Bosch GWI-N Series Operating and installation instructions

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INSTANTANEOUS GAS WATER HEATER
GWI-N
FAN PRESSURIZED GAS WATER HEATER FOR
INDOOR AND OUTDOOR INSTALLATION
TRAINING AND SERVICE INFORMATION FOR AFTER SALES
This document is restricted to exclusive use by the official service partners. Each
country should adapt the manual and its contents to the available range.
12 / 16 / 20
12
16 / 20 / 26

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Contents
1. INTRODUCTION ........................................................................................... 3
2. APPLIANCE DESCRIPTION ......................................................................... 3
2.1 APPLIANCE DESIGNATION...................................................................................................... 3
2.2 AVAILABLE ACCESSORIES ..................................................................................................... 4
3. INSTALLATION............................................................................................. 6
3.1 APPLIANCE FIXATION ON THE WALL ........................................................................................ 6
3.2 WATER CONNECTIONS........................................................................................................... 7
3.3 GAS CONNECTION ................................................................................................................. 7
3.4 APPLIANCE PERFORMANCE.................................................................................................... 7
4. COMPONENTS OVERVIEW......................................................................... 8
4.1 CONTROL PANEL................................................................................................................... 9
4.2 HEAT CELL WITH BURNER PIPES ........................................................................................... 12
4.3 GAS MANIFOLD ................................................................................................................... 13
4.4 FAN ................................................................................................................................... 15
4.5 GAS VALVE ........................................................................................................................ 15
4.6 HEAT EXCHANGER.............................................................................................................. 17
4.7 WATER INLET ASSY ............................................................................................................ 18
4.8 WATER TEMPERATURE SENSORS ......................................................................................... 18
4.9 BOX TEMPERATURE SENSOR ............................................................................................... 18
4.10 WATER FLOW SENSOR..................................................................................................... 23
4.11 IGNITION ELECTRODE ....................................................................................................... 24
4.12 IONIZATION ELECTRODE.................................................................................................... 25
5. WORKING PRINCIPLE / ELECTRIC MEASUREMENTS............................ 26
6. SERVICE..................................................................................................... 33
7. MAINTENANCE .......................................................................................... 50
8. TROUBLE SHOOTING................................................................................ 54

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1. Introduction
This manual is a complement to the instruction/operation manual delivered with the appliance, with the main
important technical details that are relevant for the official service partners and trainers in the country. In any
case one of the documents replaces the use of the other.
2. Appliance description
This appliance is a fan pressurized gas water heater, which will replace the actual room sealed range of
appliances offering a wider range of modulation and installation advantages with both indoor and outdoor
models available.
2.1 Appliance Designation
The designation allows the identification of the main characteristics of the units, especially when report is needed
through call centre or after sales technicians.
GWH –Instantaneous gas water heater
GWH 12 / 16 / 20 –Output (flow rate at 25ºC rise)
GWH 12 / 16 / 20 CT –Thermostatic control (variable power through electronic control)
GWH 12 / 16 / 20 CTD–Display
GWH 12 / 16 / 20 CTD E –Electronic ignition (source is electricity)
GWH 12 / 16 / 20 CTD E 23/31 –Gas type (23 = natural gas / 31 = liquefied petroleum gas)
GWH 12 / 16 / 20 CTD E 23 /31 F3 O–Flue less model with fan pressurized operation (outdoor unit)
GWH 12 / 16 / 20 CTD E 23 /31 F5 –Room sealed fan pressurized operation (indoor unit)
Segment
Designation
Indoor Installation
(temperature setting adjustable degree by degree)
GWH 12 CTD E 23 F5
GWH 12 CTD E 31 F5
GWH 16 CTD E 23 F5
GWH 16 CTD E 31 F5
GWH 20 CTD E 23 F5
GWH 20 CTD E 31 F5
Indoor Installation
(temperature setting locked = L)
GWH 12 CTD E 23 F5 L
GWH 12 CTD E 31 F5 L
GWH 16 CTD E 23 F5 L
GWH 16 CTD E 31 F5 L
GWH 20 CTD E 23 F5 L
GWH 20 CTD E 31 F5 L
Outdoor Installation
(temperature setting adjustable degree by degree)
GWH 12 CTD E 23 F3 O
GWH 12 CTD E 31 F3 O
Outdoor Installation
(temperature setting locked = OL)
GWH 12 CTD E 23 F3 OL
GWH 12 CTD E 31 F3 OL
Table 1 –Appliance identification of low output range (Compact 4000 S)

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GWH –Instantaneous gas water heater
GWH 16 / 20 / 26–Output (flow rate at 25ºC rise)
GWH 16 / 20 / 26 CT –Thermostatic control (variable power through electronic control)
GWH 16 / 20 / 26 CT E –Electronic ignition (source is electricity)
GWH 16 / 20 / 26 CT E 23/31 –Gas type (23 = natural gas / 31 = liquefied petroleum gas)
GWH 16 / 20 / 26 CTD E 23 /31 F6 –Flue less model with fan pressurized operation (outdoor unit)
GWH 16 / 20 / 26 CTD E 23 /31 F6 L –Temperature Locked model
GWH 16 / 20 / 26 CTD E 23 /31 F6 B –Builder Model (Professional segment)
Segment
Designation
Outdoor Installation
(temperature setting adjustable degree by degree in
control)
GWH16 3 CT E23 F6 B S2405
GWH16 3 CT E23 F6 S2405
GWH16 3 CT E31 F6 B S2405
GWH16 3 CT E31 F6 S2405
GWH20 3 CT E23 F6 B S2405
GWH20 3 CT E23 F6 S2405
GWH20 3 CT E31 F6 B S2405
GWH20 3 CT E31 F6 S2405
GWH26 3 CT E23 F6 B S2405
GWH26 3 CT E23 F6 S2405
GWH26 3 CT E31 F6 B S2405
GWH26 3 CT E31 F6 S2405
Outdoor Installation
(temperature setting locked = L)
GWH26 3 CT E23 F6 L S2405
GWH26 3 CT E23 F6 LB S2405
GWH26 3 CT E31 F6 L S2405
GWH26 3 CT E31 F6 LB S2405
Table 2 –Appliance identification of high output range (Optiflow range)
2.2 Available accessories
Remote control
Possible wired connection to both indoor (optional accessory) and outdoor versions (included in packaging)
allowing direct connection to the outside of the appliance with neither the need of configuration, nor a
connection inside of the room sealed box. The GWH 16 / 20 / 26 have internally 3 connections for Remote
control (retail version with inbuilt Bluetooth) and 4 connections for remote control (professional version).
Pict. 1 –Remote control connection to the appliance (bottom layout in 12/16/20 range)

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Pict. 2 –Remote control connection to the appliance (bottom layout in outdoor 16/20/26 range)
Pict. 3 –Remote Control with cable, connectors and instruction manual
Anti-Freeze
Allows the protection of the appliance against water freezing inside of its pipes until -20ºC (lower
environment temperature acceptable by gas valve), so to be used in cases where ambient temperature can
be lower than 5ºC. For indoor models is a kit but in outdoor models is inbuilt.
Pict. 4 –Anti-Freeze layout
The kit includes 8 resistances of 16W each, which activate under conditions from table 3.
Activation
Deactivation
T in ≤ 2ºC
T in ≥ 5ºC
or
and
T box ≤ 5ºC
T box ≥ 10ºC
Table 3 –Anti-freeze activation conditions

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3. Installation
The installation manual of each product must be checked and used by the installer in order to optimize and
leave the appliance in correct operation conditions.
Check lists for technicians/installers:
3.1 Appliance fixation on the wall
Requisite
Confirmation
Appliance is levelled and in the vertical position?
Delivered accessories are used accordingly?
Appliance is supported exclusively by the wall fixation and not by
hydraulic and/or gas connections?
Table 4 –Check List for Fixation
Pict.5 –Pre-installation distances (indoor / outdoor)
Pict. 6 –Wall Fixation Preparation (if applicable)

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3.2 Water connections
Requisite
Observations
Confirmation
Water pipes were cleaned before
connected to the appliance?
Leakage test was done
successfully?
Inlet water filter was checked and is
cleaned, ensuring the necessary
water flow?
Accessories for water connections
are adequate?
Water pressure and flow are
according to the appliance
specifications?
- Nominal pressure: 300 - 700 kPa
- Minimum pressure: 100 kPa
- Maximum pressure: 1000kPa
Table 5 –Check list hydraulic connections
3.3 Gas connection
Requisite
Confirmation
The appliance is suitable for the available gas type?
Pressure reducer and gas pipe are adequate for the required pressure and
gas flow?
Accessories for gas connection are adequate and according to the country
specification/standards?
Table 6 –Check list for gas connections
Pict. 7 –Manometer pipe connection to measure static/dynamic gas supply pressure (showing indoor version)
3.4 Appliance performance
Measure water flow and temperature increase to check temperature and instantaneous water flow, assuring
correct operation of the appliance.
Gas
manometer

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Pict. 8 –Use of water flow meter and thermometer
4. Components Overview
1 –Collector
2 –RSF box
3 –Heat exchanger
4 –Heat cell
5 –Burner
6 –Fan
7 –Gas valve
8 –Water valve
9 –Ionization electrode
10 –Ignition electrode
11 –Gas inlet
12 –Water inlet
13 –Water outlet
Pict.9 –Internal view of Indoor models (12 / 16 / 20)
1
3
2
4
6
10
9
8
7
5
11
12
13

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1 –Collector
2 –Box
3 –Heat exchanger
4 –Burner
5 –Fan
6 –Electronics
7 –Flow switch
8 –Gas valve
9 –Gas inlet
10 –Water inlet
11 –Water outlet
Pict.10 –Internal view of high output outdoor models (16 / 20 / 26)
4.1 Control panel
The control panel allows the user, installer or technician, to perform all different operations needed.
Pict.11 –Control Panel Overview (indoor model)
Pict.12 –Control Panel Overview in remote
(optional for indoor model / default for outdoor model)
9
10
11

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On / Off button
The main switch is assembled on
the PCB and disconnects phase-L
from neutral-N.
No voltage at components if the
main switch is in OFF-position
Note: Errors reset function when
pressed for more than 3 seconds
Program Button
Used to enter in different services:
-Enter in service mode
-Scroll in the service mode menu
-Save value or adjust set values
-Save a temperature set (user)
Selection button
Used to select temperature values,
adjustments and navigation on
parameters inside the visualisation
mode.
Table 7 –Control Panel Buttons
Symbol
Description
Observation
Temperature Unit:
ºC –default value
ºF –alternative value
Selection can be done by changing
default value on service mode (P6)
Power bar indicator:
Indication of the current operation
power
Indicative Value (in %)