IFD 258 · Edition 10.09
21
Parameters
4 .4 Behaviour during operation
4 .4 .1 Safety time during operation t
SB
for V1 and V2
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
IFD is also available with a safety time during operation t
SB
of
2 s. Prolonging the time increases the installation 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).
4 .4 .2 Fault lock-out or restart
Parameter 12
A switch in the lower section of the housing determines whether
the IFD starts a one-off restart or performs an immediate fault
lock-out for the burner after a flame failure, see [Behaviour in
the event of flame failure – p. 27].
Immediate fault lock-out following flame failure
Parameter 12 = 0,
Switch in fault lock-out position :
tSB
t
1
3
10
11
5
L1
04
04
88
13–14
8–9
ϑ
< 2 s
After a flame failure during operation, the IFD 258 will perform
a fault lock-out within the safety time during operation t
SB
(the
safety time during operation t
SB
is 1 second. The IFD 258 is
available with a safety time of 2 seconds upon request). At
the same time, the gas valve is closed. The fault signalling
contact closes and the display blinks and indicates
04
, see
[Program status and fault messages – p. 15].
After a fault lock-out, the IFD 258 can be reset, either by using
the button on the front panel or an external button. Several
automatic burner control units can be reset in parallel using
the external button. The IFD 258 cannot be reset by mains
failure. The fault signalling contact does, however, open as
soon as the mains voltage fails.
