Siemens LEC1/8853 Manual page 12

Double or multi-flame
supervision of gas
burners (expanding
flame burner)
Important
Legend
for the switching diagram
12
Start-up with short pre-ignition (3 s) and supervised air damper control. No load control.
Necessary flame safeguards: type LFE10... with UV-detectors QRA... or ionization field.
LK
M
Luft
Gas
GV3
GV2
7761a06/0696
GV1
Air damper control, detailed
In case of burners without air damper or with an air damper not controlled by the control unit, terminals 20, 21 and
22 must be interconnected; the path 18-c1-21 of the circuit, however, must be omitted!
A B
t8
M1 Kl.3
t7
M2 17
t11 t1
t12
LK
22/21
t2
Z
6
t3´
5
GV1
t4
GV2 7
GV3 11
FW 13/14
L2
12
A Start
A-B Normal start-up
B-C Operation
C Controlled shutdown
C-D Post-purge
D-E Closing of the air damper
E-F Burner off-period
F Restart
F-G Start-up
A
22
21
21/d1
18/c1/d1
20
LK"a"
LK"z"
t11 t1
C D E
tn t6
t5
7761d05/0696
G-H
H
H-I
I
I-K
K
K-L
L
B C
7761d04/0696
t12 t11 tn t6
F G H I
Operation
Loss of flame
Lockout
Reset
Run into start position
Restart
Start-up
Operation
D E
t12
K L
t6
t7
t1
t2
t3´
t4
t5
CC1N7761E