Bcu 370 Program Sequence; Normal Start-Up - Honeywell BCU 370 Technical Information

Function

3 .2 BCU 370 program sequence

00
H0
H0
01
A1
Butterfly valve moves to Open position
P1
A2
Butterfly valve moves to Ignition position
03
04
05
BCU 370 · Edition 01.19
Switch on BCU 370
In the event of fault signal: reset
Start-up position/standby
Start-up with ϑ signal
Switch-on delay time t running (P22)
E
Fan run up time t (P20)
GV
Pre-purge time t running (P18)
PV
Pre-ignition time t running (P21)
VZ
Ignition activated
Safety time t running for
SA1
burner/pilot burner (P12),
V1 and V2 open
Flame proving period t
running for burner/pilot burner (P13)
FS1

3 .2 .1 Normal start-up

If a fault from the preceding operat-
ing cycle is still being signalled after
switching on, it will be necessary
to reset this first. Once the start-
up signal (ϑ) has been applied, the
switch-on delay t starts to elapse.
E
During the fan run-up time t
which follows, the fan starts with
the butterfly valve being closed. The
butterfly valve then moves from the
Closed to the Open position. After
pre-purge, it moves back to the Ig-
nition position.
The running times depend on the
respective actuator. The BCU waits
for actuator feedback before con-
tinuing the program sequence.
Now the BCU activates pre-ignition
t and then opens valves V1 and
VZ
V2 for the pilot burner. The ignition
time t is constant.
Z
After the flame proving period for
the pilot burner t , valve V3 opens
FS1
to ignite the main burner.
▼
GV
19