Bosch AE7.2 Technical Document

Installation Manual and Operating Instructions
Electric water heaters
AE 3.4/7.2/9.5 kW
en Installation Manual and Operating Instructions 2
es Instrucciones de instalación y funcionamiento 18
fr Instructions d'installation et d'utilisation 33
6 720 800 537 (2011/09) US
IMPORTANT: This booklet should be given to the customer after installation and demonstration.
For Service & Installation contact:
BOSCH Thermotechnology Corp.
50 Wentworth Avenue, Londonderry
NH 03053
Phone: [phone]
www.bosch-climate.us

Table of contents
6 720 800 537 (2011/09)
2
Table of contents
1 Explanation of Symbols and Important Safety
Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1 Explanation of symbols . . . . . . . . . . . . . . . 3
1.2 Important Safety Instructions . . . . . . . . . . 3
2 Information about the heater . . . . . . . . . . . . . . . 4
2.1 Disclaimer . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1.1 Approval number . . . . . . . . . . . . . . . . . . . . 4
2.2 Technical identification code . . . . . . . . . . 4
2.3 Package contents . . . . . . . . . . . . . . . . . . . 4
2.4 Model name and number identification . . 4
2.5 General description . . . . . . . . . . . . . . . . . . 5
2.6 Electrical diagram . . . . . . . . . . . . . . . . . . . 6
2.7 Function . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3 Regulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.1 Important information . . . . . . . . . . . . . . . . 9
4.1.1 Freeze prevention . . . . . . . . . . . . . . . . . . . 9
4.2 Installing the AE 3.4/7.2/9.5 . . . . . . . . . . . 9
4.3 Water connections . . . . . . . . . . . . . . . . . 10
4.3.1 Water quality . . . . . . . . . . . . . . . . . . . . . . 10
4.4 Electrical connections . . . . . . . . . . . . . . . 10
4.5 Securing the unit to the wall . . . . . . . . . . 12
4.5.1 Deciding the position . . . . . . . . . . . . . . . 12
4.5.2 Deciding the wiring route . . . . . . . . . . . . 12
4.5.3 Mounting on the wall . . . . . . . . . . . . . . . 12
5 Starting up the AE 3.4/7.2/9.5 . . . . . . . . . . . . . 14
5.1 Sink . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.2 Adjusting the flow . . . . . . . . . . . . . . . . . . 14
6 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . 15
6.1 For the Installer . . . . . . . . . . . . . . . . . . . . 15
6.2 For the User . . . . . . . . . . . . . . . . . . . . . . 16
7 Interior components and parts list . . . . . . . . . 17

Explanation of Symbols and Important Safety Instructions
6 720 800 537 (2011/09)
3
1 Explanation of Symbols and Important Safety Instructions
1.1 Explanation of symbols
Warnings
Signal words at the beginning of a warning are used to
indicate the type and seriousness of the ensuing risk if
measures for minimizing damage are not taken.
•NOTE indicates that minor damage to property may
occur.
•CAUTION indicates possible minor to medium
personal injury.
•WARNING indicates possible severe personal injury.
•DANGER indicates that severe personal injury may
occur.
Important information
Additional symbols
1.2 Important Safety Instructions
When using this electrical equipment, basic safety
precautions should always be followed, including the
following:
BRead and follow all instructions.
BThis appliance must be grounded.
BDisconnect this product from the electrical supply
before cleaning, servicing or removing the cover.
BTo reduce the risk of injury, close supervision is
necessary when the product is used near children or
elderly persons.
BWarning: Do not install the heater in a location where
it may be subject to freezing.
BWarning: Do not install a check valve or any other
types of back flow preventer within six feet of the cold
water inlet.
BThe electrical installation must conform to current
National Electrical Codes.
BWarning: Do not switch the heater on if you suspect
that it may be frozen. Wait until you are sure that it
has completely thawed cut.
BThe AE 3.4/7.2/9.5 is designed to heat potable cold
water for domestic purposes. Contact Bosch
Thermotechnology before specifying or installing the
appliance in any other application.
Additional Canadian Safety Instructions
•A green terminal (or wire connector marked "G", "GR",
"GROUND", or "GROUNDING") is provided within the
control box. To reduce the risk of electric shock,
connect this terminal or connector to the grounding
terminal of the electric service of supply panel with a
continuous copper wire in accordance with the
Canadian Electrical Code, Part I.
•This product shall be protected by a Class A ground
fault circuit interrupter.
Safe these instructions
BKeep this guide in a safe place once your AE 3.4/7.2/
9.5 unit has been installed.
BYou may need to refer to it for general instructions or
future maintenance.
Warnings are indicated in the text by a
warning triangle and a gray background.
In case of danger due to electric shock, the
exclamation point on the warning triangle is
replaced with a lightning symbol.
Important information that presents no risk
to people or property is indicated with this
symbol. It is separated by horizontal lines
above and below the text.
Symbol Meaning
BSequence of steps
→ Cross-reference to other points in this
document or to other documents
•Listing/list entry
–Listing/list entry (2nd level)
Table 1

Information about the heater
6 720 800 537 (2011/09)
4
2 Information about the heater
2.1 Disclaimer
2.1.1 Approval number
Commonwealth of Massachusetts
As a condition of installing this product in the
Commonwealth of Massachusetts a pressure relief valve
shall be installed on the cold water side, by a licensed
plumber MGL 142 Section 19.
(Approval number: P1-09-25).
2.2 Technical identification code
US Electronic Instantaneous
3Maximum output (kW)
MMechanical temperature control
WWall hung
IIndoor
HHorizontal installation
BWater connections
2.3 Package contents
•Electric water heater
•4 No. 8 wood screws
2.4 Model name and number
identification
US 3 - 1 M W I H B
US 7 - 1 M W I H B
US 9 - 1 M W I H B
Table 2
Model Name Model Number
AE 3.4/7.2/9.5 US 3-1 Pro M W I H B
AE 3.4/7.2/9.5 US 7-1 Pro
M W I H B
AE 3.4/7.2/9.5 US 9-1 Pro M W I H B
Table 3

Information about the heater
6 720 800 537 (2011/09)
5
2.5 General description
Fig. 1
1Mounting hole
2Heat exchanger tube
3Thermal cut-out (manual re-set)
4Heating elements
5Terminal block
6Cable rear entry
7Ground stud
8Cable clamp
9Filter and water pipe mounting
10 Cable side entry
11 Flow switch
12 Power selector
13 Cover fixing screw
14 Neon light
Outlet Inlet

Information about the heater
6 720 800 537 (2011/09)
6
2.6 Electrical diagram
Fig. 2 Internal wiring plan
DANGER: Risk of electric shock!
BAlways switch off the electrical supply to
the unit before removing cover or
performing any maintenance and service.
Heating elements
Electrical
supply
Manual reset Thermal cut-out
Neon
Power selector
and Flow switch

Information about the heater
6 720 800 537 (2011/09)
7
2.7 Function
How the water heater works:
•Water comes in through the cold water inlet.
•The flow switch senses how much water is passing
through the unit. If it detects more than the preset
level, the unit’s heating elements switch on. This is
shown by the neon light glowing.
•The water is heated instantly as it passes through the
copper heat exchanger tube.
The temperature of the water coming out of the unit
depends on:
•The voltage of the electrical supply,
•The temperature of the incoming water supply,
•The setting of the power selector,
•The flow rate,
•The power rating of the unit.
•Depending on the region of the country, the
temperature of the water supply can vary between
40 °F in winter to 70 °F in summer, with an average of
50 °F.
Fig. 3
AManual reset thermal cut out
The table below shows the rise in water temperature you
can expect from the unit:
Manual reset thermal cut-out
The unit has a thermal cut-out (Fig. 1) which is mounted
on the heat exchanger tube. This will switch off the
heater elements if the water temperature goes above
194 °F.
If the cut-out trips it will need to be reset manually inside
the unit. This cut-out will only operate in exceptional
circumstances (Fig. 3). Call your service person or Bosch
Water Heating if this happens frequently.
The heater is designed for cold water supply
only. Do not supply with pre-heated water.
Model Volts Amps
Element
Resistance
High
Setting
Low
Setting
Temperature Rise (deg F) at Flow Rate
(GPM)
0,5
GPM
0,75
GPM
1,0
GPM
1,5
GPM
2,0
GPM
2,5
GPM
US3 120-110 27 2x8 Ω3,4-
3,0kW
- 41F 28F 20F NA NA NA
US7 240-220 15 1x16 Ω- 3,6-
3,05kW
NA 32F 24F 16F 12F NA
US7 240-220 30 2x16 Ω7,2-
6,1kW
- NA 63F 48F 32F 24F NA
US9 208 18 1x12 Ω- 3,5kW NA 32F 24F 16F 12F NA
US9 208 35 2x12 Ω7,1kW - NA 64F 48F 32F 24F NA
US9 240 20 1x12 Ω- 4,75kW NA 42F 32F 21F 16F NA
US9 240 40 2x12 Ω9,5kW - NA 84F 64F 42F 32F NA
Table 4

Regulations
6 720 800 537 (2011/09)
8
3 Regulations
Any local by-laws and regulations pertaining to
installation and use of electric water heater appliances
must be observed. Please refer to the laws that should
be attended in your country.
•The electrical installation must conform to current
National Electrical Codes.
•To reduce the risk of electrical shock, connect this
terminal or connector to the grounding terminal of the
electrical service of supply panel with a continuous
copper wire in accordance with the Canadian
Electrical Code, Part I.
•This product shall be protected by a Class A ground
fault circuit interrupter.
•In the Commonwealth of Massachusetts a licensed
plumber or electrician must perform the installation.
(Approval number: P1-09-25).
•In the Commonwealth of Massachusetts a pressure
relief valve shall be installed on the cold water side by
a licensed plumber. (MGL 142 Section 19, Approval
number P1-09-25).
•The unit must be wired by a qualified electrician, in
accordance with the current version of the National
Electrical Code US) or Canadian Electric Code
(Canada).
•When the heater is not within sight of the electrical
circuit breakers, a circuit breaker lockout or
additional local means of disconnection for all non-
grounded conductors must be provided that is within
sight of the appliance. (Ref NEC 422.31.).
•The power cable size and the installation must be in
accordance with the Canadian Electrical Code,
C22.1-02.
WARNING:
California Proposition 65 lists chemical
substances known to the state to cause
cancer, birth defects, death, serious illness
or other reproductive harm. This product
may contain such substances, be their
origin from fuel combustion (gas, oil) or
components of the product itself.

Installation
6 720 800 537 (2011/09)
9
4 Installation
4.1 Important information
Please follow these instructions. Failure to follow
instructions may result in:
•Damage or injury.
•Improper installation/operation.
•Loss of warranty.
4.1.1 Freeze prevention
Introduction
Please note that the installation manual states that the
water heater must not be installed in a location where it
may be exposed to freezing temperatures. If the heater
must be left in a space that is likely to experience
freezing temperatures, all water must be drained from
the heater.
Freeze damage is not covered under the warranty.
Draining the heater
Due to the shape of the heat exchangers and connecting
pipe, it is extremely difficult to get all of the water out of
the heater. Follow the procedure below to best minimize
the chance of freezing:
BDisconnect electric supply.
BDisconnect cold and hot water pipes from fittings on
bottom of heater. Allow water to drain out (have a
catch basin ready).
BAfter allowing all water to drain out, the heater should
be blown out with low pressure compressed air to
remove as much water as possible from water heater
modules. Bursts of air work better than continuous
flow.
Remember, these suggestions are only made to help
minimize the potential for freeze damage and are not to
be construed as the guaranteed method for dealing with
freeze possibilities.
4.2 Installing the AE 3.4/7.2/9.5
To operate correctly the unit needs the following
running pressures:
Sink
•Min: 10 psi (0,7 bar)
•Max: 150 psi (10,3 bar)
DANGER: Risk of electric shock!
BFor safety reasons, disconnect the power
supply to the heater before any service or
testing is performed.
WARNING:
BThis heater must be electrically grounded
in accordance with the most recent
edition of the National Electrical Code.
NFPA 70. In Canada, all electrical wiring
to the heater must be in accordance with
local codes and the Canadian Electrical
Code, CSA C22.1 Part 1.
DANGER:
BThe installation must only be performed
by a qualified person in accordance with
these instructions.
BBosch Thermotechnology Corp. is not
responsible for improperly installed
appliances.
WARNING:
BThe heater must only be wall mounted
and positioned with the water
connections located either at bottom or
the right side of the unit see Fig. 6. Under
no circumstances should the heater be
mounted differently.
WARNING:
BELECTRICITY IS EXTREMELY
DANGEROUS. TAKE EXTRA
PRECAUTIONS AND ENSURE ALL
CIRCUIT BREAKERS ARE OFF BEFORE
PERFORMING ANY WORK TO THE
HEATER.
Use of agents like anti-freeze are not
allowed as they may cause damage to the
water heater’s internal components.
WARNING:
BDo not install the AE 3.4/7.2/9.5 in a
room where there is a chance of freezing.
NOTE:
BRead entire instructions.
BCheck the pressure of the main water
supply.

Installation
6 720 800 537 (2011/09)
10
4.3 Water connections
BThe unit should be connected directly to the main
cold water supply and not to pre- heated water. The
unit should be installed with service valves on both
the inlet and outlet. These valves can be used to turn
off the water supply to the unit if it needs servicing, or
to reduce the water flow if it is too high.
BWe recommend that you use ½" copper or high
pressure flex connections.
BUse Teflon tape for sealing pipe threads. Do NOT use
pipe dope.
BRemember to keep the hot water pipe runs as short
as possible. In some cases it may be worth fitting a
second unit to serve an additional fixture.
BThe inlet and outlet are clearly marked on the unit.
They each have a ½" NPT connector.
BIf the unit is to supply a sink, we recommend that you
use aerators, which you can get from your local
distributor/dealer.
BIf the unit is to supply more than one sink, the aerator
should be the same at each tap if they are to be used
at the same time. If not, one outlet will take all the
water.
BAfter the unit has been plumbed in, and before you
wire it, flush it with water to remove any debris or
loose particles. Failure to do so may make the unit
inoperable.
4.3.1 Water quality
Water quality can have an impact on appliance longevity
and may not be covered under the manufacturer's
warranty.
BFor water analysis data call your local water
department, or if on a well, have well water analyzed
periodically.
If water quality exceeds one or more of the values
specified below, Bosch recommends consulting a
local water treatment professional for water
softening/conditioning options.
4.4 Electrical connections
Connecting the unit to power
BStrip back the insulation on the power wires about
3/8". Any insulation on the ground should be stripped
back about 3/4".
BFeed the cable through the cover bottom or backplate
rear entry grommets, as appropriate.
As a condition of installing this product in
the Commonwealth of Massachusetts a
pressure relief valve must be installed on
the cold water side by a licensed plumber.
MGL 42 Section 19.
Approval number: P1-09-25
Description Max. Levels
pH pH 6.5 - 8.5
TDS (total Dissolved
Solids)
mg/l or ppm 500
Total hardness mg/l or ppm 100
Aluminum mg/l or ppm 2.0
Chlorides mg/l or ppm 250
Copper mg/l or ppm 1.0
Iron mg/l or ppm 0.3
Manganese mg/l or ppm 0.05
Zinc mg/l or ppm 5.0
Table 5
WARNING:
BThe unit must be installed by a qualified
electrician.
BThe unit must be grounded.
BConnect the unit to power.
Model
Rated
Voltage
(V)
Rated
Current
(A)
Recommen
d Wire Size
(AWG)
US3 110 30 10
US7 240 30 10
US9 208 35 8
US9 240 40 8
Table 6
NOTE:
When the AE 3.4/7.2/9.5 is not within sight
of the electrical circuit breakers, a circuit
breaker lockout or additional local means of
disconnection for all non grounded
conductors must be provided that is within
sight of the appliance. (REF NEC 422.31)