STIEBEL ELTRON DHC 3-1 Instruction Manual

OPERATION AND INSTALLATION
UTILISATION ET INSTALLATION
OPERACIÓN E INSTALACIÓN
TANKLESS ELECTRIC WATER HEATER | CHAUFFE-EAU ÉLECTRIQUE SANS ACCUMULATEUR |
CALENTADOR DE AGUA INSTANTANEOS SIN TANQUE
» DHC 3-1
» DHC 3-2
» DHC 4-2
» DHC 4-3
» DHC 5-2
» DHC 6-2
» DHC 8-2
» DHC 9-3
» DHC 10-2
84335
The DHC series is tested and
certified by WQA against
NSF/ANSI 372 for lead free
compliance.

2|DHC WWW.STIEBEL-ELTRON.COM
CONTENTS | OPERATION
OPERATION
1. General information
Note
Read these instructions carefully before using the ap-
pliance and familiarize yourself with its functions. Keep
these instructions safe. Pass on the instructions to a new
user if required.
OPERATION
1. General information �����������������������������������������2
1.1 Safety information����������������������������������������������� 2
1.2 Other symbols in this document������������������������������ 2
2. Safety����������������������������������������������������������2
2.1 Intended use������������������������������������������������������ 3
2.2 General Information��������������������������������������������� 3
2.3 Safety Precautions����������������������������������������������� 3
2.4 Test symbols ������������������������������������������������������ 3
3. General��������������������������������������������������������3
INSTALLATION
4. Mounting the unit ��������������������������������������������4
5. Water connections �������������������������������������������4
6. Electrical connection�����������������������������������������5
7. Putting the water heater into operation�������������������5
8. Normal maintenance�����������������������������������������5
9. Technical Data ������������������������������������������������6
9.1 Wiring diagram �������������������������������������������������� 6
9.2 Data table ��������������������������������������������������������� 7
10. Temperature increase above ambient water
temperature ��������������������������������������������������8
11. Troubleshooting ����������������������������������������������9
12. Spare parts ������������������������������������������������� 10
WARRANTY | ENVIRONMENT AND RECYCLING
1.1 Safety information
1.1.1 Structure of safety information
KEYWORD Type of risk
Here, possible consequences are listed that may re-
sult from not observing the safety information.
 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 Description
DANGER If this information is not observed, it will result in serious
injury or death.
WARNING If this information is not observed, it can result in serious
injury or death.
CAUTION If this information is not observed, it can lead to medium
or minor injury.
1.2 Other symbols in this document
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 notes carefully.
Symbol
!Damage to the appliance and environment
Appliance disposal
 This symbol indicates that you have to do something. The ac-
tion you need to take is described step by step.
2. Safety
Observe the following safety information and regulations.
Operate the appliance only when fully installed and with all safety
equipment fitted.

OPERATION
GENERAL
ENGLISH
WWW.STIEBEL-ELTRON.COM DHC|3
2.1 Intended use
The appliance is intended for heating domestic hot water and can
supply one draw-off point.
Any other use beyond that described shall be deemed inappro-
priate.
Observation of these instructions is also part of the correct use
of this appliance.
2.2 General Information
This appliance is designed for domestic use. It can be used safely
by untrained persons. The appliance can also be used in a non-
domestic environment, e.g. in a small business, as long as it is
used in the same way.
Read this entire manual. Failure to follow all the guides, instruc-
tions and rules could cause personal injury or property damage.
Improper installation, adjustment, alteration, service and use of
this appliance can result in serious injury.
This appliance 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 re-
sponsibility of the installer. Failure to comply with the installation
and operating instructions or improper use voids the warranty.
Save these instructions for future reference. Installer should leave
these instructions with the consumer.
If you have any questions regarding the installation, use or opera-
tion of this water heater, or if you need any additional installation
manuals, please call our technical service line, see last side.
2.3 Safety Precautions
!
DANGER Injury
Please read and follow these instructions.
Failure to follow these instructions could result in seri-
oius personal injury or death.
!
Damage to the appliance and the environment
The appliance must be installed by a licensed electri-
cian and plumber. The installation must comply with all
national, state and local plumbing and electric codes.
Service of the appliance must be performed by qualified
service TECHNICIANS.
DANGER Electrocution
Before proceeding with any installation, adjustment. al-
teration, or service of this appliance all circuit breakers
and disconnect switches servicing the appliance must
be turned off. Failure to do so could result in serious
personal injury or death.
DANGER Electrocution
Never remove the appliance‘s cover unless the electric-
ity servicing the appliance is turned off. Failure to do so
could result in personal injury or death.
DANGER Electrocution
The appliance must be properly grounded. Failure to
electrically ground the product could result in serious
personal injury or death.
DANGER Burns
Water temperatures over 125°F (52 °C)can cause severe
burns instantly or death from scalding.
!
WARNING Injury
The appliance may be used by children aged 8 and up
and persons with reduced physical, sensory or mental
capabilities or a lack of experience 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 appliance.
Children must never clean the appliance or perform user
maintenance unless they are supervised.
2.4 Test symbols
See type plate on the appliance.
3. General
The DHC tankless water heater differs from conventional storage
type water heaters in several ways. It does not store hot water.
Instead, water is heated instantaneously as it flows through the
unit. The powerful heating elements are activated by a flow switch
as water is drawn from a hot water faucet connected to the DHC.
Due to the absence of stand-by losses, the DHC has greater energy
efficiency than storage type water heaters.
The temperature of the hot water delivered by the DHC depends
on the wattage of the heating element, the temperature of the
incoming cold water, and the water flow rate through the unit.
In order for the DHC to operate properly, it must be carefully
matched to the application.
In case you have questions regarding the way you plan to use the
DHC, please call our technical service line at 800-582-8423 (USA and
Canada). For service outside the U.S. and Canada, please call us at
USA 413-247-3380. You can also e-mail us at info@stiebel-eltron-
usa.com or fax us at 413-247-3369.
The DHC can be used for hand washing type applications in the
U.S. and Canada:
- Restroom sinks in commercial/industrial facilities and homes
- Kitchen areas in commercial /industrial facilities and homes
- Cabins
- Special uses in photo developing shops, laboratories etc.
The DHC can also be used for whole apartments and homes in
warm climate zones such as the Caribbean region, Central Amer-
ica and Mexico due to the higher ambient water temperatures.

4|DHC WWW.STIEBEL-ELTRON.COM
INSTALLATION
MOUNTING THE UNIT
INSTALLATION
4. Mounting the unit
26�02�02�0330
7
6
14
3
2
8
5
1 Electrical junction box
2 Water supply line for faucet installation
3 3/8“ compression-T
4 Shut-off valve
5 1/2“ main pipe
6 Sink
7 Cold valve (right)
8 Hot valve (left)
DANGER Electrocution
UNIT MUST BE INSTALLED IN A VERTICAL POSITION WITH
THE WATER FITTINGS POINTING DOWNWARD. DO NOT
INSTALL UNIT WHERE IT WOULD ROUTINELY BE SPLASHED
WITH WATER. ELECTRIC SHOCK MAY RESULT.
1. Install DHC as close as possible to the hot water draw-off
point, for example, directly underneath the sink or next to
the shower stall.
2. Install DHC in a frost free area. If frost may occur, remove
unit before freezing temperatures set in.
3. Leave a minimum of 5“ of clearance on all sides for
servicing.
4. Remove plastic cover.
26�02�02�1360
5. Mount unit securely to wall by putting two screws through
mounting holes. Screws and plastic wall anchors for mount-
ing on masonry or wood are provided.
26�02�02�033126�02�02�1355
5. Water connections
1. All plumbing work must comply with national and applicable
state and local plumbing codes.
2. A pressure reducing valve must be installed if the cold water
supply pressure exceeds 150 PSI (10 bar).
3. Make certain that the cold water supply line has been flushed
to remove any scale and dirt.
4. Install isolating valve in cold water line as shown in illustra-
tion. This allows the unit to be isolated for maintenance
purposes.
5. Cold water connection (inlet) is on the right side of the unit,
hot water connection (outlet) is on the left side of unit.
Note
EXCESSIVE HEAT FROM SOLDERING ON COPPER PIPES
NEAR THE DHC MAY CAUSE DAMAGE.

ENGLISH
WWW.STIEBEL-ELTRON.COM DHC|5
INSTALLATION
ELECTRICAL CONNECTION
6. Tankless water heaters such as the DHC are not required to
be equipped with a Pressure and Temperature Relief Valve
(PTRV). If the local inspector will not pass the installation
without a PTRV, it should be installed on the hot water outlet
side of unit.
7. In case you are connecting to 1/2“ water pipe, solder 1/2“
NPT tapered female adapter by copper on ends of cold and
hot water lines. In case you are connecting to 3/8“ water
pipe, use a 1/2“ female pipe thread by 3/8“ compression
adapter. Braided flexible connectors will work as well. Con-
nect cold and hot water lines to the unit.
8. When all plumbing work is completed, check for leaks and
take corrective action before proceeding.
6. Electrical connection
DANGER Electrocution
BEFORE BEGINNING ANY WORK ON THE ELECTRIC IN-
STALLATION, BE SURE THAT MAIN BREAKER PANEL
SWITCH IS „OFF“ TO AVOID ANY DANGER OF ELEC-
TRIC SHOCK. ALL MOUNTING AND PLUMBING MUST
BE COMPLETED BEFORE PROCEEDING WITH ELECTRI-
CAL HOOK-UP. WHERE REQUIRED BY LOCAL, STATE OR
NATIONAL ELECTRICAL CODES THE CIRCUIT SHOULD BE
EQUIPPED WITH A „GROUND FAULT INTERRUPTER“.
1. All electrical work must comply with national and applicable
state and local electrical codes.
2. The DHC should be connected to a properly grounded dedi-
cated branch circuit of proper voltage rating. In installations
with several DHC units, each unit requires an independent
circuit. Please refer to the technical data table for the correct
wire and circuit breaker size.
3. The wire must be fed through the rubber seal located be-
tween the hot and cold water connections. Then feed wires
through strain relief clamp and tighten clamp down on wire.
The „live“ wires must be connected to the slots on the ter-
minal block marked N and L (DHC 3-1 only) or L and L (all
other versions). The ground wire must be connected to slot
marked with the ground symbol.
4. Reinstall plastic cover.
26�02�02�0469
DANGER Electrocution
AS WITH ANY ELECTRIC APPLIANCE, FAILURE TO ELEC-
TRICALLY GROUND UNIT MAY RESULT IN SERIOUS INJURY
OR DEATH.
7. Putting the water heater into
operation
!
WARNING
OPEN HOT WATER FAUCET FOR A FEW MINUTES UNTIL
WATER FLOW IS CONTINUOUS AND ALL AIR IS PURGED
FROM WATER PIPES. THE UNIT’S PLASTIC COVER MUST
BE INSTALLED BEFORE THE CIRCUIT BREAKER IS TURNED
ON.
1. Turn on circuit breaker to bring electrical power to the unit.
2. Open hot water faucet to a degree so that water flow is „typi-
cal“ i.e. until the water flow is the same as that encountered
during normal use.
3. Wait twenty seconds until temperature has stabilized. Then
check water temperature. If temperature is too low, the
water flow rate needs to be reduced. In order to do this,
turn off the unit’s circuit breaker, remove the cover and turn
the flow adjustment screw shown in illustration clockwise
1/2 turn (180 degrees). Then reinstall plastic cover, turn
on circuit breaker and check water temperature. This pro-
cedure should be repeated until the desired temperature is
achieved. In case the water temperature is too high, turn the
flow adjustment screw counter clockwise in the same man-
ner until the desired temperature is achieved. The arrows in
illustration refer to the water temperature.
4. In order to obtain temperature control at a single spout mix-
er-type faucet, restrict cold water flow to faucet by partially
closing the cold water shut-off valve under the sink until cold
water and hot water flow rates are approximately the same.
8. Normal maintenance
STIEBEL ELTRON DHC tankless heaters are designed for a very long
service life. Actual life expectancy will vary with water quality and
use. The unit itself does not require any regular maintenance.
However, to ensure consistent water flow, it is recommended
to periodically remove scale and dirt that may build up at the
aerator of the faucet or in the shower head. Also, the DHC has
a built in filter screen that should be cleaned from time to time.
In order to do this, turn off the cold water supply at the isolating
valve and remove the ground wire. Twist cold water supply tube
counterclockwise by 90° and pull towards bottom of unit. Clean
screen and put the screen, the cold water supply tube and the
ground wire back into their original position. Please be sure that
the ground wire is reinstalled and that ground screw is securely
tightened after this procedure.
Note
OTHER THAN THE FILTER SCREEN, THE DHC DOES NOT
CONTAIN ANY PARTS SERVICEABLE BY THE LAY PERSON.
IN CASE OF MALFUNCTION PLEASE CONTACT A LICENSED
PLUMBER OR ELECTRICIAN.

6|DHC WWW.STIEBEL-ELTRON.COM
INSTALLATION
TECHNICAL DATA
9. Technical Data
b01
c06 c01
c01
c06
38 (1.5")
360 (14.17")
200 (7.88")
100 (3.94") 110 (4.33")
273 (10.75")75 (2.953")
8 (0.315")
D0000021558
b01 electrical supply cable
c01 cold water connection " NPT 1/2
c06 hot water connection " NPT 1/2
9.1 Wiring diagram
DHC 3-2, DHC 4-2, DHC 5-2
2/GRD ~ 208 / 240 V
DHC 4-3
2/GRD ~ 277 V
LL
V
85�02�02�0008
DHC 6-2, DHC 8-2, DHC 10-2
A 2/GRD ~ 208 / 240 V
DHC 9-3
A 2/GRD ~ 277 V
DHC 3-1
B 1/N/GRD ~ 120 V
V
LL
NL
85�02�02�0009
A
B

ENGLISH
WWW.STIEBEL-ELTRON.COM DHC|7
INSTALLATION
TECHNICAL DATA
9.2 Data table
DHC 3-1 DHC 3-2 DHC 4-2 DHC 4-3 DHC 5-2 DHC 6-2 DHC 8-2 DHC 9-3 DHC 10-2
074050
234452
074052 074053 074051 074054 074424
234453
074055
234454
232204 074056
234455
Electrical details
Voltage V120 208 240 208 240 277 208 240 208 240 208 240 277 208 240
Wattage kW 3.0 2.5 3.5 2.9 3.8 4.5 3.6 4.8 4.5 6.0 5.4 7.2 97.2 9.6
Ampere A25 12 14 14 16 17 18 20 22 25 26 30 32.5 35 40
Min. required circuit breker size A 30 15 20 20 20 20 30 30 30 30 30 40 40 50 50
Required wire size AWG
Copper
10 12 12 12 10 10 8 8 8
Power connection 1/N/GRD 2/GRD 2/GRD 2/GRD 2/GRD 2/GRD 2/GRD 2/GRD 2/GRD
Connections
Water connection 1/2“ NPT 1/2“ NPT 1/2“ NPT 1/2“ NPT 1/2“ NPT 1/2“ NPT 1/2“ NPT 1/2“ NPT 1/2“ NPT
Total alkaline earths mol/m³ 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5
Total hardness (H2O) Degree d 14 14 14 14 14 14 14 14 14
Hardness range 2 (average
hardness)
2 (average
hardness)
2 (average
hardness)
2 (average
hardness)
2 (average
hardness)
2 (average
hardness)
2 (average
hardness)
2 (average
hardness)
2 (average
hardness)
Hydraulic data
Rated capacity l0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5
Rated capacity gal 0.13 0.13 0.13 0.13 0.13 0.13 0.13 0.13 0.13
Values
Max. permissible inlet tem-
perature
°C 30 30 30 30 30 30 30 30 30
Max. permissible inlet tem-
perature
°F 86 86 86 86 86 86 86 86 86
ON l/min 1.2 1.2 1.6 1.6 1.6 1.8 2.6 3.0 3.0
ON GPM 0.32 0.32 0.43 0.43 0.43 0.48 0.69 0.8 0.8
Pressure drop at flow rate MPa 0.023 0.023 0.023 0.023 0.023 0.023 0.025 0.03 0.03
Pressure drop at flow rate PSI 2.88 2.88 2.88 2.88 2.88 2.88 3.13 3.75 3.75
Flow rate for pressure drop l/min 1.2 1.2 1.6 1.6 1.6 1.8 2.6 3.0 3.0
Flow rate for pressure drop GPM 0.32 0.32 0.43 0.43 0.43 0.48 0.69 0.8 0.8
DHW delivery l/min 1.2 1.2 1.6 1.6 1.6 1.8 2.6 3.0 3.0
DHW delivery GPM 0.32 0.32 0.43 0.43 0.43 0.48 0.69 0.8 0.8
Δϑif presented K36 30 34 40 43 48 30 43 34
Application limits
Max. permissible pressure MPa 1 1 1 1 1 1 1 1 1
Max. permissible pressure PSI 150 150 150 150 150 150 150 150 150
Test pressure MPa 2 2 2 2 2 2 2 2 2
Test pressure PSI 300 300 300 300 300 300 300 300 300
Versions
IP-Rating IP25 IP25 IP25 IP25 IP25 IP25 IP25 IP25 IP25
Material of the pressure vessel Copper Copper Copper Copper Copper Copper Copper Copper Copper
Heating system Tubular
heater
Tubular
heater
Tubular
heater
Tubular
heater
Tubular
heater
Tubular
heater
Tubular
heater
Tubular
heater
Tubular
heater
Cap and back panel Plastic Plastic Plastic Plastic Plastic Plastic Plastic Plastic Plastic
Colour white white white white white white white white white
Colour white white white white white white white white white
Dimensions
Height mm 360 360 360 360 360 360 360 360 360
Height in 14.17 14.17 14.17 14.17 14.17 14.17 14.17 14.17 14.17
Width mm 200 200 200 200 200 200 200 200 200
Width in 7.88 7.88 7.88 7.88 7.88 7.88 7.88 7.88 7.88
Depth mm 100 100 100 100 100 100 100 100 100
Depth in 4.33 4.33 4.33 4.33 4.33 4.33 4.33 4.33 4.33
Weights
Weight kg 2.1 2.1 2.1 2.1 2.1 2.4 2.4 2.4 2.4
Weight lb 4.6 4.6 4.6 4.6 4.6 4.6 4.6 4.6 4.6
- Suitable for supply with cold water
- Tankless water heaters are considered a non-continuous load
- Conductors should be sized to maintain a voltage drop of less
than 3 % under load

8|DHC WWW.STIEBEL-ELTRON.COM
INSTALLATION
TEMPERATURE INCREASE ABOVE AMBIENT WATER TEMPERATURE
10. Temperature increase above
ambient water temperature
[ °F ]
Typ kW GPM (gallon per minute)
0.32 0.42 0.48 0.5 0.69 0.75 0.79 1.0 1.5 2.0
DHC 3-1 3.0 65 49 43 41 30 27 26 20 14 10
DHC 3-2 2.5 54 40 35 34 25 23 21 17 11 9
3.3 71 53 47 45 33 30 28 22 15 11
DHC 4-2 2.9 –47 41 40 29 26 25 20 13 10
3.8 –61 54 52 38 35 33 26 17 13
DHC 4-3 4.5 –73 64 61 45 41 39 31 20 15
DHC 5-2 3.6 –58 51 49 36 33 31 25 16 12
4.8 –77 68 65 48 44 41 33 22 16
DHC 6-2 4.5 ––64 61 45 41 39 31 20 15
6.0 ––85 82 60 55 52 41 27 20
DHC 8-2 5.4 ––––54 49 46 37 25 18
7.2 ––––7165 62 49 33 25
DHC 9-3 9.0 ------77 58 41 31
DHC 10-2 7.2 ––-–––62 49 33 25
9.6 ––-–––82 65 44 33
Min. water flow to activate unit
[ °C ]
Typ / Type kW l/min
1.2 1.6 1.8 2.0 2.6 3.0 4.0 5.0 7.5
DHC 3-1 3.0 36 27 24 22 17 14 11 9 6
DHC 3-2 2.5 30 22 20 18 14 12 975
3.3 39 30 26 24 18 16 12 9 6
DHC 4-2 2.9 –26 23 21 16 14 10 8 6
3.8 –34 30 27 21 18 14 11 7
DHC 4-3 4.5 –40 36 32 25 22 16 13 9
DHC 5-2 3.6 –32 29 26 20 17 13 10 7
4.8 –43 38 34 26 23 17 14 9
DHC 6-2 4.5 – – 36 32 25 22 16 13 9
6.0 – – 48 43 33 29 22 17 11
DHC 8-2 5.4 ––––30 26 19 15 10
7.2 ––––40 34 26 21 14
DHC 9-3 9.0 -----43 32 26 17
DHC 10-2 7.2 –––––34 26 21 14
9.6 –––––46 34 28 18
Min. water flow to activate unit

ENGLISH
WWW.STIEBEL-ELTRON.COM DHC|9
INSTALLATION
TROUBLESHOOTING
11. Troubleshooting
Symptom Possible cause Solution
No hot water but audible click can be heard when
water is turned on
circuit breaker off circuit breaker on.
safety thermal cut-out tripped reset thermal cut-out.
No hot water and no audible click can be heard when
water is turned on
water flow too low to activate flow switch clean faucet aerator.
open shut-off valve completely.
open flow adjustment screw.
clean filter screen at DHC unit (see figure “Spare
parts”).
Water not warm enough water flow too high reduce wter flow, close flow agjusment screw.
voltage too low supply correct voltage to unit.
If you are not able to resolve a problem please contact us toll
free at 800-582-8423 before removing the unit from the wall.
STIEBEL ELTRON is happy to provide technical assistance. In most
instances, we can resolve the problem over the phone.
Open flow adjustment screw
26�02�02�1358
Reset button from safety thermal cut out
26�02�02�1357

10|DHC WWW.STIEBEL-ELTRON.COM
INSTALLATION
SPARE PARTS
12. Spare parts
No. Spare part DHC 3-1 DHC 3-2 DHC 4-2 DHC 4-3 DHC 5-2 DHC 6-2 DHC 8-2 DHC 9-3 DHC 10-2
1Heating system 165889 167769 167770 165890 167771 171117 167772 296874 167773
2 Flow switch 165273 165273 162162 162162 162162 171105 162164 162465 162165
3Thermostat 162472 162472 162472 162472 162472 162472 162472 162472 162472
4Switch 168026 168026 168026 168026 168026 168026 168026 168026 168026
5Housing (back) 165891 165891 165891 165891 165891 165891 165891 165891 165891
6Plumbing connection 165893 165893 165893 165893 165893 165893 165893 165893 165893
7Housing (front) 165892 165892 165892 165892 165892 165892 165892 165892 165892
8 Safety thermal cut out 162474 162474 162474 162474 162474 162474 162474 162474 162474
9Wiring block 026010 026010 026010 026010 026010 026010 026010 026010 026010
10 Copper tube 162314 162314 162314 162314 162314 162314 162314 162314 162314
11 Module chassis 162462 162462 162462 162462 162462 162462 162462 162462 162462
12 Wire strain relief clamp 055754 055754 055754 055754 055754 055754 055754 055754 055754
13 Filter screen 252430 252430 252430 252430 252430 252430 252430 252430 252430
D0000043978
4
7
1
3
2
10
5
6
13
9
12
8
11