BCU 560, BCU 565 · Edition 02.16
77
Parameters > Air control
11 .6 .3 Pre-ventilation time t
VL
Parameter 36
This parameter is used to define the length of time during
which the air valve is open before the normal start-up. This
time may be used for pre-purge. Suitable for burners starting
with full air capacity.
The possible settings are from 0 to 10 s in 0.1 s steps, from 10
to 250 s in 1 s steps.
t
SA1
t
Z
A2
A4
00
t
t
VL
A1
2
10
47
A
88
ϑ
46
1
11
9
5
37-38
13
V1
14
V2
17-18
PZL
After the start-up signal (
ϑ
) has been applied and after the
flame simulation check and “no flow” state check have been
conducted successfully, the air valve is opened. Start-up of the
burner commences with no interruption of the air supply after
expiry of the programmable pre-ventilation time t
VL
.
Parameter setting for this example sequence:
P23 = 0; P48 = 1; P36 > 0, see also page 74 (Air pressure
cut-out delay). The gas valve does not open until the pressure
switch has switched.
11 .6 .4 Post-ventilation time t
NL
Parameter 39
00
A0
A4
t
t
NL
2
10
47
A
88
ϑ
46
1
11
9
5
37-38
13
V1
14
V2
17-18
PZL
The air valve remains open for the programmed time (0 to 3 s)
after the start-up signal (
ϑ
) has been deactivated following a
controlled shut-down. The burner control unit closes the air
actuator (valve, actuator) after expiry of the post-ventilation
time t
NL
.
