Honeywell krom schroder BCU 440 - Safety Time During Operation T SB; Flame Signal; Fault Lock-Out; Safety Interlocks (Limits)

BCU 440 · Edition 01.17 35
Glossary
11.5 Safety time during operation t
SB
88
ϑ
t
1
7
9
18-19
12
16-17
t
SB
04
04
If the flame fails during operation, the valve outputs are
disconnected within the safety time t
SB
.
The default safety time during operation t
SB
in accord-
ance 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 s. Note the requirements of the Standards!
11.6 Flame signal
If a flame is detected, the flame detector will supply a
flame signal.
11.7 Fault lock-out
In the event of a fault lock-out, the valve and the igni-
tion transformer are disconnected from the electrical
power supply, and a fault is signalled. Resetting must
take place manually following a fault lock-out.
11.8 Safety interlocks (Limits)
The limiters in the safety interlock (linking of all the rel-
evant safety control and switching equipment for the
use of the application, e.g. safety temperature limiter,
minimum/maximum gas pressure) must isolate input
from the voltage supply.
11.9 Gas valve V1
The start fuel flow rate for the burner is released by
gas valve V1. It opens when the safety time on start-up
t
SA
starts to elapse. It remains open until the burner is
switched off again by a controlled shut-down or fault
lock-out.
11.10 Continuous operation
The gas burner runs continuously for more than
24 hours.