BCU 460, BCU 465 · Edition 11.19
91
Parameters
11 .8 .5 Running time
Parameter A042
This parameter can be used to adjust the behaviour in
the case of slow opening and closing air valves. The
running time starts when the air actuator is switched
off. A restart of the burner after a controlled shut-down,
a start-up attempt, restart, cooling or purging is de-
layed until the end of the running time. After the run-
ning time has elapsed, the burner is started if the start-
up signal (
ϑ
) is applied.
The time should be adjusted such that the system can
be set to ignition position, i.e. that the air actuator is
closed before a start-up is initiated.
11 .8 .6 Over-run
Parameter A043
The over-run (t
KN
) supports applications with a pneu-
matic air/gas ratio control system and On/Off control.
Using the over-run function reduces the O
2
content in
the furnace atmosphere.
00
A4
t
t
KN
A
88
ϑ
V1
V2
L1
1
35
L
51
22
60
61
96
82
65
4
Parameter A043 = 0: Off. No over-run is performed.
The gas circuit is closed immediately owing to a quick
closing gas valve in the case of On/Off control. The air
circuit is closed more slowly. The air flowing in during
this time increases the O
2
content in the combustion
chamber.
Parameter A043 = 1: Post-ventilation (with BCU/LM..F1
only). The gas supply will be closed. Air continues to be
supplied for the programmed duration depending on
parameter A039 (in Flame mode) or A139 (in Flameless
mode).
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