BCU 580 · Edition 11.15
12
1 .1 .5 Flame control using the temperature
FCU 500..H1
M
HT
18
HT
HT
BCU 580..D
49
5
8
µC
BCU 580..D
49
5
8
µC
5-8
STM
In high temperature systems (temperature > 750°C), the flame
may be controlled indirectly via the temperature.
As long as the temperature in the furnace chamber is below
750°C, the flame must be controlled by conventional methods.
If the temperature in the furnace chamber rises above the
spontaneous ignition temperature of the gas/air mixture
(> 750°C), the FCU signals to the downstream burner control
units via the fail-safe HT output that the furnace system is in
High temperature mode (HT). When the HT input is activated,
the burner control units switch to High temperature mode.
They operate without evaluating the flame signal and their
internal flame control is non-functional.
If the furnace temperature falls below the spontaneous igni-
tion temperature (< 750°C), the FCU disconnects the HT output
from the electrical power supply. As soon as the signal to the
HT inputs of the burner control units is no longer present, the
flame signals are once again monitored by a UV sensor or
ionization electrode.
In the event of a fault in a temperature monitoring component
(e.g. sensor discontinuity, sensor short-circuit) or in the event
of a mains failure, the flame control task is transferred to the
burner control units.
Application > Examples of application
