PFU 780 · Edition 02.12
36
4 .6 .3 Fault lock-out or restart, main burner
This parameter determines whether the PFU starts a one-off
restart or performs an immediate fault lock-out for the main
burner after a flame failure (see also Project planning infor-
mation).
Immediate fault lock-out following flame failure
Parameter 13 = 0:
Main burner fault lock-out
08
t
t
SB
08
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
After a flame failure, the burner control unit performs a fault
lock-out within the safety time during operation t
SB
. This in-
volves disconnecting the power from the gas valves and the
ignition transformer. The fault signalling contact closes, the
display blinks and shows the current program status (see
table “Program status and fault messages”).
After a fault lock-out, the burner control unit can be reset,
either with the button on the front panel or using an external
button. Several burner control units can be reset in parallel
using the external button.
The PFU cannot be reset by mains failure. The fault signalling
contact does, however, open as soon as the mains voltage fails.
See also “Behaviour of the air valve in the event of a fault
Parameters > Behaviour during operation
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