PFU 780 · Edition 02.12
67
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 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.
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 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).
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 signal that
is detected, although there should be no flame according to
the program sequence. If such an extraneous signal is de-
tected, the flame simulation delay time t
LV
starts to elapse. If the
flame simulation is discontinued during the flame simulation
delay time t
LV
, start-up can be initiated or operation continued.
Otherwise, a fault lock-out occurs.
12 .5 Safety time during operation t
SB
tSB
t
04
04
30e
10e
28c
16c
26a
18e
L1
V1
V2
88
2e–4e
2c–4c
ϑ
If the flame fails during operation, the valve outputs are dis-
connected within the safety time t
SB
.
t