Bosch T2400S 8 ND 23 Training And Service Information For After Sales page 15

The gas valve is composed by other solenoids identified as safety valves (SV + SV1 +
SV2) releasing the modulated gas to and from the solenoid gas valve.
The safety valve (SV) is the first main safety element that releases gas to the burner and
the safety valves 1 (SV1) and 2 (SV2) are the second safety level elements, that release
gas to the first and second burner segments, respectively, acting as safety and
segmentation valves.
MV1
SV2
SV1
SV3
Pict. 17 – Gas Valve in LPP version
The burner is composed by 2 segments which are fed according to the solenoid valves
activation (SV2 and/or SV3) 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 thermal sensors.
Burner
Burner
segment 1
segment 2
SV2
SV1
MV1
SV
Pict.18 – Gas valve / burner scheme for MPP
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