Room sealed gas continuous flow water heaters
6720808879-00.1V
OptiFlow Professional
GWH12/16/20 1 CTD E23/31 F5 L
Operating Manual
Read installation manual prior to installation of this appliance!
Read user manual before putting this unit in operation!
Observe the warnings in the manuals!
The installation location must meet the requirements for sufficient ventilation!
Installation by an authorised person only!
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2 | Index
Index
1 Key to symbols and safety instructions . . . . . . . . . . 3
1.1 Key to symbols . . . . . . . . . . . . . . . . . . . . . . . 3
1.2 Safety Information . . . . . . . . . . . . . . . . . . . . . 3
2 Product details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1 EC Declaration of Conformity . . . . . . . . . . . . 4
2.2 Type overview . . . . . . . . . . . . . . . . . . . . . . . . 4
2.3 Included Items . . . . . . . . . . . . . . . . . . . . . . . . 5
2.4 Rating plate . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.5 Description of appliance . . . . . . . . . . . . . . . . 5
2.6 Accessory . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.7 Appliance layout . . . . . . . . . . . . . . . . . . . . . . 6
3 Operation instructions . . . . . . . . . . . . . . . . . . . . . . . . 7
3.1 Digital display - description . . . . . . . . . . . . . 7
3.2 Before first use of the appliance . . . . . . . . . . 7
3.3 Switching the appliance on/off . . . . . . . . . . . 7
3.4 Temperature control . . . . . . . . . . . . . . . . . . . 7
3.5 Programming button . . . . . . . . . . . . . . . . . . . 8
3.6 Draining the appliance . . . . . . . . . . . . . . . . . 8
3.7 Error codes . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.8 Cleaning the front of the appliance . . . . . . . 8
4Maintenance
(only by authorised service technicians) . . . . . . . . .8
5 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6 Environmental considerations . . . . . . . . . . . . . . . . . 11
7 Water quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
8 Warranty details . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
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Key to symbols and safety instructions | 3
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
if measures to prevent the risk are not taken.
The following keywords are defined and used in this document:
• NOTICE indicates a situation that could result in 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
This symbol indicates important information
where there is no risk to people or property.
Additional symbols
Symbol Explanation
▶ Step in an action sequence
Cross-reference to another part of the document
•List entry
– List entry (second level)
Table 1
1.2 Safety Information
If you smell gas
A gas leak could potentia lly cause an explosion. If you smell gas,
observe the following rules.
▶ Avoid producing flames or sparks:
– Do not smoke, do not use a lighter or strike matches.
– Do not operate any electrical switches or unplug any
equipment.
– Do not use the telephone or ring doorbells.
▶ Turn off the gas supply at the main shut-off valve or at the
gas meter.
▶ Open windows and doors.
▶ Warn your neighbours and leave the building.
▶ Prevent anyone from entering the building.
▶ Stay well away from the building: call the emergency
services and the gas supplier.
If you notice dark combustion gases or sooting:
▶ Isolate the gas supply to the heater.
▶ Notify an authorised technician.
Installation, assembly, and modifications
Installation, assembly, and modifications to the heater must
only be performed by an authorised technician.
Maintenance
▶ The water heater is required to have a service and safety
inspection every two years.
▶ The installer is responsible for the safety and
environmental compatibility of the installation.
▶ The owner/user is responsible for keeping the area around
the water heater free from debris.
▶ Safe access to inspect and service the water heater is the
responsibility of the property owner.
▶ Use only genuine Bosch spare parts.
Explosive and flammable material
▶ Do not store or use flammable material (paper, spray cans,
solvents, paints, etc) near the heater.
Combustion air and surrounding air
▶ The combustion air and surrounding air must be free from
corrosive substances.
▶ Do not spray aerosols or use chemicals around the heater
unless heater is disconnected from the power supply.
Risk of damage due to user error
User errors can result in injury and damage to property.
▶ Ensure that children never play with or operate this
appliance.
▶ Ensure that only personnel who can operate this appliance
correctly have access to it.
▶ Refer to the operating and user instructions before
adjusting the water heater.
To be installed and serviced only by an authorised person
The authorised installer is responsible for:
• Correct installation and commissioning of this appliance.
• Ensuring the appliance performs to the specifications
stated on the rating label.
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4 | Product details
• Demonstrating the operation of the appliance to the
customer before leaving.
• Handing these instructions to customer.
THIS APPLIANCE IS NOT SUITABLE FOR POOL OR SPA POOL
APPLICATIONS.
HANDING THE OPERATING INSTRUCTIONS TO THE
CUSTOMER.
NOT SUITABLE FOR COMMERCIAL BOOSTING OF A WARM
WATER RECIRCULATION SYSTEM
Regulations
All local by-laws and regulations pertaining to installation and
use of gas appliances must be observed.
This appliance must be installed in accordance with the
manufacturers installation instructions, AS/NZS5601, AS/
NZS3500, and all Local Building & Gas fitting regulations.
The appliance must not be installed outdoors. The appliance is
approved for indoor installation only. Do not install this
appliance with any modification or alteration.
Failure to install this appliance in accordance with these
installation instructions will void the warranty and may create
an unsafe situation.
Safety of electrical appliances for domestic use and similar
purposes
The following requirements apply in accordance with EN
60335-1 in order to prevent hazards from occurring when
using electrical appliances:
“This appliance can be used by children of 8 years and older, as
well as by people 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. Children
must not play with the 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.”
2 Product details
2.1 EC Declaration of Conformity
The appliance has been tested and certified to Australian
Standards.
Model GWH12/16/20 1 CTD E23/31 F5 L...
Table 2
2.2 Type overview
GWH 12 1CTDE23 F5 L
GWH 12 1CTDE31 F5 L
GWH 16 1CTDE23 F5 L
GWH 16 1CTDE31 F5 L
GWH 20 1CTDE23 F5 L
GWH 20 1CTDE31 F5 L
Table 3
[GWH]Gas continuous flow water heater
[12] Capacity (l/min)
[1] Generation
[CT] Thermostatic
[D] Digital user interface
[E] Electric ignition
[23] Appliance set for natural gas
[31] Appliance set for Universal LP gas
[F5] Tight chamber
[L] Locked water temperature adjustment
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2.3 Included Items
• Gas continuous flow water heater
• Fixing bracket
• Appliance documentation
2.4 Rating plate
The rating plate is located on the outside of the appliance, on
the bottom.
The rating plate specifies the performance of the appliance,
approval and serial numbers.
2.5 Description of appliance
• Room sealed wall-mounted appliance for internal
installation.
• Multifunctional display panel
• Suitable for Natural Gas or Universal LPG
• Electronic ignition
• Water flow sensor
•Water valve
• Temperature sensors for monitoring the temperatur e of the
incoming and outgoing water of the appliance.
•Safety devices:
–Flame sensor rod
–Thermal fuse
– Hot water temperature sensor
– Electronic control unit
– Air temperature sensor
• Electrical connection: 230 V, 50 Hz
• Frost protection device.
Product details | 5
2.6 Accessory
•Flue accessories
• Remote control (optional).
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6 | Product details
2.7 Appliance layout
Fig. 1
[1] Heat exchanger
[2] Flame sensor rod
[3] Burner
[4] Air pressure test point
[5] Fan
[6] Air temperature sensor
[7] Thermal fuse
[8] Hot water temperature sensor
[9] Hot water outlet
[10] Power cord and plug
[11] Combustion gas collector
[12] Frost protection device
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[13] Ignition electrode
[14] Burner pressure test point
[15] Water flow sensor and Water valve
[16] Electronic control unit
[17] Cold water temperature sensor
[18] Gas valve
[19] Cold water inlet
[20] Gas pressure test point
[21] Gas inlet
3Operation instructions
Open all the water and gas valves.
CAUTION: Hot surface!
The front of the appliance may reach high
temperatures.
3.1 Digital display - description
Operation instructions | 7
3.3 Switching the appliance on/off
Switching on the appliance
By default, the heating temperature of the
water is:
55°C preset appliances: 55°C
50°C compliant appliances: 50°C
▶ Press the button .
The screen cover shows the selected water temperature.
Fig. 2 Digital display
[1] ON/OFF button
[2] Programming button
[3] LCD panel
[4] Temperature increase button
[5] Temperature decrease button
3.2 Before first use of the appliance
CAUTION:
▶ The initial start-up of the water heater
must be done by an authorised installer
who will hand the customer the
operating instructions.
▶ Check that the type of gas indicated on the rating plate is
the same as the gas to which the appliance is connected.
▶ Plug in the appliance to the electrical socket and switch on.
▶ Open the gas isolation valve of the installation.
▶ Open the water isolation valve of the installation.
Fig. 3
Switching the appliance off
▶ Press the button .
3.4 Temperature control
The temperature indicated on the LCD
display matches the pre-selected
temperature.
▶ Press the buttons or until you reach the desired
temperature.
Fig. 4
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8 | Maintenance (only by authorised service technicians)
By selecting the temperature and only turning on the hot tap,
energy and water consumption can be reduced.
CAUTION:
The temperature indication on the display is
approximate, always confirm with your hand
before bathing children or old people.
3.5 Programming button
Setting the water temperature
Fig. 5
▶ Press the buttons or to select the desired
temperature.
▶ Press the button for 3 seconds to set the
temperature.
When the display stops flashing, the temperature is set in the
memory.
Selecting the preset temperature
To select the preset temperature.
▶ Press the button for 1 second.
The display will show the preset temperature and will supply
water at that temperature.
If draining the appliance is required, the following process
should be followed:
▶ Shut off the cold water isolation valve on the cold water
inlet off the appliance.
▶ Open a hot water tap.
▶ Remove the connection to the cold water pipe.
▶ Empty all the water contained inside the appliance.
Turning off the power to the appliance will
disable the frost protection circuit. If switching
of power is required, the appliance MUST be
drained.
3.7 Error codes
See table 4 on page 9.
Resetting the appliance
Some error codes may be solved by resetting the appliance:
▶ Press the button for 3 seconds.
3.8 Cleaning the front of the appliance
▶ Only clean the front of the appliance with a cloth and
detergent with water.
Do not use corrosive and/or abrasive
detergents.
4 Maintenance (only by authorised service
technicians)
To guarantee that the consumption of gas and the emission of
exhaust gas are maintained at the best values, we recommend
that the appliance be inspected every two years and if
necessary, maintenance works be carried out.
3.6 Draining the appliance
NOTICE:
Not draining the appliance when a freezing risk
exists may damage components of the
appliance.
Beforehand place a container below the
appliance to collect all the water that comes
out of the appliance.
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▶ Your appliance should only be attended to by a Bosch
Maintenance must only be performed by an
authorised service technician.
service agent. Call for service contract details: AU 1300 30
70 37, NZ 0800 54 33 52.
Troubleshooting | 9
5Troubleshooting
Fitting, maintenance and repair must only be carried out by authorised technicians. The following table describes the possible
solutions.
Display Description Possible solution
A0 Cold and hot water temperature sensor damaged. ▶ Check temperature sensor and associated
A1 Temperature inside the water heater housing is high
A4 Faulty air temperature sensor. ▶ Call an authorised service technician.
A7 Faulty hot water outlet temperature sensor. ▶ Check temperature sensor and associated
A9 Hot water outlet temperature sensor is not fitted
C7 Faulty fan. ▶ Check if the fan is properly connected to
CA Water flow above maximum specified value. ▶ Check incoming water pressure.
CF
C1
E0 Failure of control module ▶ Unplug the electrical connection for 10
E1 Hot water temperature sensor detects overheating. ▶ Let the appliance cool and try again.
Table 4
(heat exchanger calcified or sooted).
properly.
Low incoming gas pressure.
Blocked flue gas outlet.
Air flow insufficient for start-up.
connections.
▶ If the problem persists, call an authorised
service technician.
▶ The appliance automatically regulates its
performance to avoid overheating.
▶ If the problem persists, call an authorised
service technician.
connections.
▶ If the problem persists, call an authorised
service technician.
▶ Check temperature sensor and associated
connections.
▶ If the problem persists, call an authorised
service technician.
ECU.
▶ If the problem persists, call an authorised
service technician.
▶ Install a pressure limiting valve if necessary.
▶ Remove dirt or any other impediment from
the flue terminal and/or pipe.
▶ Close and open a hot water tap.
▶ If the problem persists, call an authorised
service technician.
seconds.
▶ Reconnect and restart the appliance.
▶ If the problem persists, call an authorised
service technician.
▶ If the problem persists, call an authorised
service technician.
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10 | Troubleshooting
Display Description Possible solution
E2 Faulty inlet water temperature sensor. ▶ Check temperature sensor and associated
connections.
▶ If the problem persists, call an authorised
service technician.
E4 Air temperature sensor detects overheating (leaking
combustion products inside the combustion
chamber).
▶ Switch off at the power point and remove
the plug from the electrical socket.
▶ Do not try to Restart the appliance.
▶ Call a service agent immediately.
E9 Activated thermal fuse. ▶ Call an authorised service technician.
EA Flame not detected. ▶ Check that the gas to the appliance has not
been turned off.
▶ Unplug the electrical connection for 10
seconds.
▶ Reconnect and restart the appliance.
▶ If the problem persists, call an authorised
service technician.
EE Modulating solenoid valve disconnected. ▶ Check solenoid connections.
▶ If the problem persists, call an authorised
service technician.
EF Wrong gas connected. ▶ Call an authorised service technician.
F7 A flame is detected although the appliance is
switched off.
▶ Unplug the electrical connection for 10
seconds.
▶ Reconnect and restart the appliance.
▶ If the problem persists, call an authorised
service technician.
F9 Safety solenoid valve disconnected. ▶ Call an authorised service technician.
FA Fault in the gas control valve. ▶ Call an authorised service technician.
FC Buttons stuck in a “pressed” position for more than
30 seconds.
▶ Release the button.
▶ If the problem persists, call an authorised
service technician.
With indication,
but without existence of
solar thermal system.
With indication
and water temperature
low.
The temperature selected is lower than the minimum
power that the appliance supplies.
High incoming water temperatures, or low flow rate
can create this occurrence.
▶ Increase the hot water flow.
-or-
▶ Select a higher temperature.
▶ If the problem persists:
▶ Call an authorised service technician.
Appliance is making a resonance noise (vibration). ▶ Call an authorised service technician.
Table 4
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Note: breakdowns diagnosed by the water heater through an
indication in the LCD panel result in the blocking of the
appliance for safety reasons. Once the problem is solved, you
have to press the on/off button for > 3 seconds to restart the
appliance.
To locate your nearest service agent, call: AU 1300 30 70 37,
NZ 0800 54 33 52.
6 Environmental considerations
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.
Environmental considerations | 11
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12 | Water quality
7 Water quality
All Bosch water heating appliances are constructed from high
quality materials and components and all are certified for
compliance with relevant parts of Australian and New Zealand
gas, electrical and water standards.
Whilst Bosch water heaters are warranted against defects, the
warranty is conditional upon correct installation and use, in
accordance with detailed instructions provided with the
heater. In the case of the water supplied to the heater, it is
important that the water quality be of an acceptable standard.
The water quality limits/parameters listed in wa ter quality table
are considered acceptable and generally, Australian and New
Zealand suburban water supplies fall within these limits/
parameters.
In areas of Australia and New Zealand where water may be
supplied, either fully or partly, from bores, artesian wells or
similar, one or more of the important limits may well be
exceeded and the heater could, therefore, be at risk of failure.
Where uncertainty exists concerning water quality, intending
appliance users should seek a water analysis from the water
supplying authority and in cases where it is established that the
water supply does not meet the quality requirements of the
water quality table, the Bosch warranty would not apply.
Water quality table
Maximum levels
pH
Index(LSI)
Saturation
6.5-9.0 +0.4 to -1.0
Table 5
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at 65 °C
(langelier)
Total
200
mg/l
Hardness
Chlorides
250
mg/l
Iron
Sodium
180
mg/l1 mg/l
8Warranty details
Robert Bosch (Australia) Pty Ltd (Bosch) Manufacturer's Warranty (Applicable for purchases from 1 January 2012)
All Bosch hot water units are carefully checked, tested and
subject to stringent quality controls.
1. Warranty
Bosch offers, at its option, to repair or exchange this Bosch hot
water unit or the relevant part listed in clause 2 below at no
charge, if it becomes faulty or defective in manufacture or
materials during the warranty period also stated in clause 2.
This warranty is offered in addition to any other rights or
remedies held by a consumer at law.
2. Warranty periods & coverage (a) Domestic applications: 3 years (parts and labour)
(b) Heat exchangers used in domestic applications: 12 years
(parts only)
(c) Commercial applications: 12 months (parts and labour)
(d) Heat exchangers used in commercial applications: 12
months (part and labour)
All warranty periods commence on the date of purchase of the
hot water unit by the end-user. However, where the date of
purchase by the end-user is more than 24 months after the
date of manufacture, all warranty periods will automatically
commence 24 months after the date of manufacture.
3. Warranty exclusions
This warranty is VOID if any damage to or failure of the hot
water unit is caused wholly or partly by:
(a) faulty installation
(b) neglect, misuse, accidental or non-accidental damage,
failure to follow instructions
(c) use of the unit for purposes other than which it was
designed or approved
(d) unauthorised repairs or alterations to the unit without
Bosch's consent
(e) use of unauthorised parts and accessories without Bosch's
consent
(f) use of non-potable water or bore wate r in the hot water unit
(see product instructions for further details)
(g) continued use after a fault becomes known or apparent.
This warranty DOES NOT include:
(a) costs of consumables or accessories
(b) wear and tear, normal or scheduled maintenance
(c) to the extent permitted by law, any damage to property,
personal injury, direct or indirect loss, consequential losses or
other expenses
(d) changes in the condition or operational qualities of the hot
Warranty details | 13
water unit due to incorrect storage or mounting or due to
climatic, environmental or other influences.
NOTE: Any service call costs incurred by the owner or user of
the hot water unit for any matter not covered by the terms of
this warranty will not be reimbursed by Bosch, even if those
costs are incurred during the warranty period. If the hot water
unit is located outside the usual operating area of a Bosch
service agent, the agent's travel, freight or similar costs are not
covered by this warranty and must be paid by the ow ner or user
of the hot water unit.
4. Warranty conditions
(a) Proof of purchase may be required.
(b) The hot water unit must be installed by an authorised and
licensed installer.
(c) Proof may be required of the date of installation and correct
commissioning of the hot water unit has been carried out to
Bosch's satisfaction (such as a certificate of compliance).
(d) Repair or replacement of the hot water unit or any parts
under this warranty does not lengthen or renew the warranty
period.
(e) This warranty is not transferable and is only offered to the
original purchaser of the hot water unit.
(f) No employee or agent of Bosch is authorised to amend the
terms of this warranty.
(g) This warranty only applies to Bosch hot water units
purchased from an authorised reseller and installed in Australia
or New Zealand.
(g) To the extent that any condition or warranty implied by law
is excludable, such condition or warranty is excluded.
5. How to lodge a warranty claim and warranty procedure
(a) Warranty claims must be made with the Bosch Customer
Contact Centre (Australia: ph 1300 307 037; New Zealand: ph
0800 543 352). Please be ready to provide the model and
serial numbers, date of installation, purchase details and a full
description of the problem. Warranty claims must be made
before the end of the warranty period.
(b) All warranty service calls must conducted by an authorised
Bosch service agent.
(c) Invoices for attendance and repair of a hot water unit by
third parties not authorised by Bosch will not be accepted for
payment by Bosch.
6. Privacy Act 1988 (Cth)
A customer's personal information collected during warranty
claims may be used for the provision of customer support, for
the provision of information about products and services and
for other marketing activities undertaken by Bosch and its
Bosch Service Agents who are authorised to carry out warra nty
repairs on behalf of Bosch (Purpose). Bosch is committed to
protecting the privacy of its cus tomers' personal information. It
will act in compliance with the National Privacy Principles and
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14 | Warranty details
Privacy Act 1988 (Cth). Bosch will not forward customers'
personal information to third parties other than for the
Purpose. A customer can object at any time to the use of their
personal information for the Purpose. Bosch will cease to use a
customer's personal information accordingly if an objection is
made.
7. Bosch contact details
If you have any questions about this warranty or to lodge a
warranty claim, please contact:
Robert Bosch (Australia) Pty Ltd
1555 Centre Road, Clayton, Victoria 3168
Tel: Australia: 1300 307 037
Tel: New Zealand: 0800 543 352
IMPORTANT NOTE FOR AUSTRALIAN CONSUMERS
Our goods come with guarantees that cannot be excluded
under the Australian Consumer Law. You are entitled to a
replacement or refund for a major failure and for co mpensation
for any other reasonably foreseeable loss or damage. You are
also entitled to have the goods repaired or replaced if the goods
fail to be of acceptable quality and the failure does not amount
to a major failure.
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Notes
| 15
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