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BCU 580 · Edition 11.15l
111
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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 en-
ergy (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-con-
trolled burner without a pneumatic air/gas ratio control
system. V2 and the air valve are activated simultane-
ously.
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