PFU 780 · Edition 02.12l
30
Parameters
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 nor-
mal shut-down, a start-up attempt, restart, cooling
or purging is prevented 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
program sequence to the requirements of the applica-
tion.
The time should be set such that the system can be
moved to ignition position, i.e. butterfly valves can be
closed and, possibly, gas can be flared off, before a re-
start occurs.
See examples of application Stage-controlled main
burner with alternating pilot burner and Stage-con-
trolled main burner with permanent pilot 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.