Bosch GWI-N Series Training And Service Information page 16

Safety solenoid valve
The safety valve 1 (SV1) is the first safety element that releases gas to the burner. Safety valves 2 (SV2)
and 3 (SV3) are the second safety level elements, that release gas to the first and second burner segments,
respectively, acting as safety and segmentation valves.
Modulating valve
Mechanical modulated valve
The Gas flow (thermal load) is automatically modulated in order to ensure the correct hot water set
temperature, under water flow or temperature variations.
The burner is composed by 2 segments which are fed according to the gas flow for the injectors manifold
released by the solenoid valves activation (SV1 and/or SV2) in gas valve which can be switched over
according to the different thermal load, in order to obtain a stable combustion. These valves ensure the most
suitable condition under the control of microcomputer, based on the values detected by the water flow sensor
and hot water NTC.
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MV1
Pict. 22 – Gas Valve
Pict. 23 – gas system to burner (gas valve + manifold)
6 720 814 719 SM FP_Australia 2017/04 EN
2nd Burner
Segment
1st Burner
Segment
SV2
SV3
SV1