contractor should carry out installation, commis-
sioning, maintenance and repair of the water heater.
8.1 General safety instructions
We guarantee trouble-free function and operational reliability only
if original accessories and spare parts intended for the water heater
are used.
!
Material losses
Observe the maximum inlet temperature. Higher tempera-
tures may damage the water heater. You can limit the max-
imum inlet temperature by installing a central thermostatic
valve.
WARNING Electrocution
This water heater contains capacitors which are discharged
when disconnected from the power supply. The capacitor
discharge voltage may briefly exceed60VDC.
8.2 Instructions, standards and regulations
Note
Observe all applicable national and regional regulations
and instructions.
- The electrical resistivity of the water must not fall below that
stated on the type plate. In a linked water network, factor in
the lowest electrical resistivity of the water. Your water supply
utility will advise you of the electrical resistivity or conductivity
of the water in your area.
9. Water heater description
9.1 Standard delivery
The following are delivered with the water heater:
- Filter screen, factory installed in cold water inlet
- Jumper for anti-scalding protection, attached
- Jumper, spare, attached
- 2 x mounting screws
- 2 x wall anchors
- 0.5 gpm (1.9 l/min) flow-reducer/aerator [DHX 3.5-1 Trend
only]. See section 11.3, “Aerator installation at connected fau-
cet,” pg. 16, for more information.
- 1.0 gpm (3.8 l/min) flow-reducer/aerator [DHX 6-2 Trend only].
See section 11.3, “Aerator installation at connected faucet,” pg.
16, for more information.

INSTALLATION
Preparation
14 | DHX Trend & DHX Plus www.stiebel-eltron-usa.com
10. Preparation
10.1 Installation site
!
Material losses
Install the water heater in a room that is free from the risk
of frost.
f Install DHX in a frost free area. If frost may occur, remove the
unit before freezing temperatures set in.
f Always install the water heater vertically with plumbing fittings
pointing downward. Install the water heater near the draw-off
point to minimize pipe runs and thermal losses.
f Taps: Do not use open vented or non-pressurized taps.
The water heater is suitable for under-sink and over-sink installa-
tion.
Typical under-sink installation
D0000089950-a
6
5
13
2
7
4
1 Electrical junction box
2 ½˝ water supply line for faucet installation
3 Shut-off valve
4 Cold water supply
5 Sink
6 Cold valve (right)
7 Hot valve (left)
Note
f Install the water heater flush to the wall. The wall
must have sufficient load bearing capacity.
10.2 Minimum clearances
Ý
Ý
Ý
Ý
D0000079442
f Maintain the minimum clearances to ensure trouble-free oper-
ation of the water heater and facilitate maintenance work.
11. Installation
Factory default settings All DHX Models
Internal temperature limit 140 °F (60 °C)
11.1 Standard wall-mounted installation
11.1.1 Preparing the power cable
4Ǭ–5ǩÝ (125–130 mm)
D0000094559-b
f Prepare the power cable.
11.1.2 Mounting instructions
f Install DHX as close as possible to the hot water draw-off point,
for example, directly underneath the sink.
f Install DHX in a frost free area. If frost may occur, remove unit
before freezing temperatures set in.
f Observe minimum clearances on all sides to ensure unobstruct-
ed servicing if necessary.
f Remove plastic cover by loosening the screw on the bottom.
Lift cover off from the bottom.
D0000094555-b
f Mark the 2drill holes, referencing their position using the
water heater rear panel as a guide.
f Set water heater rear panel aside and drill the 2 marked holes.

INSTALLATION
Installation
ENGLISH
www.stiebel-eltron-usa.com DHX Trend & DHX Plus|15
f Install wall anchors in the wall, then insert and tighten each
mounting screw partially. Screws and plastic wall anchors for
mounting on drywall or wood are provided.
f Hang the unit on the 2 mounting screws, ensuring the rear of
the unit is flush against the wall.
f Once the unit is in position, mount the unit securely to the wall
by fully tightening the 2 mounting screws.
D0000089951-a
11.2 Water connections
!
CAUTION: DO NOT INSTALL IN A BATH ENCLOSURE OR
SHOWER STALL OR CONNECT TO A SALT-REGENERATED
WATER SOFTENER OR A WATER SUPPLY OF SALT
WATER
FOR USE ON AN INDIVIDUAL BRANCH CIRCUIT ONLY
CAUTION: CONNECT ONLY TO A CIRCUIT PROTECTED BY A
CLASS A GROUND FAULT CIRCUIT INTERRUPTER
USE COPPER CONDUCTORS ONLY
USE BONDING CONDUCTOR IN ACCORDANCE WITH THE
CANADIAN ELECTRICAL CODE, PART I
!
Material losses
Carry out all water connection and installation work in
accordance with regulations.
!
Material losses
Excessive heat from soldering on copper pipes near the
DHX may cause damage to the unit or the plastic filter
screen located in the cold water inlet.
NOTICE
The cold water connection to the unit MUST be discon-
nected periodically in order to clean the filter screen.
It is required to use water connections that are easily
detachable such as braided steel flex connectors.
NOTICE
Hard water or water with a high mineral count may dam-
age the unit. Damage to the unit caused by scale or a high
mineral count is not covered under the warranty.
NOTICE
Tankless water heaters such as the DHX Trend are not
required to be equipped with a temperature and pressure
relief valve (T&P). If the local inspector will not pass the
installation without a T&P, it should be installed on the
hot water outlet side of the unit.
11.2.1 Permissible water connection materials
f The DHX’s hot water outlet (left) is designed for connection to
copper tubing, PEX tubing or a braided stainless steel hose
with a ½˝ NPT female tapered thread.
f The plumbing on the cold water inlet side (right) needs to be
such that it can easily be removed to allow access to the inlet
filter screen. The easiest way to achieve this is to use a braided
steel flex connector with a ½˝ female NPT connection.
!
Material losses
If plastic pipework systems are used, take into account the
maximum inlet temperature and the maximum permissible
pressure.
11.2.2 Flow rate
f Ensure that the minimum activation flow rate for switching on
the water heater is met: 0.264 gal (1.0 l/min).
f If the required minimum activation flow rate is not met when
the draw-off valve is fully opened, increase the water line pres-
sure. Minimum supply pressure is 26.1 psi (1.8 bar).
11.2.3 Water connection instructions
!
Material losses
If soldering near the unit is necessary, please direct the
flame away from the housing of the unit in order to avoid
damage. Note that excessive heat from soldering (not rec-
ommended) near the cold water inlet fitting may damage
the plastic filter screen located inside it.
All plumbing work must comply with national and applicable state
and local plumbing codes.
Cold water connection (inlet) is on the right side of the unit, hot
water connection (outlet) is on the left side of unit.
f A pressure reducing valve must be installed if the cold water
supply pressure exceeds 150 psi (10 bar).
f Make certain that the cold water supply line has been flushed
to remove any scale and dirt.
f Install shut-off valve in cold water line as shown in the illus-
tration on page 14. This allows the unit to be easily isolated for
maintenance purposes.

INSTALLATION
Installation
16 | DHX Trend & DHX Plus www.stiebel-eltron-usa.com
D0000094555-b
f Connected braided steel flex connectors (recommended for hot
outlet, required for cold inlet, not supplied) to the twin ½˝ NPT
male connectors.
f Open the shut-off valve in the cold water inlet line.
When all plumbing work is completed, check for leaks and take
corrective action before proceeding.
11.3 Aerator installation at connected faucet
DHX 3.5-1 Trend ships with a 0.5 gpm (1.9 l/min) pressure compen-
sating flow-reducer/aerator. DHX 6-2 Trend ships with a 1.0 gpm
(3.8 l/min) pressure compensating flow-reducer/aerator. For these
models, the aerator must be installed on the faucet the water heater
is connected to. Failure to install the aerator may result in lower
water temperatures than desired.
11.4 Electrical connection
WARNING: Electrocution
Before beginning any work on the electric installation,
be sure that main breaker panel switches are “Off” to
avoid any danger of electric shock. All mounting and
plumbing must be completed before proceeding with
electrical hook-up.
The unit must be properly grounded in accordance with
state and local codes, or in absence of such codes, in
accordance with national electric code or the Canadian
electric code. Failure to electrically ground the product
could result in serious personal injury or death.
!
CAUTION: DO NOT INSTALL IN A BATH ENCLOSURE
OR SHOWER STALL. DO NOT CONNECT TO A
SALT-REGENERATED WATER SOFTENER OR A WATER
SUPPLY OF SALT WATER.
FOR USE ON AN INDIVIDUAL BRANCH CIRCUIT ONLY.
CAUTION: CONNECT ONLY TO A CIRCUIT PROTECTED BY A
CLASS A GROUND FAULT INTERRUPTER
USE BONDING CONDUCTOR IN ACCORDANCE WITH THE CA-
NADIAN ELECTRICAL CODE, PART I
WARNING Electrocution
The connection to the power supply is only permissible as
a permanent connection in conjunction with a ¾˝Romex
clamp. Ensure the water heater can be separated from
the power supply by an isolator that disconnects all poles
with at least 1/8˝(3mm) contact separation.
!Supply this appliance only from a grounded system. A
green terminal (or a wire connector marked “G”, “GR”,
“GROUND”, OR “GROUNDING”) is provided for wiring the
appliance. To reduce the risk of electric shock, connect
this terminal or connector to the grounding terminal of
the electric service or supply panel with a continuous
copper wire in accordance with the electrical installation
code.
!
Material losses
Observe the type plate. The specified rated voltage must
match the supply line voltage.
!
Material losses
The DHX 3.5-1 Trend must only be connected to a 120V elec-
trical supply. Connecting the DHX 3.5-1 Trend to a 208–240V
electrical supply will permanently damage the unit and void
the factory warranty.
f All electrical work must comply with national and applicable
state and local electrical codes.
f The DHX should be connected to a properly grounded dedicat-
ed branch circuit of proper voltage rating. In installations with
several DHX units, each unit requires an independent circuit.
Please refer to the technical data table for the correct wire and
circuit breaker size.
f A 3/4˝ Romex clamp (required, not supplied) should be in-
stalled in the opening located between the hot and cold water
connections. The wire should be fed through the Romex clamp.
The “live” wires must be connected to the slots on the terminal
block marked N and L (DHX 3.5-1 Trend only) or L and L (all
other versions). The ground wire must be connected to the slot
marked with the ground symbol. See section 17.2, “Wiring dia-
grams,” pg. 21.
4Ǭ–5ǩÝ (125–130 mm)
D0000089948-a

INSTALLATION
Commissioning
ENGLISH
www.stiebel-eltron-usa.com DHX Trend & DHX Plus | 17
11.5 Electrical connection with short power cable
If the power cable is not quite long enough, you can install the wiring
block closer to the aperture in the water heater.
f Reposition the wiring block from the top to the bottom. To do
so, unclip the wiring block by pushing it firmly to the left and
pulling it forwards.
D0000095302-b
f Clip the wiring block in at the bottom by pushing it inwards
and to the left until it clicks into place.
11.6 Wiring block
Consult the chart below for the recommended torque amounts on
the wiring block screws.
Screw Size (mm) Min. Torque (N•cm) Min. Torque (lbf•in)
M6 200-250 17.7–22.1
Using the proper torque specifications to secure wire to the wiring
block helps to avoid personal loss or property damage.
12. Commissioning
12.1 Internal anti-scalding protection via jumper slot
For increased safety, the qualified contractor can set an internal an-
ti-scalding temperature limit via the “Tmax” jumper. The anti-scald-
ing protection feature limits the maximum output temperature of
the water heater. This feature overrides the temperature adjust-
ment display on the front cover (both the temperature selection
and temperature limit via software functions). A user can still make
temperature adjustments below the anti-scalding limit using the
display, however, any temperature selected that is higher than the
Tmax limit set will be ignored, and the output temperature will be
limited to the Tmax value.
38°C | 100°F
43°C | 109°F
50°C | 122°F
60°C | 140°F
D0000094558-b
Jumper position Description
38 °C | 100 °F Code-compliant hand washing applications (fac-
tory default setting)
43°C | 109°F Applications where risk of scalding may be a
concern
50 °C | 122 °F DHW for kitchen sink, utility sink, etc.
60 °C | 140 °F Commercial applications (kitchens, etc.), health
code requirements
No jumper Limit 38 °C | 100 °F
f Install the jumper in the required position on the “Tmax” pin
strip.
CAUTION Burns
If the water supplied to the water heater is preheated, the
internal anti-scalding protection and the user-adjustable
temperature limit may be exceeded.
In such cases, limit the temperature with an upstream
central thermostatic valve.
12.2 Initial start-up
Note
During initial start-up, you MUST engage the AE3 safety
switch by depressing the white reset button before supply-
ing power to the water heater. The unit will NOT operate
until the safety switch has been engaged.
PLQ
12
D0000053277
f Open and close all connected draw-off valves at least five times
total. Let water run for at least three minutes, until all air has
been purged from the pipework and the water heater.
f Ensure there are no water leaks from any plumbing
connections.

INSTALLATION
Water heater shutdown
18 | DHX Trend & DHX Plus www.stiebel-eltron-usa.com
12.2.1 Initial AE3 safety switch activation
D0000094561-b
f Engage the AE3 safety switch by firmly pressing the white reset
button until it clicks and fully locks in place (the water heater is
delivered with the safety switch disengaged).
D0000082937
f Connect the programming unit connecting cable plug to the
PCB.
Note
It is essential to plug the connecting cable from the pro-
gramming unit into the PCB before switching on the power.
Otherwise, the programming unit will not function.
D0000073642
f Hook the water heater cover into the water heater back panel
at the top rear. Pivot the cover downwards. Check that the cover
is securely seated at both top and bottom.
f Secure the cover with the screw.
f Remove the protective film from the front panel.
D0000053281
f Switch on the power supply.
f Ensure the programming unit is functioning correctly.
12.2.2 Water heater handover
f Explain the water heater functions to users, and familiarize
them with how it works.
f Make the user aware of potential dangers, especially the risk of
scalding.
f Hand over the instructions.
12.3 Operation with preheated water
The maximum inlet temperature may be limited by installing a
central thermostatic valve. Use the thermostatic valve for central
premixing, for example when operating an tankless water heater
with preheated water. For use in shower operation, the valve must
be set to a maximum of 131°F (55 °C).
12.4 Recommissioning
!
Material losses
To ensure that the Direct Coil™heating system is not dam-
aged following an interruption to the water supply, the
water heater must be restarted by taking the following
steps:
f Disconnect the water heater from the power supply by
turning the connected circuit breaker.
f Open and close all connected draw-off valves at least 5
times, for at least 3 minutes total, until all air has been
purged from the pipework and the water heater.
f Switch the power back ON.
13. Water heater shutdown
f Turn the connected circuit breaker too the “Off” position.
f Drain the water heater (See section 15.1, “Draining the water
heater,” pg. 19").

INSTALLATION
Service information
ENGLISH
www.stiebel-eltron-usa.com DHX Trend & DHX Plus | 19
14. Service information
Connection overview/component overview
1
2
3
5
6
7
4
D0000095301-a
1 Motorized valve
2 Flow sensor
3 High limit safety cut-out, automatic reset, klixon
4 NTC sensor
5 Pin strips for connected load and anti-scalding protection
6 Programming unit plug-in position
7 Diagnostic traffic lights
15. Maintenance
WARNING Electrocution
Before beginning any work on the water heater, be sure
that main breaker panel switches are “Off” to avoid any
danger of electric shock.
15.1 Draining the water heater
The water heater can be drained for maintenance work.
WARNING Burns
Hot water may escape when you drain the water heater.
f Close the shut-off valve in the cold water inlet line.
f Open all draw-off valves.
f Undo the water connections on the water heater.
f Store the dismantled water heater free from the risk of frost,
as water residues remaining inside the water heater can freeze
and cause damage.
15.2 Cleaning the filter screen
WARNING Burns
Hot water may escape when you drain the appliance.
!
Material losses
To ensure that the Direct Coil™heating system is not dam-
aged following an interruption to the water supply, the
water heater must be restarted by taking the following
steps:
f Shut off power to the unit at the breaker panel by
making sure that connected circuit breakers are
“OFF” to avoid any danger of electric shock.
f Open and close all connected draw-off valves at
least 5 times, for at least 3 minutes total, until all air
has been purged from the pipework and the water
heater.
f Switch the power back ON at the breaker panel.
The DHX has a built in sediment filter screen that should be cleaned
periodically:
f Turn off power to the water heater at the circuit breaker.
f Turn off the water supply to the water heater at the shut-off
valve.
f Open a connected hot water tap to relieve built-up pressure
(this will minimize leakage when removing the connection from
the cold water inlet).
f Disconnect the braided steel flex connector from the cold water
inlet fitting (right).
f To remove the filter screen from the bottom of the cold water
inlet, carefully insert a flathead screwdriver just above the
plastic lip of the filter screen, and gently pull downward.
f Clean the filter screen, re-insert securely into the cold water
inlet fitting, and reconnect the braid steel flex connector to the
cold water inlet.
f Open the cold water supply shut-off valve.
f Vent the air from pipes and the water heater by opening and
closing all connected draw-off valves at least 5 times, for at
least 3 minutes total, until all air has been purged from the
pipework and the water heater.
f Turn on circuit breaker to bring electrical power to the unit.

INSTALLATION
Troubleshooting
20 | DHX Trend & DHX Plus www.stiebel-eltron-usa.com
16. Troubleshooting
WARNING Electrocution
Never remove or reinstall the water heater’s cover
unless the electricity servicing the unit is turned off.
Failure to do so could result in personal injury or death.
WARNING Electrocution
To test the water heater using the internal diagnostic
lights, it must be connected to the power supply.
When testing with the cover off, never touch any part
of the water heater. Doing so could result in serious
personal injury or death.
Note
When testing the water heater using the diagnostic lights,
water must be flowing through the unit.
Diagnostic lights
Red Lights up in the event of an error
Yellow Lights up in heating mode/flashes when output limit
reached
Green Flashing: Water heater connected to power supply
Diagnostic lights Problem Cause Solution
No LED is lit The water heater does not
heat up
There is no power Check to ensure the connected circuit breaker in the main
breaker panel hasn’t tripped. Reset if necessary
The PCB is faulty Replace the PCB
Green flashing, yellow
off, red off
No DHW The shower head/aerator is scaled up Descale or replace the shower head/aerators if necessary
The filter screen in the cold water inlet is dirty Clean the filter screen
The flow sensor is not plugged in Connect the cable to the PCB
The flow sensor is faulty Replace the flow sensor
The PCB is faulty Replace the PCB
Green flashing, yellow
on, red off
The display on the program-
ming unit is off
There is a loose cable between the PCB and the pro-
gramming unit
Check the cable and plug the cable into the programming
unit and/or PCB
The cable of the programming unit is faulty Check the cable and replace if necessary
The programming unit PCB is faulty Replace the programming unit, only available with a new
heater cover
The PCB is faulty Replace the PCB
Green flashing, yellow
on, red off
The outlet temperature does
not match the set value
The programming unit was not plugged in before
power was switched on
Perform a reset by switching off the power to the water
heater
The outlet sensor is faulty Replace the outlet sensor
The tap is faulty Replace the tap
The heating system is faulty Replace the heating system
The PCB is faulty Replace the PCB
Plus models only:
Green flashing, yellow
The outlet temperature does
not match the set value
Motorized valve limit reached Reduce the set temperature
flashing, red off Motorized valve is faulty Replace the motorized valve
Green flashing, yellow
off, red on
No DHW Air detected Continue draw-off for >1 minute
Diagnostic lights Display readout Problem Cause Solution
Plus models only:
Green flashing, yellow
off, red on
Wrench flashes (displays
E1 and wrench in menu
“Fault code display”)
No DHW AE3 safety switch not activated during
commissioning
Activate AE3 safety switch by pressing the reset button
firmly. See section 12.2.1, “Initial AE3 safety switch acti-
vation,” pg. 18
AE3 safety switch triggered by
self-resetting high limit safety cut-out
Klixon
Check high limit safety cut-out, Klixon (plug-in connec-
tion, connecting cable); activate AE3 safety switch
AE3 safety switch responds again after
high limit safety cut-out Klixon has been
checked; high limit safety cut-out faulty
Replace high limit safety cut-out Klixon activate AE3 safe-
ty switch and draw off water at the maximum set value
for >1 min
Safety switch responds again; PCB faulty Replace the PCB
Wrench flashes (displays
E2 and wrench in menu
“Fault code display”)
No DHW PCB faulty (lead break or short circuit in
inlet sensor)
Replace the PCB
Wrench flashes (displays
E3 and wrench in menu
“Fault code display”)
No DHW Short circuit in outlet sensor Check the outlet sensor, replace if necessary