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BCU 580 · Edition 11.15l
86
Parameters
10 .6 .5 Controller enable signal delay time t
RF
Parameter 44 (only on BCU..F1/F2)
The controller enable signal is delayed by 0, 10, 20 or 30
up to 250 s using parameter 44.
If the BCU has successfully started the burner, after the
elapse of the safety time and the flame proving period,
if parameterized, the controller enable signal to the
external temperature controller is delayed. The BCU
shows program status
H8
. After the elapse of the delay
time t
RF
, the burner operation signalling contact (termi-
nals 17, 18) is closed and the controller enable output
(terminal 56) activated. The display changes to
08
.
10 .6 .6 Air actuator control
Parameter 48
In cyclic operation, parameters 48 and 49 on BCU..F1,
F2 and F3 determine the behaviour of the air actuator
during burner start.
Parameter 48 = 0: opens on external activation.
t
SA1
t
Z
04
02
03
00 A0
t
t
FS1
t
SA2
t
FS2
A8
06
07
2
10
∨
53
A
88
ϑ
1
46
1
ϑ
2
4
11
9
5
37-38
13
V1
1
2
14
V2
14
V3
57
V4
17-18
8
M
This setting together with parameter 49 = 0, see
page 89 (Air actuator can be activated externally on
start-up), is required for burners on which the air/gas
ratio is controlled by a pneumatic air/gas ratio control
system and which need to be started at low-fire rate,
e.g. on two-stage-controlled burners, see page 11
(Two-stage-controlled main burner with permanent
pilot burner). In this case, activation of the air actuator
during burner start via the input at terminal 2 must be
prevented.
External control allows switchover between low fire and
high fire during operation.
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