Honeywell Krom Schroder BCU 580 - Page 94

BCU 580 · Edition 11.15l 94
Parameters
Parameter 75 = 5: IGNITION to MAX. capacity; standby
in CLOSED position; burner quick start.
The control range while the burner is operating is be-
tween the positions for ignition capacity (S1) and maxi-
mum capacity (S3). The burner is ignited in the position
for ignition capacity (S1). Switching cam S2 (reverse di-
rection 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 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 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 position 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 2 116 67 4812 1115 13
S3 S4
S11
S10
0° 90°
M
IC 20
PE
S1S2
90°➔0° 0°➔90°
S1
Min Max
S2
Y-
Y+
53 54 55 56
52
1 2 3 4645
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 1210762 61