14/22
Building Technologies CC1N7435en
HVAC Products 11.01.2007
Connection diagrams
LGB21...
Flame supervision
Burner controls for 1- or 2-stage forced draft burners.
Air damper control for prepurging with low-fire air volume.
LGB21...: With ionization probe or auxiliary unit AGQ1...A27 for UV detector
QRA...
GP/SB
R/W
M
12
3
6
11
7
4
5
1
7435f01/1299
ABB´CD
tw
t10
t1
TSA
t3
t4
LP
Z
BV1
FS
BV2
Application examples
Control of actuators of 2-stage or 2-stage modulating burners.
Prepurging («t1») with low-fire air volume.
Same low-fire actuator position (switching cam III) during startup and
operation!
For information about actuators «SA»:
SQN3...: Refer to Data Sheet N7808
SQN7...: Refer to Data Sheet N7804
SQN9...: Refer to Data Sheet N7806
12 2 10 8 3 6 11 7 9 4 5 1
GP/SB
W
R
HS
0
I
L
N
AL
EK2
M
LP
bv1
bv2
Dbr1
Z
BV2
ION
7435a09/0704
BV1
Si
LGB2...
LR
SA
BV1
RV
II
KL
Zu
III
LKP
NL
t1
IV
III
IV
I
t
IV
12 2
10
8
3
6
11
9
7
4
5
1
HS
0
I
NL
AL
EK2
M
LP
GP
R/W
Z
BV1
(*)
LR
ION
BV2
*
(*)
N1
2
6
7
5
4
3
b1
b2
B
a
b
III
a3
a
b
II
MS
I
a
b
a2
a
b
IV
A
a
b
V
RV
LK
7435a01/0704
Dbr1
a1
SA
Si
SB
SQN3...121...
* Note:
With 2-stage modulating burners (with gas control damper «RV»),
«BV2» and the dotted connection between terminals (*) are not
required
12 2 10 8 3 6 11 9 7 4 5 1
AL
EK2
M
LP
GP
R/W
Dbr1
Z
BV1
LR
ION
BV2
HS
NL
0
I
N
N
12
53
6
4
7435a02/0704
LK
SA
IV
II
MS
I
C3
D
K2
C31
III
R32
R1
V
K1
a
b
ab ab ba
a
b
-
+
+
Si
SB
SQN91.140... / 2-stage control