Bosch T2400S 8 ND 23 Operating and installation instructions

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LOW NOX INSTANTANEOUS
GAS WATER HEATER
ROOM SEALED FAN ASSISTED / PRESSURIZED
GAS WATER HEATER
FOR INDOOR 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.

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Contents
1. INTRODUCTION ..............................................................................................3
2. APPLIANCE DESCRIPTION ............................................................................3
2.1 APPLIANCE DESIGNATION...................................................................................................... 3
2.2 AVAILABLE ACCESSORIES ..................................................................................................... 3
3. INSTALLATION ................................................................................................5
3.1 APPLIANCE FIXATION ON THE WALL ........................................................................................ 5
3.2 WATER CONNECTIONS........................................................................................................... 6
3.3 GAS CONNECTION ................................................................................................................. 6
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 ................................................................................................................................... 14
4.5 GAS VALVE ........................................................................................................................ 14
4.6 HEAT EXCHANGER.............................................................................................................. 16
4.7 WATER INLET ASSY ............................................................................................................ 17
4.8 WATER TEMPERATURE SENSORS ......................................................................................... 18
4.9 BOX TEMPERATURE SENSOR ............................................................................................... 18
4.10 WATER FLOW SENSOR..................................................................................................... 19
4.11 IGNITION ELECTRODE ....................................................................................................... 20
4.12 IONIZATION ELECTRODE.................................................................................................... 21
5. WORKING PRINCIPLE / ELECTRIC MEASUREMENTS ............................ 22
6. SERVICE ....................................................................................................... 31
7. MAINTENANCE............................................................................................. 40
8. TROUBLE SHOOTING.................................................................................. 43

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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, so always ensure after sales service have updated manuals supplied with the
product, spare part list to be used as complement of this specific service manual.
2. Appliance description
This appliance is a LOW NOx gas water heater (ErP directive demands < 56 mg/kWh),
which will replace the actual room sealed forced exhaust range of appliances offering a
wider range of modulation and installation advantages with both indoor and outdoor
models available.
2.1Appliance 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.
Example of variants:
T2400S 8/11 ND 23/31
T5600S 12/15/18 D 23/31
T5700S 12/15/18 D 23/31
W 8/10 AME 23/31
WD 8/11 AME 23/31
WTD 12/15/18-3 AME 23/31
WTD 12/15/18-4 AME 23/31
Bosch:
T–Instantaneous gas water heater
T 2400 –Fixed power with electronic ignition and power steps
T 5600 –Thermostatic control (variable power through electronic control)
T 5700 –Thermostatic control (variable power through electronic control with water valve)
T … S–Room sealed operation (indoor unit)
T … S 8 / 10 / 11 / 12 / 15 / 18 –Output (flow rate at 25ºC rise)
T … S XX D–Display
T …S XX D 23/31 –Gas type (23 = natural gas / 31 = liquefied petroleum gas)
Junkers / Vulcano:
W–GWI with Fixed power with electronic ignition and power steps
WT -3 –GWI Thermostatic control (variable power through electronic control)
WT -4 –GWI Thermostatic control (variable power through electronic control with water valve)
W/WT D–Display
W/WT D 8 / 10 / 11 / 12 / 15 / 18 –Output (flow rate at 25ºC rise)
W/WT D… AM –Room sealed operation (indoor unit)
W/WT D… AM E –Electric connection
W/WT D… AM E 23/31 –Gas type (23 = natural gas / 31 = liquefied petroleum gas)
2.2Available accessories

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Hydraulic & Gas Connections (supplied together with set of documents) with installation manual
for each destination market are the original accessories and must be used by installer (see
manual to check scope of delivery.
Remote control
Possible wired connection to both indoor (optional accessory) and outdoor versions
(included in packaging). This is done with a direct connection to the appliance with no
need to configure in the unit the existence of the wired remote control.
The kit includes 10 m of cable, which needs to be connected to the remote by opening the
back cover (rotation) and then removing 3 screws to release the circuit board and make
the connection in the available connection.
Pict. 1 –Wired remote scope of delivery
Pict. 2 –Remote Control View and connection
Anti-Freeze
Allows the protection of the appliance against water freezing inside of its pipes until -20ºC
and to be used in cases where ambient temperature can be lower than 5ºC. It is optional
for indoor models but included from factory in outdoor models.
This kit includes 6 heating elements and 1 sensor (in blue at picture) to install in the heat
exchanger and the activation is according conditions in table 1.

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Pict. 3 –Anti-Freeze Kit in appliance
Activation
Deactivation
T sensor ≤ 4ºC
T sensor ≥ 15ºC
Table 1 –Anti-freeze activation conditions
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.
3.1Appliance 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 2 –Check List for Fixation
Installer must ensure correct wall fixation and water / gas pipe positions using supplied
accessories as the wall hung bracket.
Pict. 4 –Wall Fixation Preparation

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3.2Water 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: 1- 4 bar
- Minimum pressure: 0,15 bar
- Maximum pressure: 12 bar
Table 3 –Check list hydraulic connections
3.3Gas 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 4 –Check list for gas connections
3.4Flue Exhaustion
The correspondent appliance manual have indicated the maximum flue length according model
and flue type orientation, nevertheless there is with this new line a new approach where for flue
lengths > 4 m it will be required to have configured in HMI a parameter to indicate to
Flue Exhaustion > 4 m (Note: only for MPP2 (with water valve))
▶Access menu AA.
▶Scroll until find F9.
▶Press ok
▶Scroll and select the flue length
▶Press ok
Length selected
Model
Flue Length
Parameter
12
0 –4 m
00
4 –8 m
01
8 –12 m
02
15
0 –8 m
00
17
0 –4 m
00
5 –9 m
01
Table 5 –Flue Configurations

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Pict. 5 –Wall distance in mm required in horizontal termination
Pict. 6 –Example of wall terminations in 80/110 and 60/100 type
3.5Appliance performance
Measure water flow and temperature increase to check temperature and instantaneous
water flow, assuring correct operation of the appliance.
Pict. 7 –Use of water flow meter and thermometer

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4. Components Overview
[1] Fan
[2] Temperature Limiter
[3] Heat Exchanger
[4] Burner
[5] Gas manifold
[6] Gas valve
[7] Outlet NTC
[8] Hot water
[9] Electrical supply cable
[10] Pressure switch
[11] Transformer
[12] Control Unit
[13] Ignition / Ionization Electrode
[14] Display
[15] Power switch
[16] Flow sensor
[17] Flow rate control
[18] Cold water
[19] Gas inlet
Pict.8 –Internal layout of T2400 / WD versions

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[1] Temperature limiter
[2] Thermo-fuse
[3] Burner
[4] Gas manifold
[5] Gas valve
[6] Fan
[7] Gas pipe
[8] Outlet Temperature sensor
[9] Hot water
[10] Flue collector
[11] Heat Exchanger
[12] HMI
[13] Control Unit
[14] Inlet Temperature sensor
[15] Flow sensor
[16] Cold water
[17] Flow rate control
[18] Gas inlet
[19] Electrical supply cable
Pict.9 –Internal layout of T5600 / WTD version
4.1Control panel
The control panel allows the user, installer or technician, to perform all different operations
needed. User manual explain how to access and use the HMI (human machine interface).

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Pict.10 –Control Panel HMI Overview WD-T2400 / T5600-T5700
On / Off button
The main switch is assembled on the PCB and disconnects the
unit so no voltage at components is present although anti-freeze
kit keeps active due to temperatures checks even in Off mode.
Menu Button
-Used to Enter in service mode to access service parameters
which can be used by the user, installer, technician
Program Button
-Used to Scroll back in the service mode menu when navigating
menus
OK Button
-Save value or adjust set values
-Save a temperature setting (user)
Selection button
Used to scroll inside menu ensuring navigation on parameters
inside the diagnostic mode
Table 6 –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) inside SA
(settings) parameter