Siemens SQN72 Series - Circuit Diagrams and Control Sequences (LAL;LFL;LGK16;LOK16 - Type E); LAL;LFL;LGK16;LOK16 Type E Modulating Operation

18/20
Smart Infrastructure CC1N7802en
8/11/2021
Circuit diagrams (examples)
No. E  LAL / LFL / LGK16 / LOK16
2-stage or modulating operation  prepurging at high-fire position (NL)
*) Thermostat or similar unit with
changeover contact or 3-position
controller for OPEN/CLOSED
positioning pulses and neutral
position
**) In case of modulating operation,
fuel valve ‘BV2’ is replaced by a
gas control valve ‘
R
V’
X1
Plug
-
in space, 4
-
p
ole
X2
Plug
-
in space, 5
-
pole
X3
Plug
-
in space, 3
-
pole
F
Internal fuse
Cam disks:
I
II
III
IV
V
red
blue
orange
black
green
Program sequence diagram
shows modulating operation.