Honeywell BCU 460 - Page 39

BCU 460, BCU 465 · Edition 11.19 39
Low NOx mode (flameless operation)
BCU 460
LM..F3
µC
FCU 500
Process control (PCC)
22
3
81
82
95
96
35
2
P
4
A
1
Start 1
6
HT
7
FLO
PLC
If there is no signal at terminal7, the system switches
from Flameless mode to Flame mode.
If the enable signal for High temperature mode
(HTmode) drops out as the furnace temperature falls,
the BCU automatically switches from Flameless 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 re-
sponsibility of the BCU. These functions must satisfy
the requirements of a protective system pursuant to EN
746-2 and be implemented externally.