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Parameters
Immediate fault lock-out after installation fault
Parameter 12 = 0: Fault lock-out after installation fault.
04
04
t
SB
After an installation fault (flame failure), the burner con-
trol unit performs a fault lock-out within the safety time
during operation t
. This involves disconnecting the
SB
power from the gas valve and, if applicable, the ignition
transformer. The fault signalling contact closes, the
display blinks and shows the current program status,
see table on page 12 (Program status and fault mes-
sages).
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 BCU cannot be reset by mains failure. The fault
signalling contact does, however, open as soon as the
mains voltage fails.
BCU 440 · Edition 01.17
Restart following flame failure
Parameter 12 = 1: Restart after installation fault.
88
1
ϑ
7
9
12
16-17
18-19
t
If the BCU detects an installation fault (flame failure)
after a minimum operating time of 2 s, the valves are
closed and the operation signalling contact is opened
within time t
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 con-
ducted only if the safety of the installation is not im-
paired. Restart is recommended for burners which oc-
casionally 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 BCU matches the
application.
1x
04
01
02
04
> 2 s
t
t
SB
Z
t
t
W
SA
.
SB
88
1
ϑ
7
9
12
16-17
18-19
t
16
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