BCU 580 · Edition 11.15
105
12 .8 Fifth or switchable gas valve on BCU . .F3
Units with air valve control have an additional contact (terminal
53/54), which closes at the same time as the air valve.
This can be used to activate a fifth gas valve. To do this, the
output of a gas valve must be used as auxiliary energy (e.g.
V2 as a result of the required flame control).
BCU..F3
13 14 15
N
V2
V3
V1
53 54
V5
57
V4
The following application describes a two-stage-controlled
burner without a pneumatic air/gas ratio control system. V2
and the air valve are activated simultaneously.
V2 must not be activated during purging.
BCU 580..F3
V1
15
13
V2
V3
V4
14
57
10
53
54
L1
ϑ
1
A
1
2
3
4
ϑ
2
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