Bosch 7736502488, 7736502489, 7736502490, 7736502487, 7736502496 Installation Guide

Room sealed gas continuous flow water heaters

6720808879-00.1V

Optiflow Professional

GWH12/16/20 1 CTD E23/31 F5 L

Installation 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!

6 720 810 560 (2016/06) AU

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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.1 Declaration of Conformity . . . . . . . . . . . . . . 5

2.2 Type overview . . . . . . . . . . . . . . . . . . . . . . . . 5

2.3 Included Items . . . . . . . . . . . . . . . . . . . . . . . . 5

2.4 Rating plate . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.5 Description of appliance . . . . . . . . . . . . . . . . 5

2.6 Accessory . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.7 Dimensions and minimum clearances . . . . . 6

2.8 Appliance layout . . . . . . . . . . . . . . . . . . . . . . 7

2.9 Electrical wiring diagram . . . . . . . . . . . . . . . 8

2.10 Specification . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.11 Flue accessories . . . . . . . . . . . . . . . . . . . . . 10

2.11.1 Selecting the Right Flue . . . . . . . . . . . . . . . 10

2.11.2 Vertical installation . . . . . . . . . . . . . . . . . . . 12

2.11.3 Horizontal installation . . . . . . . . . . . . . . . . . 12

3 Regulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

4 Installation (only by an authorised technicians) . 12

4.1 Important information . . . . . . . . . . . . . . . . . 12

4.2 Choice of installation site . . . . . . . . . . . . . . 13

4.2.1 Regulations concerning the installation

site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

4.2.2 Overall flue length of the installation . . . . . 13

4.3 Minimum clearances . . . . . . . . . . . . . . . . . . 13

4.4 Fitting hanging-plate . . . . . . . . . . . . . . . . . . 14

4.5 Installing the appliance . . . . . . . . . . . . . . . . 14

4.6 Water connection . . . . . . . . . . . . . . . . . . . . 14

4.7 Gas connection . . . . . . . . . . . . . . . . . . . . . . 14

4.8 Installation of flue accessories . . . . . . . . . . 15

4.9 Altitude of installation site . . . . . . . . . . . . . 15

4.10 Electrical connection (only by authorised

technicians) . . . . . . . . . . . . . . . . . . . . . . . . 16

4.10.1 Connecting the power cable . . . . . . . . . . . . 16

4.11 Commissioning of the appliance . . . . . . . . 16

4.12 Changing the setpoint limit temperature

(only for 55 °C preset appliances) . . . . . . . 16

4.13 Delivery temperature calibration . . . . . . . . 16

5 Regulating the gas (only for authorised

technicians) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

5.1 Factory settings . . . . . . . . . . . . . . . . . . . . . . 17

5.2 Service function . . . . . . . . . . . . . . . . . . . . . 17

5.3 Adjusting the appliance . . . . . . . . . . . . . . . 17

5.3.1 Access to the test points . . . . . . . . . . . . . . . 17

5.3.2 Adjusting the maximum flow

(Parameter P1) . . . . . . . . . . . . . . . . . . . . . .17

5.3.3 Adjusting the minimum flow

(Parameter P2) . . . . . . . . . . . . . . . . . . . . . .18

5.3.4 Adjusting pressure at the burner

(Parameter P0) . . . . . . . . . . . . . . . . . . . . . .18

5.4 Factory default settings . . . . . . . . . . . . . . . 19

6 Maintenance (only by authorised service

technician) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19

6.1 To remove the front panel . . . . . . . . . . . . . 19

6.2 Periodic maintenance . . . . . . . . . . . . . . . . . 20

6.3 Replacement of the fuse (electronic

control unit) . . . . . . . . . . . . . . . . . . . . . . . . .20

6.4 Start-up after completion of maintenance 20

6.5 Safe operation/ risk for prolonged use . . . 20

7 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

8 Environmental considerations . . . . . . . . . . . . . . . . 23

9 Water quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

10 Warranty details . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

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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, according

to local regulations.
▶ 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 highly 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.

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4 | Key to symbols and safety instructions

• Ensuring the appliance performs to the specifications
stated on the rating label.

• Demonstrating the operation of the appliance to the
customer before leaving.

• Handing the operating instructions to the customer.

THIS APPLIANCE IS NOT SUITABLE FOR POOL OR SPA POOL
APPLICATIONS.
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.

Installation

DANGER: Explosion Risk!

▶ Always turn off the gas valve before

carrying out any work on components
which carry gas.

DANGER: Appliance malfunction!
This appliance must be installed with no
obstructions to the flue terminal.

▶ Periodic checking of the flue terminal to

ensure no blockage or obstruction of the
openings from plants, debris or insects
must be carried out.

The installation of gas, water, and electrical
supply, and the initial startup are to be
performed by an authorised person.

Not suitable for pool or spa pool applications.
Not suitable for commercial boosting of
warm water recirculation systems.

All gas appliances require adequate air intake
to ensure correct combustion. Insects and
dirt ingress may affect combustion causing
sooting. If you notice sooting from the flue
outlet the unit would require servicing. Pest
and dirt ingress is not covered by the
manufacturers warranty.

Important information

▶ Determine the most appropriate location for the appliance.

Install as close as possible to the most frequently used hot
water outlet.

▶ Ensure the mounting structure is capable of supporting the

weight of the appliance once installed. Secure the heater to
the wall using fixings suitable for the weight of the
appliance and the wall material.

▶ Install gas and water isolation valves as close as possible to

the appliance. Only use a gate valve or full flow ball valve
(fixed mechanism type) for cold water.

▶ Check the cold water supply pressure to ensure it meets

the required supply pressure for the appliance. (see
table 5, page 9).

▶ If inlet water pressure exceeds 800 kPa a pressure limiting

valve (500 kPa) MUST be fitted. The preferable location for
the pressure limiting valve is at the water meter.

▶ Where the pressure limiting valve is less than 3 metres from

the hot water unit, it must be fitted in conjunction with a
cold water expansion valve (700 kPa), between the water
heater and the pressure limiting valve.

▶ Failure to comply with this requirement may void the

warranty.
▶ Refer to AS/NZS5601 for the relevant gas pipe sizing.
▶ After finishing the gas piping system, the pipes must be

thoroughly purged and leak tested. This test must be

performed with the gas isolation valve of the appliance

closed.
▶ Ensure the gas pressure and flow through the regulator are

appropriate for the consumption of the heater (see table 5,

page 9). Refer to AS/NZS5601 and AS3500, for the

relevant pipe size.

Note: Incorrect pipe sizing or gas supply pressure may cause
the appliance to under perform. Service calls for incorrect pipe
sizing and/or gas pressure, will NOT be covered under
warranty.

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Product details | 5

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 Declaration of Conformity

The appliance has been tested and certified to Australia
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

• Appliance documentation

2.4 Rating plate

The rating plate is located on the outside of the appliance, on

the bottom.

The rating plate has the indications on the performance of the

appliance, approval data and the serial number.

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 temperature 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
– Frost protection device

• Electrical connection: 230 V, 50 Hz

2.6 Accessory

• Flue accessories

• Mains remote control (optional).

• Bathroom remote control (optional).

2.3 Included Items

• Gas continuous flow water heater

• Fixing bracket

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6 | Product details

2.7 Dimensions and minimum clearances

Fig. 1 Dimensions (in mm)

Connections

A B C D E Cold Hot Nat. Universal

GWH12 300 570 170 120 107

GWH20 364 570 175 142 137

Table 4 Dimensions (in mm)

6 720 810 560 (2016/06) Optiflow Professional

Water Gas

LPG

½“ ½“ ½“ ½“GWH16 364 570 175 142 137

2.8 Appliance layout

Product details | 7

Fig. 2

[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

[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 shut-off valve
[19] Cold water inlet
[20] Gas pressure test point
[21] Gas inlet

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8 | Product details

2.9 Electrical wiring diagram

Fig. 3 Electrical diagram

[1] Flame sensor rod
[2] Fan
[3] Ignition electrode
[4] Power supply
[5] Connection for frost protection
[6] Connection for remote control
[7] Modulation electrovalve (gas)
[8] Segmentation electrovalve 1 (gas)

6 720 810 560 (2016/06) Optiflow Professional

[9] Segmentation electrovalve 2 (gas)
[10] Safety electrovalve (gas)
[11] Thermal fuse
[12] Water flow sensor
[13] Air temperature sensor
[14] Hot water temperature sensor
[15] Cold water temperature sensor
[16] Water valve

Product details | 9

2.10 Specification

Technical features Units GWH12 GWH16 GWH20

Performance

Nominal Gas Consumption MJ/h 90.0 120.2 149.0

Minimum gas consumption MJ/h 11.9 18.0 18.0

Efficiency at 100% of nominal load % 82.4 82.4 82.4

Gas supply data

Gas supply pressure (flowing)

Natural gas (when operating) kPa 1.13 1.13 1.13

Universal LP gas (when operating) kPa 2.75 2.75 2.75

Water supply data

Maximum permissible pressure (static) kPa 1000 1000 1000

Minimum operating pressure kPa 100 100 100

Start-up flow l/min 2.0 2.0 2.0

Maximum flow, corresponding to a temperature increase of 25 °C l/min 12.0 16.0 20.0

Maximum inlet temperature °C 50 50 50

Electrical circuit

Power supply voltage V

AC

Frequency Hz 50 50 50

Maximum power consumption W 228 228 228

230 230 230

Appliance enclosure rating IPX4D

General data

Weight (unpacked) kg 10 11 12

Height mm 570 570 570

Width mm 300 364 364

Depth mm 170 175 175

Table 5

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