Bosch WR11B series Technical Document

Installation Manual and Operating Instructions
Gas Instantaneous Water Heater
WR 11/14/18 .B..
6 720 648 592 (2011/06) ZA
Read installation manual prior to installation of this unit!
Read user manual before putting this unit in operation!
Observe the warnings in the manuals!
The installation room must fulfill the ventilation requirements!
Installation by an authorised person only!

2| Table of contents
6 720 648 592 (2011/06)
Table of contents
1 Key to symbols and safety instructions 3
1.1 Explanation of symbols 3
1.2 Safety Instructions 3
2 Technical Characteristics and Dimensions 5
2.1 Declaration of conformity with relevant EEC
regulations 5
2.2 Explanation of Model Code 5
2.3 Accessories (Included with Appliance) 5
2.4 Description of the heater 5
2.5 Explanation of model code 5
2.6 Special accessories 6
2.7 Dimensions 6
2.8 Functional diagram of the heater 7
2.9 Electrical diagram 8
2.10 Function 8
2.11 Technical characteristics 9
3Use 10
3.1 Before starting up the heater 10
3.2 Batteries 10
3.3 Turning the heater on and off 10
3.4 Power adjustment 11
3.5 Temperature/flow adjustment 11
3.6 Purge the appliance 11
3.7 Cleaning 11
4Regulation 12
5 Installation (must be carried out only by
qualified technicians) 13
5.1 Important information 13
5.2 Selection of the place of installation 13
5.3 Heater mounting 14
5.4 Water connection 14
5.5 Gas connection 14
5.6 Inlet/exhaust pipe installation 15
5.7 Startup 15
6 Adjustments (must be carried out only by
qualified technicians) 16
6.1 Factory regulations 16
6.2 Pressure adjustment 16
6.3 Conversion to a different type of gas 17
7 Maintenance (must be carried out only by
qualified technicians) 18
7.1 Periodic maintenance work 18
7.2 Startup after maintenance work 18
7.3 Flue gas safety device 18
8Problems 20
9 Environment / disposal 21

Key to symbols and safety instructions | 3
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1 Key to symbols and safety instructions
1.1 Explanation of symbols
Warnings
Keywords indicate the seriousness of the hazard in
terms of the consequences of not following the safety
instructions.
•NOTE indicates that material damage may occur.
•CAUTION indicates that minor to medium injury may
occur.
•WARNING indicates that serious injury may occur.
•DANGER indicates possible risk to life.
Important information
Additional symbols
1.2 Safety Instructions
If there is a smell of gas:
BClose the gas valve.
BOpen windows.
BDo not operate any electrical appliances or switches
(on/off).
BExtinguish any naked flames.
BPhone the gas company or an authorized technician
from a safe distance.
If there is a smell of burnt gases:
BDisconnect the appliance.
BOpen doors and windows.
BInform an installation company.
Burn-back (fire in burner tube or chamber)
BIn the event of a burn-back, where the flame burns
back to the injector, immediately turn off the gas
supply at the control valve on the panel.
BAfter ensuring the flame is extinguished, wait for one
minute and re-light the appliance in the normal
manner.
BShould the appliance again burn back, close the
control valve and call a service technician.
BDo not use the appliance again until the service
technician has declared that it is safe to do so.
Fitting, modifications
BThe fitting and modification of the installation of the
appliance must be carried out only by an authorized
technician.
BThe installation of the water heater may only be
carried out by a registered installer and that such
installations shall comply with the requirements of
SANS 10087-1.
BThe pipes carrying burnt gases must not be modified.
BDo not close or reduce air circulation holes.
Maintenance
BWe reccomend to have the system regularly serviced
in order to ensure that it functions reliably and safely.
BThe installer is responsible for the safety and
environmental compatibility of the installation.
BThe appliance should be serviced annually.
BOnly original spare parts must be used.
Warnings in this document are framed and
identified by a warning triangle which is
printed on a grey background.
Electrical hazards are identified by a
lightning symbol surrounded by a warning
triangle.
Important information in cases where there
is no risk of injury or material losses is
identified by the symbol shown on the left.
It is bordered by horizontal lines above and
below the text.
Symbol Meaning
Ba step in an action sequence
Æa reference to a related part in the
document or to other related documents
•alistentry
– a list entry (second level)
Table 1

4| Key to symbols and safety instructions
6 720 648 592 (2011/06)
Explosive and inflammable materials
BInflammable materials (paper, solvents, ink, etc.)
should not be stored near the appliance.
Combustion air and ambient air
BTo avoid corrosion, combustion air and ambient air
should be free of aggressive substances (for example
halogenated hydrocarbons containing chlorine and
fluoride composites).
Important information for the user
BThis appliance may only be installed by a registered
LP Gas installer.
BAll registered installers are issued with a card carrying
their registration number.
BAsk to be shown the card before allowing the
installation work to commence and make a note of the
Installer QCC number. Upon completion of the
installation, the installer is required to explain the
operational details of the appliance together with the
safety instructions. You will be asked to sign
acceptance of the installation and be provided with a
completion certificate. You should only sign for
acceptance of the installation when the installation is
completed to your satisfaction.
BNote that your invoice is required in the event that you
wish make a guarantee claim.
Important information for the installer
BThis appliance may only be installed by a LP gas
installer registered with the Liquefied Petroleum Gas
Association of Southern Africa.
BThe appliance must be installed in accordance with
the requirements of SANS 10087-1 and any fire
department regulations and/or local by laws
applicable to the area. If in doubt check with the
relevant authority before undertaking the installation.
BUpon completion of the installation you are required
to fully explain and demonstrate to the user the
operational details and safety practices applicable to
the appliance and the installation.
Client information
BInform the client about the function and operation of
the appliance.
BCaution clients against performing modifications or
repairs themselves.
Risk of damage due to operator error
Operator errors can result in injury and damage to
property.
BEnsure that children never operate this appliance
unsupervised or play with it.
BEnsure that only personnel who can operate this
appliance correctly have access to it.

Technical Characteristics and Dimensions | 5
6 720 648 592 (2011/06)
2 Technical Characteristics and Dimensions
2.1 Declaration of conformity with
relevant EEC regulations
This appliance fulfills European directive requirements
2009/142/EC, 2006/95/EC, 2004/108/EC and
corresponds to the specifications described in the
corresponding EEC certificate of proof.
2.2 Explanation of Model Code
WGas Water Heater
RProportional power adjustment
11 Capacity (l/min)
BElectronic ignition powered by 1.5 V batteries
23 Indicator number of natural gas H
31 Indicator number of LPG
S... Country code
The code number indicates the gas group according to
EN 437:
2.3 Accessories (Included with Appliance)
•Gaswaterheater,
• Attachment elements,
• Installation accessories,
• Two 1.5 V batteries type R
•Heaterdocumentation.
2.4 Description of the heater
Operating convenience, as the heater is ready to operate
by simply pressing a switch.
• Heater for wall-mounting,
• Ignition by electronic device triggered when the water
valve opens,
• Great savings in comparison with conventional
heaters, due to the possibility of power adjustment
and no permanent pilot flame,
• Natural gas/LPG burner,
• Semi-permanent pilot burner which only functions
during the period between the opening of the water
valve and the ignition of the main burner,
• Heat exchanger in copper without tin/lead covering,
• Water valve in fibreglass-reinforced polyamide, 100%
recyclable,
• Automatic adjustment of the water flow by means of
a device which permits a constant flow to be
maintained in spite of variable pressure supplies,
• Gas flow adjustment proportional to the water flow to
maintain a constant high temperature.
•Safetydevices:
– Ionisation probe to check for accidental extinction
of the burner flame,
– Flue gas safety device which turns off the heater in
case of inadequate combusted gas evacuation
conditions,
– Temperature limiter which prevents overheating of
the heat exchanger.
2.5 Explanation of model code
The type plate is located at the bottom left of the
appliance.
There you will find details of appliance output, model
number, approval data and the serial number.
Model WR 11/14/18 B...
Category II2H3+
Type Type B
Table 2
WR11 B 23
31
S....
WR14 B 23
31
S....
WR18 B 23
31
S....
Table 3
Identification
Code
Wobbe Index
(Ws) (15 °C) Gas type
23 12,7-15,2
kWh/m3
Natural Gas -
Group H
31 20,2-21,3
kWh/m3LPG - Group B/P
Table 4

6| Technical Characteristics and Dimensions
6 720 648 592 (2011/06)
2.6 Special accessories
• Conversion kit from natural gas to butane/propane.
2.7 Dimensions
Fig. 1
1Front cover
2Hole for fixing to wall
3Temperature control
4Led indicator for battery charge level
5ON/OFF switch
6Led indicator for burner status
7Output control
8Gas connection
9Flue socket
10 Draught diverter with flue gas monitor
11 Heat exchanger
12 Automatic gas valve
13 Igniter unit
14 Battery compartment
Dimensions
(mm) A B C D E F G
H (Ø)
Natural
gas LPG
WR11B 310 580 228 112,5 463 60 25 1/2” 1/2”
WR14B 350 655 228 132,5 510 95 30 1/2” 1/2”
WR18B 425 655 334 132,5 540 65 30 1/2” 1/2”
Table 5 Dimensions

Technical Characteristics and Dimensions | 7
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2.8 Functional diagram of the heater
Fig. 2 Functional diagram
1Pilot burner
2Igniter electrode
3Ionisation detector
4Heat exchanger
5Main burner
6Injector
7a Testing point for burner pressure
7b Testing point for supply pressure
8Venturi
9Temperature/volume selector
10 Water valve
11 Adjusting screw for min. water flow rate
12 Water flow regulator
13 Water filter
14 Cold water supply pipe
15 Diaphragm
16 Microswitch
17 Main gas valve
18 Regulating screw
19 Gas inlet
20 Gas filter
21 Battery compartment
22 Hot water pipe
23 Igniter unit
24 Led indicator for burner status
25 ON/OFF switch
26 Led indicator for battery charge level
27 Servo valve
28 Output control
29 Gas valve
30 Gas valve for pilot burner
31 Pilot burner injector
32 Gas pipe for pilot burner
33 Temperature limiter
34 Flue gas safety device

8| Technical Characteristics and Dimensions
6 720 648 592 (2011/06)
2.9 Electrical diagram
Fig. 3 Electrical diagram
1Servo valve (normally open)
2Diaphragm valve
3Main valve (normally closed)
4Ionisation detector
5Igniter electrode
6Flue gas safety device
7Temperature limiter
8Igniter unit
9LED indicator for battery charge level
10 LED indicator for burner status
11 ON/OFF switch
12 Batteries, 1.5V
13 Microswitch
2.10 Function
This gas heater is equipped with automatic electronic
ignition which simplifies its operation.
BTo do so, just turn on the switch (ÆFig. 6).
After this procedure, automatic ignition occurs
whenever a hot water tap is opened. First, the pilot
burner is lit and approximately four seconds afterwards
the main burner. The pilot burner flame is then
extinguished after a short period of time.
This is a way of saving a great amount of energy as the
pilot burner only operates for the minimum necessary
time to ignite the main burner, in contrast to
conventional systems which operate permanently.
If this happens:
BClose and open the hot water tap to repeat the
ignition process until all the air has been purged.
Air in the gas supply pipe when the heater is
started up may cause ignition to fail.

Technical Characteristics and Dimensions | 9
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2.11 Technical characteristics
Technical characteristics Symbol Units WR11 WR14 WR18
Power and flow
Nominal useful power Pn Btu/h 65570 80595 104165
Minimum useful power Pmin Btu/h 23905 23905 23905
Useful power (adjustment range) Btu/h 23905-65570 23905 - 80595 23905 - 104165
Nominal thermal flow Qn Btu/h 74450 92210 117825
Minimum thermal flow Qmin Btu/h 27660 27660 27660
Gas data1)
1) Hi 15 °C - 1013 mbar - dry: Natural gas 34.02 MJ/m3(9.5 kWh/m3)
LPG: Butane 45.65 MJ/kg (12.7 kWh/kg) - Propane 46.34 MJ/kg (12.9 kWh/kg)
Supply pressure
Natural gas H G20 kPa 2 22
LPG (Butane/Propane) G30 kPa 2,8 2,8 2,8
Consumption
Natural gas H G20 m3/h 2,2 2,77 3,5
LPG (Butane/Propane) G30 Kg/h 1,75 2,2 2,79
Number of injectors 12 14 18
Water data
Maximum permissible pressure2)
2) Considering the water dilution effect this value must not be exceeded.
pw psi 170 170 170
Temperature selector in fully clockwise position
Temperature rise °C 50 50 50
Flow range l/min 2 - 5,5 2,0 - 7 2,0 - 8,8
Minimum operating pressure pwmin psi 1,5 1,5 3,0
Minimum pressure for maximum water
flow psi 3,6 5,0 7,2
Temperature selector in fully anti-clockwise position
Temperature rise °C 25 25 25
Flow range l/min 4 - 11 4 - 14 4 - 17,6
Minimum pressure for maximum water
flow psi 8,7 14,5 19
Combustion products3)
3) For nominal calorific power.
Minimum low pressure mbar 0,015 0,015 0,015
Flow g/s 13 17 22
Temperature °C 160 170 180
Table 6

10 | Use
6 720 648 592 (2011/06)
3Use
3.1 Before starting up the heater
BCheck if the gas indicated on the rating plate is the
same as the one used at the location.
BOpen the gas valve.
BOpen the water valve.
3.2 Batteries
Battery insertion
BInsert the two 1.5 V R20 batteries.
Fig. 4 Inserting the batteries
Replacing the batteries
The batteries must be changed if the red LED starts
flashing.
Fig. 5 Replacing the batteries
Precautions when using the batteries
• Do not dispose of batteries as domestic waste. Take
them to appropriate collecting places for recycling.
• Do not insert flat batteries.
• Only use the type of batteries indicated.
3.3 Turning the heater on and off
Turning on
BPress the switch , position .
Fig. 6
Green light on = Main burner on
Fig. 7
Open all water and gas blocking devices.
Purge the pipes.
CAUTION:
The front panel in the burner and pilot
burner area may reach high temperatures,
with risk of burning in case of contact
CAUTION:
BInitial startup must be performed by a
qualified technician who will provide the
client with all the necessary information
for optimum operation of the gas heater.
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