Bosch GWH C 920 ES Instruction Manual page 2

Index
Index
1 Warning
2 Appliance details
2.1 Features
2.2 GWH C 920 ES and GWH C 920 ESC
Specifications (Technical data)
2.3 Unpacking the tankless water heater
2.4 General rules to follow for safe operation
2.5 Dimensions and minimum installation
clearances
3 Installation instructions
3.1 Specialized tools
3.2 Introduction
3.3 Venting
3.4 Combustion air requirements
3.5 Proper location for installing your heater
3.6 Heater placement and clearances
3.7 Mounting installation
3.8 Gas piping & connections
3.9 Water connections
3.10 Water quality
3.11 Domestic hot water recirculation
3.12 Filling the condensate trap
3.13 Measuring gas pressure
4 Electrical connections
4.1 Electrical power supply
4.2 Position of the fuses in control unit
5 Operation instructions
5.1 Description of LCD Display
5.2 For your safety read before operating
your water heater
5.3 Power
5.4 Temperature selection
5.5 Use of optional remote control accessory
(part no. TSTAT2)
5.6 Operation
5.7 Reset button
5.8 Program button
5.9 Locked condition
2
3 6 Maintenance and service
6.1 Annual maintenance
6.2 Winterizing for seasonal use
4
6.3 Mineral scale build-up
4
6.4 Condensing heat exchanger unit
6.5 Adjusting CO2
5
6.6 Program values
6
6.7 Control unit diagnostics
7
8 7 Troubleshooting
7.1 Introduction
7.2 Burner does not ignite when hot water
9
is turned on
9
7.3 Water is too hot
9
7.4 Water is not hot enough
9
7.5 Low water flow/pressure
20
7.6 Hot water temperature fluctuates at tap
21
7.7 Noisy burner/heater during operation
21
21
22 8 Error codes
25 8.1 Error code diagnostics
26
27
9 Electrical diagram
28
29
10 Sensor resistance charts
30
30
11 Functional scheme
30
12 Interior components diagram
31
and parts list
31
12.1 Interior components
12.2 Components diagram
32
32
32
13 Protecting the environment
33
14 Limited Warranty
33
14.1 Limited warranty for GWH C 920 ES
33
residential model
33
14.2 Limited warranty for GWH C 920 ESC
34
commercial model
34
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