BCU 480 · Edition 06.07
64
Glossary
12
Waiting time t
12 .1
W
tW
t
1
14
4
5
9
6
22-23
24-25
L1
V1
V2
tZ
tSA
02
02
01
88
ϑ
Once the start-up signal
ϑ
has been applied, the waiting time
t
W
starts to elapse. During this time, a self-test is conducted
to detect errors in internal and external circuit components. If
no malfunction is detected, the burner will start up.
Safety time on start-up t
12 .2
SA
This refers to the period of time between switching on and
switching off of the pilot gas valve V1, when no flame signal
is detected. The safety time on start-up t
SA
(3, 5 or 10 s) is the
minimum operating time of the burner and automatic burner
control unit.
Ignition time t
12 .3
Z
If no malfunction is detected during the waiting time t
W
, the
ignition time t
Z
then starts to elapse. Voltage is supplied to the
pilot gas valve V1 and the ignition transformer and the burner
is ignited. The duration of the ignition time is either 2, 3 or 7
seconds depending on safety time t
SA
selected.
Flame simulation/Flame simulation delay time t
12 .4
LV
t
1
14
4
5
9
6
L1
V1
V2
01
01
88
tW
tLV
24-25
22-23
ϑ
An extraneous signal (flame simulation) is a flame signal that
is detected, although there should be no flame according to
the program sequence.
If such an extraneous signal is detected, the flame simulation
delay time t
LV
starts to elapse. If the flame simulation is dis-
continued during the flame simulation delay time t
LV
, start-up
can be initiated or operation continued. Otherwise, a fault
lock-out occurs.
Safety time during operation t
12 .5
SB
tSB
t
1
14
4
5
9
6
L1
V1
V2
04
04
88
22-23
24-25
ϑ
If the flame fails during operation, the valve outputs are dis-
connected within the safety time t
SB
.
t
