BCU 480 · Edition 06.07
35
Behaviour during operation
5 .6
Safety time during operation t
5 .6 .1
SB
for pilot and main burners
Parameter 14
This indicates the safety time during operation t
SB
for valves
V1 and V2. The default in accordance with EN 298 is 1 s. The
BCU has also the available option of a safety time during
operation t
SB
of 2 s. Prolonging the time increases the instal-
lation availability in the case of brief-duration signal fades
(e.g. fades of the flame signal). In accordance with EN 746-2,
the safety time of the installation during operation (including
closing time of the valves) may not exceed 3 seconds (note
the requirements of the Standards).
Fault lock-out or restart, pilot burner
5 .6 .2
Parameter 12
This parameter determines whether the BCU starts a one-off
restart or performs an immediate fault lock-out for the burner
after an installation fault such as a flame failure or failure of
air flow (see also Project planning information).
Immediate fault lock-out following flame failure
5 .6 .3
Parameter 12 = 0: Pilot burner fault lock-out.
04
t
t
SB
04
88
4
5
1
7
9
18-19
12
V1
14
V2
16-17
1
1
ϑ
1
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.
See also parameter 32, Behaviour of the air valve in the event
of a fault lock-out.
Parameters
t
