Siemens SQN72 Series - Circuit Diagrams and Control Sequences (LMO39); LMO39 2-Stage Operation (Low-Fire)

15/20
Smart Infrastructure CC1N7802en
8/11/2021
Circuit diagrams (examples)
No. B LMO39
2-stage operation  prepurging at low-fire position (KL)
1) Without oil preheater
2)
With oil preheater
*) Thermostat or similar unit with
NO contact (1
-
wire control)
X1
Plug
-
in space, 4
-
pole
X2
Plug
-
in space, 5
-
pole
Cam switches
I
red
II
blue
III
orange
IV
black
4)
One-sided approach to the target
position to eliminate the switching
differential (backlash
compensation)