PFU 780 · Edition 02.12l
37
Parameters
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 Pro-
ject planning information).
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 involves 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 lock-out”.
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