Honeywell BCU 370 - 3.2 BCU 370 Program Sequence

BCU 370 · Edition 01.19 19
Function
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
E
starts to elapse.
During the fan run-up time t
GV
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
VZ
and then opens valves V1 and
V2 for the pilot burner. The ignition
time t
Z
is constant.
After the flame proving period for
the pilot burner t
FS1
, valve V3 opens
to ignite the main burner.
▼
H0
04
05
06
07
08
00
00
H0
01
A1
A0
P1
A2
03
H8
08
P9
Switch on BCU 370
Start-up with ϑ signal
In the event of fault signal: reset
Fan run up time t
GV
(P20)
Switch-on delay time t
E
running (P22)
Start-up position/standby
Start-up position/standby
Controlled shut-down
via ϑ signal
Flame proving period t
FS1
running for burner/pilot burner (P13)
Safety time t
SA1
running for
burner/pilot burner (P12),
V1 and V2 open
Butterfly valve moves to Open position
Butterfly valve moves to Closed position
Pre-purge time t
PV
running (P18)
Flame proving period t
FS2
running for main burner (P15)
Safety time t
SA2
running for main burner (P14),
V3 opens
Butterfly valve moves to Ignition position
Pre-ignition time t
VZ
running (P21)
Ignition activated
Controller enabler signal delay time t
RF
(P29)
Controller enable signal
Post-purge time t
PN
running (P19)
If parameter P27 = 0:
V2 is switched off
3.2 BCU 370 program sequence