Honeywell BCU 370 - Reaction to Process Faults

BCU 370 · Edition 01.19 38
Function
3.6.1 Reaction to process faults
The BCU 370 reacts differently to process faults in different program steps. If, for example, the signal from air
pressure switch DL drops during pre-purge,
1
flashes on the display and a timeout time of 25 seconds starts to
elapse. If the signal is not applied again, the BCU carries out three further start-up attempts.
Process fault BCU 370’s reaction
Signal
(terminal)
Signal status During program step
Controlled shut-down Timeout 25 s Immediate fault lock-out Safety shut-down Start-up attempts
1)
Restart
2)
Fault message
DG
max.
(11) drops
XX
All

X
DG
min.
(9) drops
XX
All except t
SA1
+ t
SA2

4)
X
not pending after t
SA1
04
t
SA1

4)
4
not pending after t
SA2
06
t
SA2

4)
6
DL (7) pending
0
"no flow" state check
 
0
not pending
1
Operating position check
 
1
drops
P1
Pre-purge time
 
P
drops
A2
Valve moves to Ignition position
 
2
drops
02
Waiting time
 
2
drops
03
Pre-ignition time
 
3
drops
04
t
SA1
 
4
drops
05
t
FS1
 
5
drops
06
t
SA2
 
6
drops
07
t
FS2
 
7
drops
H8
Controller enable waiting time
 
8
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