Bosch T4200 14-2D Guide

Installation and Users Instructions
Gas Instantaneous Water Heater
Therm 4200
T4200 11/14/18-2D
6 720 821 605 (2017/08) ZA

2
Table of contents
Therm 4200 – 6 720 821 605 (2017/08)
Table of contents
1 Key to symbols and safety instructions . . . . . . . 3
1.1 Key to symbols . . . . . . . . . . . .. . . . . . . . . . . .. . . . 3
1.2 Safety information . . . . . . . . . . . .. . . . . . . . . . . . . 3
2 Technical Characteristics and Dimensions . . . . 6
2.1 Type overview . . . . . . . . . . . . .. . . . . . . . . . . .. . . . 6
2.2 Material attached . . . . . . . . . .. . . . . . . . . . . .. . . . 6
2.3 Type plate . . . . . . . . . . . . .. . . . . . . . . . . .. . . . . . . 6
2.4 Description of appliance . . . . . . . . . . .. . . . . . . . . . 6
2.5 Accessory (not supplied with the appliance) . . . . 6
2.6 Dimensions . . . . . . . . .. . . . . . . . . . . .. . . . . . . . . . 7
2.7 Electrical diagram . . . . . . . . . .. . . . . . . . . . . .. . . . 8
2.8 Function . . . . . . . . . . . . . . .. . . . . . . . . . . .. . . . . . . 8
2.9 Technical Data . . .. . . . . . . . . . . . .. . . . . . . . . . . . . 9
3Use. . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . .. . . 10
3.1 Digital display - description . . . . . . . .. . . . . . . . . 10
3.2 Batteries . . . . . . . . . . . . . .. . . . . . . . . . . .. . . . . . 10
3.3 Before starting up the heater . . . . . . . . . . . . .. . . 10
3.4 Turning the heater on and off .. . . . . . . . . . . .. . . 10
3.5 Water flow . . . . . . . . . .. . . . . . . . . . . .. . . . . . . . . 11
3.6 Power adjustment . . . . . . . . . . . . .. . . . . . . . . . . . 11
3.7 Temperature/flow adjustment . . . . . . . . .. . . . . . 11
4Regulations. . . . . . . . . . .. . . . . . . . . . . .. . . . . . 11
5 Installation (must be carried out only by 
qualified technicians) . . . . . . . . . . . . . . . . . .. . . 12
5.1 Important information . . . . . . . . . . . . . . .. . . . . . 12
5.2 Selection of location for installation . . . . . . . . . . 12
5.3 Fixing the appliance . . . . . . . . . . .. . . . . . . . . . . . 13
5.4 Water connection . . . . . . .. . . . . . . . . . . .. . . . . . 13
5.5 Hydrogenerator operation . . . . . . . . . . . .. . . . . . 14
5.6 Gas connection . . . . . . . . . . . .. . . . . . . . . . . .. . . 14
5.7 Commissioning . . . . . . . . . . . . . . .. . . . . . . . . . . . 14
6 Adjustments (must be carried out only by . . . .. .
qualified technicians) . . . . . . . . . . . . .. . . . . . . . . . . .. . . 15
6.1 Factory regulations . . . . . .. . . . . . . . . . . .. . . . . . 15
6.2 Pressure regulation . . . . . . . . . . . . . . . . . .. . . . . . 15
6.3 Conversion to a different type of gas . . . . . . . . . . 16
7 Maintenance (must be carried out only by . . . . . .
qualified technicians) . . . . . . . . . .. . . . . . . . .. . . . . . . . . 16
7.1 Periodic maintenance tasks . . . . . . . . . . . . . . .. . 16
7.2 Startup after maintenance work . . . . . . . . . . . . . 16
7.3 Heater purge . . . . . . . . . . . . . .. . . . . . . . . . . . .. . 16
7.4 Flue gas safety device . . . . . . .. . . . . . . . . . . . .. . 17
7.5 Safe operation/ risk for prolonged use . . . . . . . . 17
8Problems. . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . 18
8.1 Problem/cause/solution . .. . . . . . . . . . . . .. . . . . 18
9 Environment / disposal . . . . . . . . . . . . . .. . . . . 19
10 Warranty Terms . . . . . . . . . .. . . . . . . . . . . . .. . 19

3
Key to symbols and safety instructions
Therm 4200 – 6 720 821 605 (2017/08)
1 Key to symbols and safety instructions
1.1 Key to symbols
Warnings
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
ifmeasurestopreventtheriskarenottaken.
The following keywords are defined and can be used in this
document:
•NOTICEindicatesasituationthatcouldresultindamageto
property or equipment.
•CAUTIONindicatesa situationthat could result in minorto
medium injury.
•WARNING indicates a situation that could result in severe
injury or death.
•DANGER indicates a situation that willresult in severe
injury or death.
Important information
Thissymbolindicatesimportantinformation
where there is no risk to people or property.
Additional symbols
Table 1
Symbol Explanation
▶Step in an action sequence
Cross-reference to another part of the document
•List entry
–List entry (second level)
1.2 Safety information
Important
▶ Read these instructionsfor use
carefully so as to familiarize yourself
with the appliance before connecting
it to its gas container.
▶ Keep these instructions for future
reference.
If there is a smell of gas:
▶ Close the gas valve.
▶ Open windows.
▶ Do not connect any electrical
appliance.
▶ Extinguish any naked flames.
▶ 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.
Fitting, modifications
▶ The fitting and modification of the
installation of the appliance must be
carried out only by an authorized
technician.
▶ The 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.
▶ The pipes carrying burnt gases must
not be modified.
▶ Do not close or reduce air circulation
holes.

4
Key to symbols and safety instructions
Therm 4200 – 6 720 821 605 (2017/08)
Maintenance
▶ The user must maintain and
periodically service the appliance.
▶ The user is responsible for the safety
and environmental compatibility of
the installation.
▶ The appliance should be serviced
annually.
▶ Only original spare parts should 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).
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
shouldonlysignforacceptanceofthe
installation when the installation is
completed to your satisfaction.Note
that your invoice is required in the
eventthatyouwishmakeaguarantee
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.

5
Key to symbols and safety instructions
Therm 4200 – 6 720 821 605 (2017/08)
Safety of electrical appliances for
domestic use and similar purposes
The following requirements apply in
accordancewithEN60335-1inorderto
prevent hazards from occurring when
using electrical appliances:
“This appliance can be used by children
of8yearsandolder,aswellasbypeople
with reduced physical, sensory or
mental capabilities or lacking in
experience and knowledge, if they are
supervised and have been given
instruction in the safe use of the
appliance and understand the resulting
dangers.Childrenmustnotplaywiththe
appliance. Cleaning and user
maintenance must not be performed by
children without supervision.”
“If the power cable is damaged, it must
be replaced by the manufacturer, its
customer service department or a
similarly qualified person, so that risks
are avoided.”

6
Technical Characteristics and Dimensions
Therm 4200 – 6 720 821 605 (2017/08)
2 Technical Characteristics and
Dimensions
2.1 Type overview
Table 2
T4200 11 -2 D23
31
T4200 14 -2 D23
31
T4200 18 -2 D23
31
[T] Gas instantaneous water heater
[4200] Series
[11] Capacity (l/min)
[-2] Version
[D] Digital display
[23] Appliance set for natural gas
[31] Appliance set for LPG
2.2 Material attached
•Gaswaterheater
• Fixing elements
• Connections elements
• Documentation
• Two 1.5 V batteries type R
2.3 Type plate
Thetypeplateislocatedontheleft side of the appliance, on the
bottom.
It contains details of the output of the appliance, the order
number, the approvaldata and the date of manufacture in
encoded form (FD).
2.4 Description of appliance
Operating convenience, as the heater is ready to operate by
simply pressing a switch.
• Heater for wall-mounting
• Ignitionbyelectronicdevicetriggeredwhenthewatervalve
opens
• Gauge to display temperature, burner operation and
malfunctions
• Temperature sensor to monitor the water temperature at
the heater output
• 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 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 foraccidental extinction of
the burner flame
– Fluegassafetydevicewhichturnsofftheheaterincase
of inadequate combusted gas evacuation conditions
– Temperaturelimiterwhichpreventsoverheatingof the
heat exchanger
2.5 Accessory (not supplied with the appliance)
• Conversion kit from natural gas to butane/propane and
vice-versa.

7
Technical Characteristics and Dimensions
Therm 4200 – 6 720 821 605 (2017/08)
2.6 Dimensions
Fig. 1
[4] Heat exchanger
[5] Burner
[10] Temperature/volume selector
[20] Gas connection
[23] Ignition unit
[24] Battery compartment
[26] Power selector
[34] LED - Burner status check
[35] Switch / LED - Battery status check
[36] Front cover
[37] Hole for fixing to wall
[38] Exhaust pipe union
[39] Flue with non-return device
[40] Gas valve
[42] Digital display
Table 3 Dimensions
Dimensions (mm) A B C D E F G H (Ø)
Natural gas LPG
T4200 11-2D... 310 580 228 112,5 463 60 25 1/2”
T4200 14-2D... 350 655 228 125 510 95 30 1/2”
T4200 18-2D... 425 655 334 125 540 65 30 1/2”

8
Technical Characteristics and Dimensions
Therm 4200 – 6 720 821 605 (2017/08)
2.7 Electrical diagram
Fig. 2 Electrical diagram
[2] Spark plug
[3] Ionisation probe
[15] Micro-switch
[23] Ignition unit
[24] Battery compartment
[25] Servo valve (normally open)
[28] Gas valve (normally closed)
[31] Temperature limiter
[32] Flue gas safety device
[33] Diaphragm valve
[34] LED - Burner status check
[35] Switch / LED - Battery status check
[41] Temperature sensor
[42] Digital display
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. 6).
Afterthis procedure,automatic ignition occurswhenever 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.
Air in the gas supply pipe when the heater is
started up may cause ignition to fail.
If this happens:
▶ Close and open the hot water tap to repeat the ignition
process until all the air has been purged.

9
Technical Characteristics and Dimensions
Therm 4200 – 6 720 821 605 (2017/08)
2.9 Technical Data
Table 4
Technical Data Symbol Units T4200 11-2D T4200 14-2D T4200 18-2D
Output and heat demand
Rated max. heat output Pn kW
(Btu/h) 19,2 (65570) 23,6 (80595) 30,5 (104165)
Rated min. heat output Pmin kW
(Btu/h) 7,0
(23905) 9,0 (30710) 9,3 (31733)
Output (modulation range) kW
(Btu/h) 7 - 19,2 (23905-65570) 9,0 - 23,6 (30710-80595) 9,3 - 30,5 (31733-104165)
Rated max. heat input Qn kW
(Btu/h) 21,8
(74450) 27,0 (92210) 34,5 (117825)
Rated min. heat input Qmin kW
(Btu/h) 9,5 (32415) 10,4 (35486) 10,8 (36851)
Gas supply specifications1)
1) Hi 15 °C - 1013 mbar - dry: Natural gas 34.2 MJ/m3(9.5 kWh/m3) 
LPG: Butane 45.72 MJ/kg (12.7 kWh/kg) - Propane 46.44 MJ/kg (12.9 kWh/kg)
Supply pressure
Natural gas H G20 kPa 2,0 2,0 2,0
LPG (butane/propane) G30/G31 kPa 2,8 2,8 2,8
Consumption
Natural gas H G20 m3/h 2,2 2,77 3,5
LPG (butane/propane) G30/G31 kg/h 1,75 2,2 2,79
Number of injectors 12 14 18
Water system specifications
Max. water pressure2)
2) Considering the water dilution effect this value must not be exceeded
pw MPa 1,2 1,2 1,2
Temperature control at maximum setting
Temperature increase °C 50 50 50
Flow range l/min 2 - 5,5 2 - 7 2 - 8,8
Min. operating pressure pwmin MPa 0,01 0,01 0,02
Minimum pressure for maximum flow MPa 0,025 0,035 0,05
Temperature control at minimum setting
Temperature increase °C 25 25 25
Flow range l/min 4 - 11 4 - 14 4 - 17,6
Min. operating pressure MPa 0,02 0,02 0,02
Minimum pressure for maximum flow MPa 0,06 0,1 0,13
Flue specifications3)
3) For nominal calorific power
Draught requirement MPa 0,0015 0,0015 0,0015
Flow rate g/s 13 17 22
Temperature °C 160 170 180

10
Use
Therm 4200 – 6 720 821 605 (2017/08)
3Use
Open all water and gas blocking devices. 
Purge the pipes.
CAUTION: The area in front of the burner
canreachveryhightemperatures,andthere
is a risk of burning on contact.
3.1 Digital display - description
Fig. 3 Digital display
[1] Temperature/error code
[2] Malfunction indicator
[3] Temperature measurement units
[4] Heater in operation (burner turned on)
3.2 Batteries
Battery insertion
▶ Insert 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 Before starting up the heater
CAUTION:
▶ The initial startup of the heater must be
realized by a qualified technician, who
will provide the client with all the
information necessary for its correct
usage.
▶ Check if the gas indicated on the type plate is the same as
the one used at the location.
▶ Open the gas valve.
▶ Open the water valve.
3.4 Turning the heater on and off
Turning on
▶ Press the switch , position .
Fig. 6
Green light on = Main burner on

11
Regulations
Therm 4200 – 6 720 821 605 (2017/08)
Fig. 7
Turning off
▶Presstheswitch , position .
3.5 Water flow
If the red LED starts flashing, check the water pressure.
Fig. 8
3.6 Power adjustment
Lower water temperature.
Less power.
Fig. 9
Higher water temperature.
More power.
Fig. 10
3.7 Temperature/flow adjustment
▶Turnanti-clockwise
Increases flow and decreases water temperature.
Fig. 11
▶Turnclockwise.
Decreases flow and increases water temperature.
Regulating the temperature to the minimum required value
reduces energy consumption as well as the possibility of lime
scale deposits in the heat exchanger.
CAUTION:Thetemperatureonthedisplayis
not precise, always check before bathing
children or elderly people.
4Regulations
Any local by-laws and regulationspertaining toinstallationand
useofgas-heatedappliancesmustbeobserved.Pleasereferto
the laws that should be attended in your country.

12
Installation (must be carried out only by qualified technicians)
Therm 4200 – 6 720 821 605 (2017/08)
5 Installation (must be carried out only by
qualified technicians)
DANGER: Explosion!
▶ Always turn off the gas cock before 
carrying out any work on components
which carry gas.
The appliance must be installed in
accordance with the requirements of SANS
10087-1forusewithLPG,SANS827foruse
with NG and any fire department regulations
and/or local bylaws applicable to the area.
Installation, electrical connection, gas
installation, connection of inlet and exhaust
pipes and initial startup must be realized
exclusively by authorized personnel.
The appliance can only be sold in the
countries mentioned in the type plate.
NOTICE: Damage to the device!
Leaking connections.
▶ Do not put the device down on the floor
with the connections facing
downwards, so that the metal threads
are not damaged.
5.1 Important information
▶ Before installation, consult the gas company and current
legislation regarding gas appliance and site ventilation.
▶ Install a gas shut-off tap as close to the appliance as
possible.
▶ After connection to the gas main, the appliance should be
carefully cleaned and tested for leaks; to avoid damage
fromexcesspressureinthevalvegasregulator,thisshould
be carried out with the gas valve shut.
▶ Ensure that the appliance installed is suitable for the type
of gas provided.
▶ Ensure that the flow and pressures for the regulator
installed are those indicated for the consumption of the
appliance (see technical data in table 4).
Water quality
The device is used for DHW heating for domestic purposes in
accordance with the relevant regulations. Use of a water
treatment system is recommended in areas with a high level of
waterhardness.Thewaterparameters,whichhaveaneffecton
limescale, must generally comply with the values given in
Tab. 5.
Table 5
TDS (Total dissolved solids) (mg/l) Hardness
(mg/l) pH
0 - 600 0 - 180 6,5 - 9,0
NOTICE: Damage to the device!
Ifthesevaluesarenotobserved,itcanresultin
partial blockage and faster ageing of the
internal body of the device.
5.2 Selection of location for installation
Considerations relevant to location
• Donotinstalltheappliance in roomswherethefreevolume
is less than 8 m3.
• Fulfil requirements specific to each country.
•Theappliancemustnotbeinstalled in sites where the
ambient temperature is susceptible to drop below 0 °C.
Wherethereisa riskoffreezing,disconnectandempty the
appliance.
• The gas heater must not be installed over a heat source.
• To avoid corrosion, products such as solvents, inks,
inflammablegases,glue or domestic detergents containing
halogenic hydro-carbons or any product that might
provoke corrosion must not be stored near the air
admission grill.
• Respecttheminimuminstallationmeasurementsindicated
in Fig. 12.
• The heater must not be installed in locations where the
room temperature can reach 0 °C.
In case of a frost risk:
▶Turntheheateroff.
▶ Remove batteries.
▶Purgetheheater(section 7.3).

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
13
Installation (must be carried out only by qualified technicians)
Therm 4200 – 6 720 821 605 (2017/08)
Fig. 12 Minimum clearances (in cm)
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
• A flexible or rigid pipe should be used, fit it inside the flue
socket.Theexternaldiameterofthepipeshouldbeslightly
smaller than the dimension specified in the appliances
dimensions table.
• The extremity of the evacuation pipe must be protected
against wind/rain
CAUTION: Ensure that the extremity of the
evacuationpipeisplacedbetween the ledge
and the ring of the flue.
Where these conditions are not possible to achieve, an
alternative location must be selected.
Flue ducts
If the flue duct goes through walls and/or furniture containing
flammable material:
▶ Thermalinsulatetheducttoensurethatthetemperatureof
the contact surface is less than 85 °C.
Surface temperature
The maximum surface temperature of the appliance is below
85 °C. Special protection measures are not required for
inflammable building materials or housings.
Air admission
The place where the heater is to be installed must havean area
of air supply according to the table.
Table 6 Useful areas for air admission
Appliance Minimum area
T4200 11-2D 60 cm2
T4200 14-2D 90 cm2
T4200 18-2D 120 cm2
Minimum requirements are listed above. Local regulations
should always be observed.
5.3 Fixing the appliance
▶ Remove the temperature/flow selector and the power
selector.
▶ Unscrew the cover fixing screws.
▶ Remove the outer case by sliding it forwards and then
lifting upwards.
▶ Fix the appliance using the sleeves and hooks supplied so
that it is vertical.
CAUTION:Neverallowtheappliancetorest
against water or gas pipes.
5.4 Water connection
It is advisable to drain the appliance before installing it as any
dirt or grit inside it could reduce the water flow rate and, in
extreme cases, could completely clog up the appliance.
▶ Mark cold water [A] and hot water pipes [B], so as to
prevent confusion.
▶ Connect pipe to water valve using the connecting kit
supplied.
Fig. 13 Water connection

Itis advisableto install a non-returnvalveon
the supply side of the heater to avoid
problems caused by sudden changes in
supply pressure.
14
Installation (must be carried out only by qualified technicians)
Therm 4200 – 6 720 821 605 (2017/08)
5.5 Hydrogenerator operation
The hydrogenerator (hydrodynamic generator) is inserted in
the water circuit between the water valve and the heat
exchanger. This component has a turbine that rotates when
waterflowspastitsblades.Thismovementistransmittedtoan
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
DANGER:
Non-compliance with legal standards
applicable may cause a fire or explosion,
causing material damage or personal injury
or even death.
Only use original accessories.
Thegasconnectiontothewaterheatermustabsolutelycomply
with the National Standards.
▶ First ensure that the water heater to be installed
corresponds to the type of gas supplied.
▶ Fit a gas shut-off valve at theentrance as close as possible
to the appliance.
▶ After completion of the gas network. thorough cleaning
must be done and a tightness test carried out to avoid
damage due to excess pressure in the gas system, this has
tobe carriedoutwith thegasvalve of the applianceclosed.
▶ Check that the flow and the pressure supplied for the
reducer installed are those indicated for the consumption
of the appliance (see technical data in tab. 4).
Installation with flexible tube (G.P.L.)
DANGER: Dangerto lifecausedby gas leak!
▶ Proceed to replace the tube if you find
that it is dry and fragile.
▶ Replace the tube at least every four
years.
Theinstallation,if done withflexibletube(not metal),onlyfor
appliances designed to be connected to a bottle of Butane,
must comply with the following:
• must have a possible minimum length of at most 1.5 m;
• the tube must comply with ET IPQ 107-1 and applicable
standards;
• must be controllable all the waythrough;
• must not come near areas where heat is released;
• avoid folds or other bottlenecks;
• the connection at the ends must be made with proper
accessories and tabs without grooves
▶ Check that the supply tube is clean.
▶ Use the accessory door rubbers (supplied) and a tab to
make the connection to the incoming gas of the appliance.
Installation with connection to a gas supply network
▶ Inthecaseofaninstallationwithconnectiontoagassupply
network, you must use metal tubes in accordance with the
applicable standards.
To make the connection between the gas supply network and
the water heater, you must use the accessory supplied.:
▶ Tighten the coil in the incoming gas tube.
▶ Usetheendincoppertodotheweldingtothetubefromthe
supply network
Gas pressure regulator
Thisappliance requiresanoperatingpressureof2,8kPa at the
appliance. A suitable LPG regulator that complies with the
requirements of SANS 1237 must be installed.
Any local by-laws andregulations pertainingto installationand
use of gas-heated appliances must be observed.
Please refer to the laws that should be attended in your
country.
5.7 Commissioning
▶ Turn on the gas and water cocks and check all connections
for leaks.
▶ Insert the two batteries correctly (Fig. 4) 1.5V type R
supplied with the heater.
▶ Check flue gas safety device is functioning correctly,
proceed as explained in section 7.4.

15
Adjustments (must be carried outonly by qualified technicians)
Therm 4200 – 6 720 821 605 (2017/08)
6 Adjustments(mustbecarriedoutonlyby
qualified technicians)
6.1 Factory regulations
Sealed parts must not be interfered with.
Natural gas
Heaters must not be turned on if the
connectionpressureislowerthan1,5kPaor
higher than 2,5 kPa.
Heaters for natural gas (G 20) are supplied sealed from the
factory afterbeingadjustedto the valuesindicatedon thetype
plate.
Liquefied gas
The appliances must not be operated if the
dynamic connection pressure is:
- Propane: less than 2,5 kPa or greater than
4,5 kPa
-Butane: less than 2,0 kPa or greater than
3,5 kPa.
Heatersfor propane/butane (G31/G30) are supplied sealed
fromthefactoryafter beingadjustedtothevaluesindicatedon
the type plate.
DANGER: The following procedures must
only be performed by a qualified technician.
Powermaybetunedaccordingtotheburnerpressureprocess,
for which a manometer is required.
6.2 Pressure regulation
Access to the adjuster screw
▶ Remove the appliance front cover (see section 5.3).
Connection of manometer
▶ Loosen the shutter screw.
▶ Connect the manometer to theburnerpressure measuring
point.
6720607418-01.3V
Fig. 14 Pressure measurement point
Maximum gas flow adjustment
▶ Remove the seal from the adjusting screw (Fig. 15).
▶ Turn on the heater with the power selector set to the left
(maximum position).
6720607418-02.2V
Fig. 15 Maximum gas flow adjusting screw
▶ Open several hot water taps.
▶ Using the adjusting screw (Fig. 15), regulate the pressure
until achieving the valuesindicated in the table7.
▶ Seal the adjusting screw once again.
Minimum gas flow adjustment
The minimum gas flow adjustment is
performed automatically after the
adjustment of the maximum gas flow.

Table 7 Burner pressure
Natural
gas H Butane Propane
Injector code 11 8708202113
(110) 8 708 202 130
(70)
8708202124
(120) 8708202128 (72)
14 8 708 202 113
(110) 8708202128
(72)
8708202116
(125) 8708202132 (75)
18 8708202115
(115) 8708202130
(70)
8708202116
(125) 8708202132 (75)
Connection
pressure (kPa) 11
14
18
2,0 2,8 3,7
Burner pressure 
MAX (kPa) 11 1,27 2,8 3,5
14 1,2 2,8 3,5
18 1,03 2,55 3,25
16
Maintenance (must be carried out only by qualified technicians)
Therm 4200 – 6 720 821 605 (2017/08)
6.3 Conversionto 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.
7 Maintenance (must be carried out only
by qualified technicians)
The appliance should only be serviced by an
approved engineer. A complete overhaul
should be carried out after two years.
WARNING:
Before performing any maintenance work:
▶ Close the water flow valve.
▶ Close the gas flow valve.
▶ Use only authentic spare parts and accessories.
▶ Order the spare parts according to the spare parts
catalogue for the heater.
▶ Replace dismantled joints and o-rings with new ones.
▶ Only the following lubricants must be used:
– On hydraulic parts: Unisilikon L 641 (8 709 918 413)
– Threaded joints: HFt 1 v 5 (8 709 918 010).
7.1 Periodic maintenance tasks
Functional checks
▶ Ensure that all safety, regulatory and checking elements
are in good working order.
Heat exchanger
▶ Check if 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.
▶ Ifnecessary:De-limetheinterioroftheheatexchangerand
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.
WARNING: Without a water filter installed,
turning on the heater is prohibited.
7.2 Startup after maintenance work
▶ Tighten all connections once more.
▶Readchapter3 “Use” and chapter 6 “Adjustments”.
7.3 Heater purge
In case of a frost risk, proceed as follows:
▶ Remove the retaining clip from threaded bushing [1].
▶ Remove threaded bushing [2] from water valve.

17
Maintenance (must be carried out only by qualified technicians)
Therm 4200 – 6 720 821 605 (2017/08)
▶ Empty the appliance of all water.
Fig. 16 Purging
[1] Retaining clip
[2] Threaded bushing
7.4 Flue gas safety device
DANGER: The probe must never be turned
off, modified or replaced with a different
part under any circumstances.
Operation and precautions
This probe verifies the conditions of flue evacuation and, in
case of malfunction, it automatically turns off the heater.This
prevents the combustion gases from entering the room where
the gas heater has been installed. The probe restarts after a
reset period.
If the heater turns off during operation:
▶ Ventilate the room.
▶ 10 minutes later, turn on the heater once again.
Call a qualified technicianif the same thing happens again.
DANGER: The user must never touch the
device.
Maintenance1)
If the probe malfunctions, proceed in the following manner:
▶ Unscrew the probe fixing screw.
▶ Detach the ignition unit terminal.
▶ Replace the damaged part and proceed with its assembly
using the steps indicated in the previous table, in reverse
order.
Operating check1)
To check the correct operation of the combustion gas probe,
proceed in the following manner:
▶ Remove the combustion gases evacuation pipe.
▶ Replace it with a pipe (approximately 50 cm long) blocked
at one end.
▶ The pipe must be routed vertically.
▶ Turn on the heater at nominal power and with the
temperature selector adjusted to maximum temperature.
In these conditions, the heater must turn off two minutes
afterwards, at most. Remove the pipe and replace the
evacuation pipe.
7.5 Safe operation/ risk for prolonged use
Prolongedusepower wearsomeelementsmaycausegasleaks
and transhipment of products of combustion.
Preventively should:
▶ Makeavisualinspectionofthemaintenanceintervalstothe
following elements:
–Gasvalve
–Combustionchamber
In case of corrosion visible:
▶ Call the intervention of a qualified contractor.
1) These procedures must be performed bya qualified
installer.

18
Problems
Therm 4200 – 6 720 821 605 (2017/08)
8Problems
8.1 Problem/cause/solution
Assembly, maintenance and repairs must be performed by
qualifiedtechnicianonly.Thefollowingchartofferssolutionsto possible problems (solutions followed by an * must be undertaken by qualified technician only).
Problem Cause Solution
The heater does not ignite and
digital display is turned off.
Slow and difficult ignition of the
burner. 
Red LED in switch flashes.
Batteries flat, not inserted correctly or
switch turned off. 

Flat batteries. 

Flat batteries.
▶ Check battery position and/or replace them,
check switch position.
▶ Replace them.
▶ 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 (digital display shows “E9”).

Monitoring device of combustion
gases evacuation has tripped (digital
display shows “A4”).
▶ Wait 10 minutes and restart the heater.
If the problem persists, call a qualified
technician.
▶ Ventthearea.Wait 10 minutesand restartthe
heater.
If the problem persists, call a qualified
technician.
Incorrect temperature information
in the appliance digital display. Insufficientcontactofthetemperature sensor. ▶ Check and correct the temperature sensor assembling.
Digital display shows “E1”. Water temperature sensor has tripped
(outlet water temperature above
85 °C).
▶ Reduce the water temperature using the
power and/or temperature adjustment
selector.
If the problem persists, call a qualified
technician.
Digital display shows “A7”. Temperature sensor incorrectly
connected.
Temperature sensor defective.
▶ Check and correct connection.
▶ Replace the temperature sensor.
Blocked heater. Digital display shows “F7” or “E0”. ▶ Turn the heater off and on.
If the problem persists, call a qualified
technician.
Thereis spark but the main burner
does not ignite, heater blocked. No ionisation probe signal (digital display shows “EA”). Check:
•Gassupply.
• Ignition system (ionisation electrode and
electrovalves)
Table 8

19
Environment / disposal
Therm 4200 – 6 720 821 605 (2017/08)
9 Environment / disposal
Environmental protection is a fundamental corporate strategy
of the Bosch Group. 
Thequalityofour products,theirefficiencyandenvironmental
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 ourpackaging materials areenvironmentallyfriendlyand
can be recycled.
Used appliances
Used appliances contain valuable materials that should be
recycled.
Thevarious assembliescan beeasily dismantledand synthetic
materialsaremarkedaccordingly.Assembliescanthereforebe
sorted by composition and passedon for recycling or disposal.
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;
• Whentheoperation anduseoftheappliance is doneunder
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.
Blocked heater, digital display
shows “F0”. Supply (switch or battery replacement) was activated with a hot
water tap running.
▶ Turn the heater off and on.
If the problem persists, call a qualified
technician.
Burn-back Downdraft (strong winds).
Burner defect.
GAs quality.
▶ Call a qualified technician.
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.*
Problem Cause Solution
Table 8