FCU 500, FCU 505 · Edition 02.17
106
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 max-
imum 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 position for minimum capacity (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 damaged 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 rota-
tion 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+
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
▼
