BCU 580 · Edition 11.15l
93
Parameters
Parameter 75 = 4: MIN. to MAX. capacity; standby in
position for MIN. capacity; burner quick start.
The control range while the burner is operating is be-
tween the positions for minimum capacity (S4) 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 position for minimum capac-
ity (S4).
This operating mode can be achieved with an actua-
tor 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 may be dam-
aged by the hot furnace atmosphere as a result of the
lowest possible position of the butterfly valve, limited
by S4 . If pre-purge is active, considerably lower air
capacity than the maximum air capacity will be used
for purging .
IC 20
Switching cam setting for ignition capacity, minimum and maximum capacity
and reverse direction of rotation to approach the position for ignition capacity:
S1: for ignition capacity of the burner.
S2: for reversing the direction of rotation to approach the position for ignition
capacity.
S3: for maximum capacity of the burner and pre-purge.
S4: for the closed position of the butterfly valve and standby.
S4
S2
S3
S1
0°
90°
Move to ignition position
Burner control range
Butterfly valve setting range
Control range
Max. pos.
OPEN
Ignition
pos.
Reversing direction of rotation
for quick start
Min.
pos.
Closed
pos.
MIN
MIN
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
▼