Honeywell BCU 370 - Position

BCU 370 · Edition 01.19 23
Function
3.2.3 Quick start, butterfly valve
waits in the Closed position
Parameter 06 = 0, parameter 28 = 1
Pre-purge will also be omitted for
this type of quick start. To prevent
cold air from entering the combus-
tion chamber while the BCU is in
start-up position/standby, the but-
terfly valve waits in the Closed posi-
tion.
The BCU 370 only carries out a
quick start if the last shut-down
was a controlled shut-down. No
more than 24 hours may have
elapsed and the BCU must have
been switched on.
After the switch-on delay time t
E
,
the butterfly valve moves to the Ig-
nition position. The Ignition position
is always approached from the top.
Therefore, the butterfly valve moves
to the Open position first.
▼
H0
05
06
07
08
00
00
H0
01
A1
A0
A2
H8
08
P9
04
03
02
Start-up with ϑ signal
Fan run up time t
GV
(P20)
Waiting time t
W
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)
Butterfly valve moves to Open position
Butterfly valve moves to Closed position
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
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
Safety time t
SA1
running
for burner/pilot burner (P12),
V1 and V2 open
Pre-ignition time t
VZ
running (P21)
Ignition activated