Technical information

IFD 258 · Edition 03.08
35 Glossary
Safety time during operation t12.5
SB
t
SB
t
1
3
10
11
5
L1
04 04
88
13–14
8–9
ϑ
If the flame fails during operation, the valves are closed within
the safety time t
SB
.
The default safety time during operation t
SB
in accordance with
EN 298 is 1 second. 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 (see Project planning
information). Note the requirements of the Standards!
Flame signal12.6
If a flame is detected, the flame detector will supply a flame
signal.
Flame detector12.7
The flame detector detects and signals the presence of a flame.
The flame detector usually consists of a flame sensor, an ampli-
fier and a relay to produce the signal. These components, with
the exception of the flame sensor itself, are accommodated
within a single housing (IFW 50).
Fault lock-out12.8
In the event of a fault lock-out, all valves are closed and a
fault signalled. Resetting must take place manually following
a fault lock-out.
Safety interlocks (Limits)12.9
The limiters in the safety interlock (linking of all the relevant
safety control and switching equipment for the use of the ap-
plication, for example STB (safety temperature limiter), Gas
min
,
Gas
max
...) must isolate input 3 from the voltage supply.
Gas valve V112.10
The gas valve V1 is opened at the start of the safety time on
start-up t
SA
. It remains open in the event of a fault, or until the
burner is switched off.
Continuous operation12.11
The gas burner has been running for longer than 24 hours
and was not switched off during that time.