PFU 780 · Edition 02.12
35
Restart following flame failure
Parameter 12 = 1:
Restart following flame failure.
t
SA1
t
Z
04
04
03
01
t
t
FS1
t
W
t
SB
1x
>2 s
26a
16c
2c–4c
88
10e
26e
30a
28c
2e–4e
V1
1
ϑ
1
1
If the PFU detects a flame failure after a minimum operating
time of 2 s, the valves are closed and the operation signalling
contact is opened within time t
SB
.
The burner control unit now attempts to restart the burner
once. If the burner does not function, a fault lock-out occurs.
The display blinks and shows the cause of the fault.
In accordance with EN 746-2, a restart may be conducted
only if the safety of the installation is not impaired. Restart is
recommended for burners which occasionally display unstable
behaviour during operation.
The precondition for a restart is that activation of the restart
allows the burner to restart as intended (in all operating
phases). In this case, it must be ensured that the program
sequence started by the PFU matches the application.
Parameters > Behaviour during operation > Fault lock-out or restart, pilot burner