Honeywell Krom Schroder BCU 580 Technical Information page 91

Parameters
Parameter 75 = 2: MIN. to MAX. capacity; standby in
CLOSED position. The control range while the burner
is operating is between the positions for minimum ca-
pacity (S2) and maximum capacity (S3). The burner is
ignited in the position for ignition 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 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 in this situation .
IC 20
Switching cam setting for ignition capacity, minimum and maximum capacity
as well as pre-purge and standby:
S1: for ignition capacity of the burner.
S2: for minimum capacity of the burner.
S3: for maximum capacity of the burner and pre-purge.
S4: for the closed position of the butterfly valve and standby.
BCU 580 · Edition 11.15l
0°
62 61 5 6 7
c
MIN Burner control range
CLOSED Butterfly valve setting range
MIN
S2 S2
24V
DC
Move to ignition position
Closed Min.
S1
88
pos. pos. Ignition pos.
µC
BCU 580..F1
16 15 13 12 11
▼
9 10 11 12
MAX
c
OPEN
Control range MAX
3,15AT
Y-
Y+
8 7 6 4 3 2 1
PE
S11
S2 S1
S3
S1
Min Max
90°
S3
Max. pos.
L1
N
PE
S10
S4
91