Honeywell BCU 370 - Pre-Purge Time T PV

BCU 370 · Edition 01.19 58
Parameters
4.6.4 Pre-purge time t
PV
Parameter 18
88
ϑ
t
21
24
1
16
3
30
29
31
13
19-20
4
V1
6 V3
5 V2
17-18
11 DG
max.
9
32
DG
min.
7 DL
90° ➔ 0
0 ➔ 90°
t
SA1
06 H0 05 00
t
FS1
t
E
01
t
GV
P1 A2
t
PV
t
Z1
03 04
t
VZ
H8 07
t
FS2
A1 08
t
RF
t
SA2
Determines how long the full air flow will be supplied to
the combustion chamber before burner start.
Pre-purge removes non-combusted gases from the
combustion chamber.
The pre-purge time t
PV
starts once the actuator has sig-
nalled the Open position and the air pressure switch DL
contact has closed.
If “Pre-purge on each start-up” is deactivated (param-
eter 06 = 0), pre-purge is omitted on burner start after a
controlled shut-down within the last 24 hours.
If the pre-purge time t
PV
is set to 0 s, pre-purge is al-
ways omitted, e.g. even on restart after a safety shut-
down. The BCU carries out a quick start on each burner
start. The butterfly valve is moved to the Ignition posi-
tion via the Open position after controlled shut-down.
If tightness control is activated (BCU..D3, parameter
24 = 3), the pre-purge time t
PV
must be set to at least
the value of the test period (parameter 26).
The pre-purge time t
PV
is to be set on the basis of the
relevant application standard (e.g. EN 676, EN 7462,
NFPA 85 or NFPA 86).