BCU 580 · Edition 11.15
88
Parameter 75 = 5: IGNITION to MAX. capacity; standby in
CLOSED position; burner quick start.
The control range while the burner is operating is between the
positions for ignition capacity (S1) and maximum capacity (S3).
The burner is ignited in the position for ignition capacity (S1).
Switching cam S2 (reverse direction of rotation) ensures that
the position for ignition capacity is approached without pre-
purging first (quick start). 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
or alternatively with a comparable three-point step actuator.
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. If pre-purge is active,
considerably lower air capacity than the maximum air
capacity will be used for purging.
IC 20
The position for maximum capacity is achieved by the controller
enable output (terminal 56).
Switching cam settings S1, S2, S3 and S4:
S1: for minimum capacity and ignition capacity of the burner.
S2: for reversing the direction of rotation to approach the po-
sition for ignition capacity. The actuator will move to the
position for ignition capacity without reaching the position
for maximum burner capacity.
S3: for maximum capacity of the burner and pre-purge.
S4: for the closed position of the butterfly valve and standby.
S2
S3
S1
S4
0°
90°
Move to ignition position
Burner control range
CLOSED
IGNITION
Butterfly valve setting range
Control range
OPEN
Max. pos.
Ignition
pos.
Reversing direction of rotation
for quick start
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
S2
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)