Bosch WR 11 G Series Technical Document

Installation Manual and Operating Instructions
Gas Instantaneous Water Heater
WR 11/14/18 .G...
6 720 607 529 (2016/04) 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!

6 720 607 529 (2016/04)
2 | Table of contents
Table of contents
1 Key to symbols and safety instructions . . . . . . . . . . 3
1.1 Key to symbols . . . . . . . . . . . . . . . . . . . . . . . 3
1.2 Safety Instructions . . . . . . . . . . . . . . . . . . . . 3
2 Technical Characteristics and Dimensions . . . . . . . 5
2.1 Explanation of Model Code . . . . . . . . . . . . . . 5
2.2 Accessories (Included with appliance) . . . . 5
2.3 Description of the heater . . . . . . . . . . . . . . . 5
2.4 Type overview . . . . . . . . . . . . . . . . . . . . . . . . 5
2.5 Special accessories . . . . . . . . . . . . . . . . . . . . 5
2.6 Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.7 Electrical diagram . . . . . . . . . . . . . . . . . . . . . 7
2.8 Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.9 Technical characteristics . . . . . . . . . . . . . . . 8
3 Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.1 Before starting up the heater . . . . . . . . . . . . 9
3.2 Turning the heater on and off . . . . . . . . . . . . 9
3.3 Water flow . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.4 Power adjustment . . . . . . . . . . . . . . . . . . . . 10
3.5 Temperature/flow adjustment . . . . . . . . . . 10
3.6 Purge the appliance . . . . . . . . . . . . . . . . . . 10
3.7 Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4 Regulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
5 Installation (must be carried out only by qualified
technicians) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5.1 Important information . . . . . . . . . . . . . . . . . 11
5.2 Selection of the place of installation . . . . . 11
5.3 Heater mounting . . . . . . . . . . . . . . . . . . . . . 12
5.4 Water connection . . . . . . . . . . . . . . . . . . . . 12
5.5 Hydrogenerator operation . . . . . . . . . . . . . 12
5.6 Gas connection . . . . . . . . . . . . . . . . . . . . . . 13
5.7 Inlet/exhaust pipe installation . . . . . . . . . . 13
5.8 Startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
6 Adjustments (must be carried out only by qualified
technicians) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
6.1 Factory regulations . . . . . . . . . . . . . . . . . . . 14
6.2 Pressure adjustment . . . . . . . . . . . . . . . . . . 14
6.3 Conversion to a different type of gas . . . . . 15
7 Maintenance (must be carried out only by qualified
technicians) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
7.1 Periodic maintenance work . . . . . . . . . . . . 16
7.2 Startup after maintenance work . . . . . . . . 16
7.3 Flue gas safety device . . . . . . . . . . . . . . . . . 16
8 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
9 Environment / disposal . . . . . . . . . . . . . . . . . . . . . . . 18
10 Warranty Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

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Key to symbols and safety instructions | 3
1 Key to symbols and safety instructions
1.1 Key to symbols
Warnings
The following keywords are defined and can be used in this
document:
•NOTICE indicates a situation that could resultin damage to
property or equipment.
•CAUTION indicates a situation that could result in minor to
medium injury.
•WARNING indicates a situation that could result in severe
injury or death.
•DANGER indicates a situation that will result in severe
injury or death.
Important information
Additional symbols
1.2 Safety Instructions
If there is a smell of gas:
▶ Close the gas valve.
▶ Open windows.
▶ Do not operate any electrical appliances or switches (on/
off).
▶Extinguishanynakedflames.
▶ Phone the gas company or an authorized technician from a
safe distance.
If there is a smell of burnt gases:
▶ Disconnect the appliance.
▶ Open doors and windows.
▶ Inform an installation company.
Burn-back (fire in burner tube or chamber)
▶ In 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.
▶ After ensuring the flame is extinguished, wait for one
minute and re-light the appliance in the normal manner.
▶ Should the appliance again burn back, close the control
valve and call a service technician.
▶ Do not use the appliance again until the service technician
has declared that it is safe to do so.
Fitting, modifications
▶ The fitting and modification of the installation of the
appliance must be carried out only by an authorized
technician.
▶ The installation ofthe water heater may only be carried out
by a registered installer and that such installations shall
comply with the requirements of SANS 10087-1.
▶ The pipes carrying burnt gases must not be modified.
▶ Do not close or reduce air circulation holes.
Maintenance
▶ We reccomend to have the system regularly serviced in
order to ensure that it functions reliably and safely.
▶ The installer is responsible for the safety and
environmental compatibility of the installation.
▶ The appliance should be serviced annually.
▶ Only original spare parts must be used.
Explosive and inflammable materials
▶ Inflammable materials (paper, solvents, ink, etc.) should
not be stored near the appliance.
Combustion air and ambient air
▶ To avoid corrosion, combustion air and ambient air should
be free of aggressive substances (for example halogenated
hydrocarbons containing chlorine and fluoride
composites).
Warnings in this document are identified by
a warning triangle printed against a grey
background.
Keywords at the start of a warning indicate
the type and seriousness of the ensuing risk
if measures to prevent the risk are not taken.
This symbol indicates important information
where there is no risk to people or property.
Symbol Explanation
▶ Step in an action sequence
Cross-reference to another part of the document
• List entry
– List entry (second level)
Table 1

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4 | Key to symbols and safety instructions
Important information for the user
▶ This appliance may only be installed by a registered LP Gas
installer.
▶ All registered installers are issued with a card carrying their
registration number.
▶ Ask 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 foracceptance
of the installation when the installation is completed to your
satisfaction.Note that your invoice is required in the event
that you wish make a guarantee claim.
Important information for the installer
▶ This appliance may only be installed by a LP gas installer
registered with the Liquefied Petroleum Gas Association of
Southern Africa.
▶ The 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.
▶ Upon 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
▶ Inform the client about the function and operation of the
appliance.
▶ Caution clients against performing modifications or repairs
themselves.
Risk of damage due to operator error
Operator errors can result in personal injury and material
damage.
▶ Ensure that children never operate this appliance
unsupervised or play with it.
▶ Ensure that only personnel who can operate this appliance
correctly have access to it.

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Technical Characteristics and Dimensions | 5
2 Technical Characteristics and Dimensions
2.1 Explanation of Model Code
[W] Gas Water Heater
[R] Proportional power adjustment
[11] Capacity (l/min)
[G] Electronic ignition powered by hydrodynamic generator
[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:
2.2 Accessories (Included with appliance)
•Gaswaterheater,
• Attachment elements,
• Installation accessories,
• Heater documentation.
2.3 Description of the heater
Operating convenience, as the heater is ready to operate by
simply pressing a switch.
• Heater for wall-mounting,
• Ignitionbyelectronicdevice triggeredwhenthewatervalve
opens,
• Great savings in comparison with conventional heaters,
due to the possibility of power adjustment and no
permanent pilot flame,
• Hydrodynamic generator produces the necessary
electrical power for ignition and appliance monitoring,
• 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 safetydevice which turns off the heater in case
of inadequate combusted gas evacuation conditions,
– Temperature limiter which prevents overheating of the
heat exchanger.
2.4 Type overview
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.
2.5 Special accessories
• Conversion kit from natural gas to butane/propane.
WR11 G 23
31
S....
WR14 G 23
31
S....
WR18 G 23
31
S....
Table 2
Identification
Code
Wobbe Index (Ws)
(15 °C)
Gas type
23 12,7-15,2 kWh/m3Natural Gas - Group H
31 20,2-21,3 kWh/m3LPG - Group B/P
Table 3

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6 | Technical Characteristics and Dimensions
2.6 Dimensions
Fig. 1
[1] Front cover
[2] Hole for fixing to wall
[3] Observation window
[4] Temperature control
[5] Led failure indicator
[6] ON/OFF switch
[7] Led indicator for burner status
[8] Output control
[9] Gas connection
[10] Flue socket
[11] Draught diverter with flue gas monitor
[12] Heat exchanger
[13] Automatic gas valve
[14] Igniter unit
[15] Water valve
Dimensions (mm) A B C D E F G H (Ø)
Natural
gas
LPG
WR11G 310 580 228 112,5 463 60 25 1/2” 1/2”
WR14G 350 655 228 132,5 510 95 30 1/2” 1/2”
WR18G 425 655 334 132,5 540 65 30 1/2” 1/2”
Table 4 Dimensions

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Technical Characteristics and Dimensions | 7
2.7 Electrical diagram
Fig. 2 Electrical diagram
[1] Servo valve (normally open)
[2] Diaphragm valve
[3] Main valve (normally closed)
[4] Ionisation detector
[5] Igniter electrode
[6] Flue gas safety device
[7] Temperature limiter
[8] Igniter unit
[9] LED failure indicator
[10] LED indicator for burner status
[11] ON/OFF switch
[12] Hydrogenerator
2.8 Function
This gas heater is equipped with automatic electronic ignition
which simplifies its operation.
▶ To do so, just turn on the switch (Fig. 3).
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:
▶ Close 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.

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8 | Technical Characteristics and Dimensions
2.9 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 5,0 5,0 6,5
Temperature selector in fully anti-clockwise position
Temperature rise °C 25 25 25
Flow range l/min 4 - 11 4 - 14 4 - 17,6
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 5

6 720 607 529 (2016/04)
Use | 9
3Use
3.1 Before starting up the heater
▶ Check if the gas indicated on the rating plate is the same as
the one used at the location.
▶ Open the gas valve.
▶ Open the water valve.
3.2 Turning the heater on and off
Turning on
▶ Press the switch , position .
Fig. 3
Green light on = Main burner on
Fig. 4
Turning off
▶ Press the switch , position .
3.3 Water flow
If the red LED starts flashing, check the water pressure.
Fig. 5
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:
▶ Initial 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.
6720680412-02.1av
6720680412-03.1av
6720607845-01.1V

6 720 607 529 (2016/04)
10 | Regulation
3.4 Power adjustment
Lower water temperature.
Less power.
Fig. 6
Higher water temperature.
More power.
Fig. 7
3.5 Temperature/flow adjustment
▶ Turn anti-clockwise
Increases flow and decreases water temperature.
Fig. 8
▶Turnclockwise.
Decreases flow and increases water temperature.
Regulating the temperature to the minimum required value
reduces energy consumption as well as the possibility of
limescale deposits in the heat exchanger.
3.6 Purge the appliance
If there is a risk of freezing, proceed as follows:
▶ Remove the retaining clip from threaded bushing [1].
▶ Remove threaded bushing [2] from water valve.
▶ Empty the appliance of all water.
Fig. 9 Purge
[1] Retaining clip
[2] Threaded bushing
3.7 Cleaning
▶ Clean the front cover using a damp cloth and detergent.
4Regulation
Any local by-laws and regulations pertaining to installation and
use of gas-heated appliances must be observed. Please refer to
the laws that should be attended in South Africa.
Do not use abrasive or corrosive cleaners.
6720617434-02.1Av
2
1

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Installation (must be carried out only by qualified technicians) | 11
5 Installation (must be carried out only by
qualified technicians)
5.1 Important information
▶ Before installing, call the gas company and check the
standard relating to gas heaters and ventilation
requirements for rooms.
▶ Install a gas cut-off valve as close as possible to the heater.
▶ After finishing the gas system, the pipes must be
thoroughly cleaned and leak-tested; to avoid damaging the
gas valve by excess pressure, this test must be performed
with the gas valve of the heater closed.
▶ Check if the heater corresponds to the type of gas
provided.
▶ Check if the flow and pressure through the installed
reducer are appropriate for the consumption of the heater
(see technical data in the table 3).
5.2 Selection of the place of installation
Requirements regarding the place of installation
• Do not install the heater in rooms with a volume of less than
8 m3(not including the volume of the furniture providing
this does not exceed 2 m3.
• Comply with the specific instructions for each country.
• Assemble the gas heater in a well-ventilated location where
it will not be exposed to temperatures below zero and in a
place where there is an evacuation pipe for combustion
gases.
• The gas heater must not be installed over a heat source.
• To avoid corrosion, the combustion air must be free from
harmful substances. Examples of particularly corrosive
substances: halogenated hydrocarbons contained in
solvents, paints, glues, engine gases and various domestic
detergents. If necessary, take adequate measures.
• Respect the minimum installation clearances indicated in
Fig. 10.
• The heater must not be installed in locations where the
room temperature can reach 0 °C.
In case of a frost risk:
▶ Turn off the heater,
▶Purgetheheater(section 3.6).
Fig. 10 Minimum clearances
The appliance must be installed in accordance
with the requirements of SANS 10087-1 for use
with LPG, SANS 827 for use with NG and any
fire department regulations and/or local bylaws
applicable to the area.
DANGER: Explosion!
▶ Always turn off the gas cock before
carrying out any work on components
which carry gas.
Installation, electrical connection, gas
installation, connection of inlet and exhaust
pipes and initial 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.
The appliance can only be sold in the countries
mentioned in the type plate.
The use of these heaters with water supply
pressures values below 7.25 psi is not
recommended.
L(m) h(cm)
0-1 3
1-2 6
2-3 9
3-4 24
6720607539-02.6Av
³30
3
h
L
³180
33
40
³100
£140

6 720 607 529 (2016/04)
12 | Installation (must be carried out only by qualified technicians)
Combustion gases
• All gas heaters must be connected in a leak-roof manner to
a gas evacuation pipe of adequate dimensions.
•Thefluemust:
– be vertical (reduced horizontal sections or no
horizontal sections at all)
– be thermally insulated
– have an exit above the maximum roof level.
• The combustion gases evacuation pipe must be inserted in
the flue ring. The external diameter of the pipe must be
slightly less than the diameter of the flue indicated in the
table of heater dimensions.
• The extremity of the evacuation pipe must be protected
against wind/rain.
If these conditions cannot be met, a different location must be
selected for the gas intake and evacuation.
Surface temperature
The maximum surface temperature of the heater is less than
85 °C, with the exception of the combustion gases evacuation
device. No special protection measures are required for
flammable construction materials or built-in furniture items.
Air intake
The place where the heater is to be installed must have an area
of air supply according to the table.
The minimum requirements are listed above; however, each
country's specified requirements must also be respected.
5.3 Heater mounting
▶ Remove the temperature/flow selector and the power
selector.
▶ Unscrew the front fixing screws.
▶ With a simultaneous movement towards you and upwards,
release the front of the two lugs from the back.
▶ Fix the heater vertically, using the provided screw hooks
and plugs.
5.4 Water connection
It is advisable to purge the installation beforehand, because the
presence of dirt may reduce the flow and, in extreme cases,
cause a blockage.
▶ Identify the cold water pipe [A] and the hotwater pipe [B],
so as to avoid any possible mis-connection.
▶ Connect the water pipes to the water valve using the
provided connection accessories.
Fig. 11 Water connection
5.5 Hydrogenerator operation
The hydrogenerator (hydrodynamic generator) is inserted in
the water circuit between the water valve and the heat
DANGER:
Make sure that all flue connections are tighten
sealed.
▶ Failure to follow this requirement may
cause dangerous exhaust gases to enter
living space which may result causing
personal injury or loss of life.
CAUTION:
Ensure that the extremity of the evacuation
pipe is placed between the ledge and the ring
of the flue.
Heater Minimum useful area
WR11G 60 cm2
WR14G 90 cm2
WR18G 120 cm2
Table 6 Useful areas for air intake
CAUTION:
Never support the gas heater on the water or
gas connections.
It is advisable to install a non-return valve on the
supply side of the heater to avoid problems
caused by sudden changes in supply pressure.

6 720 607 529 (2016/04)
Installation (must be carried out only by qualified technicians) | 13
exchanger. This component has a turbine that rotates when
water flows past its blades. This movement is transmitted to an
electric generator which powers the heater ignition unit.
The electrical voltage value supplied by the HDG is between
1,7VRMS and 2,2 VRMS AC. In this way, there is no need for
batteries.
5.6 Gas connection
Gas pressure regulator
This appliance requires an operating pressure of 2,8 kPa at the
appliance. A suitable LPG regulator that complies with the
requirements of SANS 1237 must be installed.
Any local by-laws and regulations pertaining to installation and
use of gas-heated appliances must be observed.
Please refer to the laws that should be attended in your
country.
5.7 Inlet/exhaust pipe installation
Pipes should be installed according to the instructions in the
relevant manual.
▶ Once connected, the pipe should be inspected and the seal
guaranteed.
5.8 Startup
▶Openthewaterandgasflowvalves and check that all
connections are leak-tight.
▶ Check the flue gas safety device is functioning correctly,
proceed as explained in “Section 7.3 Combustion gas
probe”.
DANGER:
If local regulations are not follow exactly, a fire
or explosion may result causing property
damage, personal injury or loss of life.
Only use accessories recommended in this
manual.
DANGER: Make sure that all flue connections
are tighten sealed.
▶ Failure to follow this requirement may
cause dangerous exhaust gases to enter
living space which may result causing
personal injury or loss of life.

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14 | Adjustments (must be carried out only by qualified technicians)
6 Adjustments (must be carriedout only by
qualified technicians)
6.1 Factory regulations
Natural gas
Heaters designed for Natural gas H (G 20) are factory sealed for
delivery after the values on the characteristics panel have been
checked.
Liquid gas
Propane/butane heaters (G31/G30) are factory sealed for
delivery after the values on the characteristics panel have been
checked.
Power may be tuned according to the burner pressure process,
for which a manometer with U-shaped connecting tubes is
required.
6.2 Pressure adjustment
Accessing the adjusting screw
▶ Remove the front part of the heater (section 5.3).
Connecting the pressure gauge
▶Unscrewtheshut-offscrew.
▶ Connect the pressure gauge to the measuring point for the
burner pressure.
Fig. 12 Pressure measurement points
Maximum gas flow adjustment
▶ Remove the screw seal (Fig. 13).
▶ Turn on the heater with the power selector set to the left
(maximum position).
Fig. 13 Maximum gas flow adjusting screw
▶ Open various hot water taps.
▶ Using the adjusting screw, regulate the pressure until
obtaining the values indicated in the table 7.
▶ Seal the adjusting screw once again.
Minimum gas flow adjustment
Sealed parts must not be interfered with.
Heaters should not be ignited when the
connections pressure is less than 1,7 kPa more
than 2,5 kPa.
Heaters should not be ignited when the
connections pressure is:
- Propane: less than 2,5 kPa more than 4,5 kPa.
- Butane: less than 2,0 mbar more than 3,5 kPa.
The minimum gas flow adjustment is performed
automatically after the adjustment of the
maximum gas flow.
6720607418-01.3V
6720607418-02.2V

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Adjustments (must be carried out only by qualified technicians) | 15
6.3 Conversion to a different type of gas
Only use the original conversion kits.
The conversion must only be performed by a qualified
technician. The original conversion kits are supplied with
assembly instructions.
Natural gas H Butane Propane
Injector code
WR11
8708202113
(1,10)
8708202130
(0,70)
8708202124
(1,20)
8708202128
(0,72)
WR14
8708202113
(1,10)
8708202128
(0,72)
8708202116
(1,25)
8708202132
(0,75)
WR18
8708202115
(1,15)
8708202130
(0,70)
8708202116
(1,25)
8708202132
(0,75)
Connection
pressure
(psi)
WR11
WR14
WR18
233
MAX (psi)
WR11 1,27 2,8 3,5
WR14 1,2 2,8 3,5
WR18 1,03 2,55 3,25
Table 7 Burner pressure

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16 | Maintenance (must be carried out only by qualified technicians)
7 Maintenance (must be carried out only by qualified technicians)
To ensure that gas consumption and the environmental load
(pollution, etc.) remain as negligible as possible over a longer
period of time, we recommend that you assure to have the
appliance maintained on an annual basis (inspection) or if
necessary (maintenance).
These jobs can only be done by a Bosch Technical Assistance
delegate.
▶ Only use original spare parts.
▶ Order the spare parts according to the spare parts
catalogue for the heater.
▶ Replace the joints and removed O-rings with new ones.
▶ Only the following lubricants must be used:
– Hydraulic part: Unisilikon L 641 (8 709 918 413)
– Threaded joints: HFt 1 v 5 (8 709 918 010).
7.1 Periodic maintenance work
Functional check
▶ Check the operation of all safety, adjustment and
monitoring elements.
Heat exchanger
▶ Check the heat exchanger is clean.
▶Incaseofdirt:
– Remove the heat exchanger and take out the limiter.
– Clean the chamber with a powerful jet of water.
▶ If dirt persists: Soak the plates in hot water with detergent
and clean thoroughly.
▶ If necessary: De-lime the interior of the heat exchanger and
the connection pipes.
▶ Install the heat exchanger using new joints.
▶ Install the limiter on the support.
Burner
▶ Check the burner annually and clean it if necessary.
▶ If it is very dirty (grease, soot): Remove the burner, soak it
in hot water with detergent and clean it thoroughly.
Water filter
▶ Replace the water filter installed in the water valve entry.
Burner and pilot injector
▶ Remove and clean the pilot burner.
▶ Remove and clean the pilot injector.
7.2 Startup after maintenance work
▶ Tighten all connections once more.
▶ Read chapter 3 “Use” and chapter 6 “Adjustments”.
7.3 Flue gas safety device
Operation and safety precautions
The flue gas safety device checks the effectiveness of flue gas
extraction by the flue. If it is inadequate, the appliance switches
off automatically so that the combustion fumes do not escape
into the room in which the appliance has been installed. The
flue gas safety device resets after a cooling-down period.
If the appliance shuts down while in operation:
▶ Ventilate the room.
▶ Wait about 10 minutes then restart the appliance.
If the problem recurs, call an engineer.
Maintenance
If faults occur on the flue gas safety device, proceed as follows:
▶ Undo flue gas safety device fixing screw.
▶ Loosen temperature limiters connectors.
▶ Undo magnetic unit connector.
▶ Remove thermocouple.
▶ Replace damaged component with new one and refit using
the reverse of the procedure set out in the table above.
DANGER:
Explosion!
▶ Always turn off the gas cock before
carrying out any work on components
which carry gas.
CAUTION: Leaking water may damage the
appliance!
▶ Always empty the system before
disassembly of any hydraulic system part.
WARNING:
Is forbidden to start up the appliance without
water filter correctly assembled.
DANGER:
The flue gas safety device must not under any
circumstances be switched off, simulated or
replaced by any other component.
DANGER:
The user must never make any modifications
to the flue gas safety device.

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Problems | 17
Function check
Flue gas safety device function check:
▶ Disconnect flue pipe;
▶ Replace with pipe (about 50 cm long) with sealed end;
▶ Fit pipe vertically;
▶ Start up appliance at rated output and set temperature
control to maximum temperature;
Under those conditions, the appliance should shut down
after two minutes. Remove temporary pipe and reconnect
flue pipe.
8Problems
Assembly, maintenance and repairs must be performed by qualified technicians only. The following chart offers solutions to
possible problems (solutions followed by an * must be undertaken by qualified technicians only).
Problem Cause Solution
The heater does not ignite.
Slow and difficult ignition of the
burner.
Red LED flashes.
Switch turned off.
Reduced water flow.
Reduced water flow.
▶ Check switch position.
▶ Check and correct.
▶ Check and correct.
Water at low temperature. ▶ Check the temperature selector position
and adjust it according to the desired water
temperature.
Water is not heated, no flame. Insufficient gas supply. ▶ Check reducer, and if inadequate or
malfunctioning, replace it.
▶ Check if the bottles (butane) freeze during
operation, and if so, move them to a warmer
place.
The burner turns off the heater is
operating.
Temperature limiter has tripped.
Flue gas safety device has tripped.
▶ Wait 10 minutes and restart the heater. If
the problem persists, call a qualified
technician.
▶ Vent the area. Wait 10 minutes and restart
the heater. If the problem persists, call a
qualified technician.
There is spark but the main burner
does not ignite.
No ionisation probe signal. Check:
•Gassupply,
• Ignition system (ionisation electrode and
electrovalves).
Reduced water flow. Insufficient water supply pressure.
Dirty taps or mixers.
Gas valve blocked.
Heat exchanger blocked (limescale).
▶ Check and correct. *
▶ Check and clean.
▶ Clean filter.*
▶ Clean and de-lime if necessary.*
Table 8

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18 | Environment / disposal
9 Environment / disposal
Environmental protection is a fundamental corporate strategy
of the Bosch Group.
The quality of our products, their efficiency and environmental
safety are all of equal importance to us and all environmental
protection legislation and regulations are strictly observed.
We use the best possible technology and materials for
protecting the environment taking into account of economic
considerations.
Packaging
We participate in the recycling programmes of the countries in
which our products are sold to ensure optimum recycling.
All of our packaging materials are environmentally friendly and
can be recycled.
Used appliances
Used appliances contain valuable materials that should be
recycled.
The various assemblies can be easily dismantled and synthetic
materials are marked accordingly. Assemblies can therefore be
sorted by composition and passed on for recycling or disposal.

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Warranty Terms | 19
10 Warranty Terms
Imported by:
Bosch Thermotechnology South Africa
Robert Bosch PTY (Ltd)
15th Road, Randjiespark
1685 Midrand
South Africa
Tel: [phone]
Bosch Gas Water Heaters have been thoroughly tested at the
factory and fulfills all standards valid in the country. Robert
Bosch (Pty) Ltd. provides warranty for this model and its
components, for the period of 24 months from the date of the
invoice, for any factory or material fault, with the following
exceptions:
• When the installation of the product was done by
unauthorized people;
• When the appliance or parts present changes or
malfunctions due to misuse of unauthorized people;
• When the operation and use of the appliance is done under
conditions which are not allowed in the installation or
user's manual;
• When there are changes to the warranty terms and
breakage of seals;
• When damages are caused by transportation or accidents;
• When damages are caused by inadequate gas or water
pressure;
• When damages are caused by lack of maintenance or by
installing non-original parts;
Robert Bosch (Pty) Ltd. does not take over any responsibility
for personal damage, property damage or product damage
caused by installations done by unauthorized persons.
Therefore, we highly recommend that the installation is done
by a certified gas installer.

6720607529