If servomotors do not drive full motion at full load curve point, the burner start-up can
be accelerated, because the servomotor running times remain shorter.
Gas use
● At full load air amount prepurge time is at least 20 s.
● 50% air amount prepurge time is at least 40 s.
● 33% air amount prepurge time is at least 60 s 33%.
● If you change the curve point setting for full load, apply the changes
also to pre-purge position settings.
● Pre-purge must ventilate combustion chamber to fresh air level.
● If servomotor Aux 3 is in use, the servomotor does not move until
phase 32 when program stop is changed to phase 32.
4.14 Ignition position
Set program stop at phase 36,
ignition
.
Burner control carries out automatic gas valve leak test during pre-purge, if:
● gas is selected as fuel, and it is the first start-up
● burner control has been unenergized
● it has been a long time from previous shutdown
● it is a start-up after safety shutdown or lockout reset
During standard stop, valve leak test is carried out before pre-purge period.
1. Servomotors drive to the ignition position. Set default values for ignition position. If
oil is selected as fuel, check oil pump operating pressure.
2. When adjustments are set, select program stop at
44 Interval 1.
As the program
moves forward, an electric arc is created.
The pre-ignition phase begins. The pre-ignition phase is longer in oil use, so that
purging period is implemented at nozzle to ensure good ignition. After the pre-
ignition phase, the fuel nozzle opens and the flame ignites. Program progress is
interrupted.
3. Optimize ignition position values.
If gas is selected as fuel in program phase 44, only the ignition gas flame (if
applicable) burns and in program phase 52, the main flame burns.
If oil is selected as the fuel, the ignition is direct, and program phases have only
different program phase durations. The ignition position setting can be adjusted in
program stop phases 36, 44 and 52.
4. Select program stop
deactivated
. The burner shifts to standard operation, phase 60,
to set minimum load. Ignition position settings become first curve point settings for
fuel/air ratio curve, that can be changed.
Set ignition position settings at the following menu level:
Params &
Display
RatioControl
GasSettings
Special
Positions
M4248 2316EN
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