Technical information

IFD 244 · Edition 03.08
20 Parameters
Behaviour during operation4.4
Safety time during operation tSB for V1 and V24.4.1
Parameter 14
This indicates the safety time during operation t
SB
for valve
V1. Standard: 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).
Restart following flame failure4.4.2
Parameter 12 = 1
t
Z
t
SA
t
W
t
SB
t
1
3
5
9
4
7–8
ϑ
L1
0201 0404
1x
88
> 2 s
If the IFD detects a flame failure after a minimum operating
time of 2 s, the valve is closed within the time t
SB
.
The automatic burner control unit now attempts to restart the
burner once.
If the burner does not function on restart, a fault lock-out oc-
curs. The display blinks and indicates
02
. After a fault lock-out,
the IFD 244 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 but-
ton. The IFD 244 cannot be reset by mains failure. The fault
signalling contact does, however, open as soon as the mains
voltage fails.
If, on restart, the automatic burner control unit detects a flame
signal within the safety time on start-up t
SA
, it continues burner
operation. The display indicates the current program status
04
.
In accordance with EN 746-2, a restart may be conducted
only if the safety of the installation is not impaired. Restart is
recommended for burners which occasionally display unstable
behaviour during operation.
The precondition for a restart is that the burner can restart as
intended (in all operating phases). It must be ensured in this
case that the program sequence started by the IFD matches
the application.