BCU 580 · Edition 11.15
86
Parameter 75 = 3: IGNITION to MAX. capacity; standby in
CLOSED position.
The control range while the burner is operating is between the
positions for minimum capacity (S1) and maximum capacity (S3).
The burner is ignited in the position for minimum capacity (S1).
When the burner is switched off, the actuator is moved to the
closed position (S4).
This operating mode can be achieved with an actuator IC 20,
RBW or alternatively with a comparable three-point step ac-
tuator.
If the air supply is stopped on a heated furnace with the
burner switched off, the controls are protected from the
hot furnace atmosphere as a result of the butterfly valve
being in the closed position (limited by S4). Check whether
the burner can cope without cooling in this situation.
IC 20
Switching cam setting for ignition capacity, minimum and
maximum capacity as well as pre-purge and standby:
S1: for minimum capacity and ignition capacity of the burner.
S3: for maximum capacity of the burner and pre-purge.
S4: for the closed position of the butterfly valve and stand-
by.
0°
90°
S4
S1
S3
Move to ignition position
Burner control range
CLOSED
IGNITION
Butterfly valve setting range
Control range
Ignition pos.
Max. pos.
OPEN
Min.
pos.
Closed
pos.
MIN
MAX
MAX
PE
L1
N
3 2 1
16
6
7
4
8
12 11
15
13
S3
S4
S11
S10
0°
90°
M
IC 20
PE
S1
S2
90°
➔
0°
0°
➔
90°
S1
Min
Max
Y-
Y+
53
54
55
56
52
1
2
3
46
45
65
66
67
68
49
50
51
17
18
37
38
13
14
15
BCU 580..F1
3,15AT
µC
88
c
c
41
42
24V
DC
5 6
9
11 12
10
7
62 61
Parameters > Air control > Capacity control (bus)
▼