PFU 780 · Edition 02.12
29
4 .4 .2 Minimum burner pause time t
BP
Parameter 21
Programmable time between 0 and 250 s.
t
SA2
88
08
06
07
08
t
t
BP
t
FS2
4
5
1
7
9
18-19
12
V1
14
V2
16-17
05
04
1
28-29
2
21
1
9
2
ϑ
1
ϑ
2
An immediate restart of the main burner after a normal shut-
down, a start-up attempt, restart, cooling or purging is pre-
vented by the pause time. The pause time starts when the air
valve is switched off. If a start-up signal (
ϑ
2) is applied before
expiry of this time, the start-up is delayed until the end of the
pause time.
After the pause time, the burner is started if the start-up signal
(
ϑ
) is applied.
The minimum burner pause time t
BP
serves to adapt the pro-
gram sequence to the requirements of the application.
The time should be set such that the system can be moved to
ignition position, i.e. butterfly valves can be closed and, pos-
sibly, gas can be flared off, before a restart occurs.
See examples of application Stage-controlled main burner
with alternating pilot burner and Stage-controlled main burner
The pause time has an effect on the behaviour of the main
burner only. Background: The pilot burner is only used in single-
stage operation.
Parameters > Behaviour in start-up position/standby