PFU 780 · Edition 02.12
33
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 permitted in
specific cases in the event of flame failure during start-up, if
the safety of the installation is not impaired. Note the require-
ments of the Standards! If no flame is detected during start-up,
either a fault lock-out is performed or further start-up attempts
in accordance with EN 746-2 occur.
Pursuant to NFPA 86, only one start-up attempt is permitted 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 com-
pleted, the burner control unit conducts a fault lock-out. The
display blinks and shows the cause of the fault.
Parameters > Behaviour during start-up > Burner start-up attempts