FCU 500, FCU 505 · Edition 02.17
107
Parameters
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 ca-
pacity (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 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 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+
1
2
3
46
47
48
49
50
4
67
44
52
45
51
65
66
68
41
42
16
17
18
57
13
14
15
53
54
55
56
58
62 61
5 6 7 8
11 12
FCU 500..F1
5AT
3,15AT
µC
24V
DC
88