Siemens SQN72 Series Manual page 13

Circuit diagrams (examples)
Please note!
All of the following circuit diagrams show the start position as supplied:

End switch position II CLOSED

No voltage
No. A  LME22
2-stage or modulating operation  prepurging at high-fire position (NL)
Smart Infrastructure
X1 Plug-in space, 4-pole
X2 Plug-in space, 5-pole
I red
II blue
III orange
IV black
Program sequence diagram shows
2-stage operation.
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CC1N7802en
8/11/2021