
BCU 480 · Edition 03.16l
66
BCU 480
12
23
SPS
PLC
API
DI
L1, N, PE
P
22
4
21
18
19
16
17
28
29
24
2
1
A
P
5
3
DI
6
VBY
µC
ϑ
1
ϑ
2
t
1
2
04
02–04 06–08
06–08 04
ϑ
1
ϑ
2
2
1
BV
IC 40
4
7
M
14
26
50 51
VAG
VAS
Project planning information
6 .18 Third gas valve (can be
shut down) on BCU . .L
Units with air valve control have an
additional contact (terminal), which
closes at the same time as the air
valve.
This can be used to activate a third
gas valve (V3). To do this, the output
of valve V1 or V2 must be used as
auxiliary energy (as a result of the
required flame control).
13
N
14 15
50 51
V3
V2
The opposite application describes
a two-stage-controlled burner
without a pneumatic air/gas ratio
control system. The third gas valve
(V3) and the air valve are activated
simultaneously. During purging/
cooling, the gas valve (V3) is not
activated.