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PFU 780 · Edition 02.12l
68
Glossary
12 Glossary
12 .1 Waiting time
t
W
tW
t
tZ
tSA
02
02
01
30e
10e
28c
16c
26a
18e
L1
V1
V2
88
2e–4e
2c–4c
ϑ
Once the start-up signal
ϑ
has been applied, the wait-
ing 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.
12 .2 Safety time on start-up t
SA
This refers to the period of time between switching on
and switching off of the gas valve, 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 burner
control unit.
12 .3 Ignition time t
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 trans-
former 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).
12 .4 Flame simulation/Flame simulation
delay time t
LV
t
30e
10e
28c
16c
26a
18e
L1
V1
V2
01
01
88
tW
tLV
2e–4e
2c–4c
ϑ
An extraneous signal (flame simulation) is a flame sig-
nal that is detected, although there should be no flame
according to the program sequence. If such an extrane-
ous signal is detected, the flame simulation delay time
t
LV
starts to elapse. If the flame simulation is discontin-
ued during the flame simulation delay time t
LV
, start-up
can be initiated or operation continued. Otherwise, a
fault lock-out occurs.
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