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BCU 560, BCU 565 · Edition 02.16
30
menox® low NOx mode
5 .2 BCU . .D2
The BCU coordinates the signals for starting the burner and the
fail-safe monitoring of the burner in flame mode. In menox
®
mode, the BCU switches off the ignition device and flame
control. The furnace chamber temperature must be monitored
by a safety temperature monitor (STM) for menox
®
mode. This
function must satisfy the requirements of a protective system
pursuant to EN 746-2.
Parameter 06
must be set to
5
to switch to menox
®
low
NO
x
mode. The BCU..D2 must signal via terminal 49 that the
required temperature for high temperature operation has
been reached. A higher switching point of 850°C is required
for menox
®
mode. menox
®
mode is enabled via the input at
terminal 44: depending on parameter 64, the system is either
switched over immediately or the next time the burner starts
with the parameters of menox
®
pre-ventilation time, burner
application and settings for the control element coordinated
for menox
®
mode.
Parameter settings for switching between flame mode and
menox
®
mode, see pages 63 (Burner application), 95
(menox pre-ventilation time tVLM) and 95 (Switchover to
BCU 565..C0F1
µC
49
FCU 500
Process control (PCC)
HT
38
37
18
17
1
2
3
46
50
41
44
42
ϑ
A
P
44
SPS
If there is no signal at terminal 44, the system switches from
menox
®
mode to flame mode.
If the enable signal for High temperature mode (HT mode)
drops out as the furnace temperature falls, the BCU automati-
cally switches from menox
®
mode to flame mode. To avoid
a pressure surge in the gas supply due to several burners
being switched off at the same time, it is recommended that
the furnace control unit switches the burners to flame mode
again zone by zone, for example.
Hot air compensation and ratio control are not the respon-
sibility of the BCU.
These functions must satisfy the require-
ments of a protective system pursuant to EN 746-2 and be
implemented externally.