BCU 460, BCU 465 · Edition 11.19
85
Parameters
Parameter A009 = 1: burner 1. The restart function is
active.
t
SA
t
Z
04
04
02
03
01
t
t
FS
t
W
t
SB
1x
>2 s
88
ϑ
V1
V2
V3
L1
1
35
L
51
22
60
61
62
96
82
If a safety shut-down occurs during operation (mini-
mum operating time of 2 s), the valves are closed and
the operation signalling contact is opened within the
safety time during operation t
SB
. The burner control
unit then attempts to restart the burner once. If the
burner does not function, a safety shut-down with fault
lock-out occurs. The display blinks and shows the fault
message.
Parameter A009 = 4: burner 1 max. 5 x in 15 min. The
restart function is active and is also monitored for ex-
cessive restarts.
In certain conditions, it is possible that the restart func-
tion is repeated continuously without a safety shut-
down with subsequent fault lock-out being performed.
The BCU has a safety shut-down with subsequent fault
lock-out option if more than 5 restarts are performed
within a period of 15 minutes.
Taking into account national standards and require-
ments, it must be clarified whether the option may be
used .
11 .6 .2 Minimum operating time t
B
Parameter A061
A minimum operating time (0 to 250 s) may be defined
to ensure that the heating equipment operates stably.
If the minimum operating time is active, burner opera-
tion will be maintained until the set time has elapsed
even if the start-up signal fails.
The minimum operating time starts as soon as the pro-
gram step for operation/controller enable (display
04
)
has been reached.
If the start-up signal drops out before the start of op-
eration/controller enable, e.g. during pre-purge, the
burner control unit reverts directly to the start-up posi-
tion (standby) and the burner is not ignited.
The minimum operating time can be cancelled by
switching off the BCU or if a safety shut-down occurs.