PFU 780 · Edition 02.12l
34
Parameters
Main burner
Parameter 11
This indicates the number of possible start-up attempts
of the main burner.
In accordance with EN 746-2, three start-ups are per-
mitted in specific cases in the event of flame failure
during start-up, if the safety of the installation is not
impaired. Note the requirements of the Standards! If no
flame is detected during start-up, either a fault lock-out
is performed or further start-up attempts in accord-
ance with EN 746-2 occur.
Pursuant to NFPA 86, only one start-up attempt is per-
mitted in the event of flame failure during start-up. For
units approved by FM Approval (see type label), it is
only possible to select one start-up attempt.
1 start-up attempt
Parameter 11 = 1
t
SA1
t
Z
04
06
02
03
00
t
t
FS1
t
SA2
06
26a
16c
18e
2c–4c
18a
14a
88
10e
26e
30a
28c
2e–4e
6a–6e
V1
1
V2
2
ϑ
1
ϑ
2
2
1
If no flame forms during the start-up of the main burner,
a fault lock-out is performed after expiry of time t
SA2
.
The display blinks and shows the cause of the fault.
2 or 3 start-up attempts
Parameter 11 = 2, 3
t
SA2
t
SA2
t
SA2
t
SA1
t
Z
04
06
02
03
00
t
t
FS1
06
t
W
06
06
05
05
t
W
26a
16c
18e
2c–4c
18a
14a
88
10e
26e
30a
28c
2e–4e
6a–6e
V1
1
V2
2
ϑ
1
ϑ
2
2
1
If several start-up attempts are set and if the PFU does
not detect a flame signal during start-up, it closes valve
V2 after the safety time t
SA2
has expired and attempts
to start up again. After the last programmed start-up
attempt has been completed, the burner control unit
conducts a fault lock-out. The display blinks and shows
the cause of the fault.