Honeywell BCU 370 - Page 20

BCU 370 · Edition 01.19 20
Function
If parameter 27 = 0, V2 closes at the
end of the main burner safety time
t
SA2
. The pilot burner is switched off.
Then the flame proving period for
the main burner t
FS2
and the con-
troller enable signal delay time t
RF
start to elapse. Afterwards, the BCU
issues the enable signal to the con-
troller.
If there is no pilot burner, program
steps
06
and
07
will be omitted.
As soon as the start-up signal (ϑ) is
switched off, post-purge starts. The
butterfly valve moves to the Igni-
tion position during this time, then
to the Closed position. Next, the
BCU rests in the start-up position/
standby.
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