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T-Product · BCU 465 · 2006 April
Factory Options and Field Programmable Options
Field Programmable Options
Several field programmable op-
tions are available and can be set
by the PC-Software BC-Soft with
the optical adapter (Order Part-No.
74960437).
They also can be ordered and fac-
tory-set.
Switch-off Threshold of Flame
Amplifier,
Parameter 04
The sensitivity with which the burner
control unit still detects a flame can
be adjusted between 1 µA and
20 µA. If, for instance, the signal of
the burner to be monitored is influ-
enced by other burners (as in the
case of UV control with UVS), the set
value can be increased. The meas-
ured flame current of the selected
burner should be at least 3 µA higher
than the set switch-off threshold.
Restart Attempt, Parameter 12
This parameter determines whether
the BCU executes a restart or an
immediate fault lockout after a flame
failure of the pilot (0 = fault lockout;
1= restart).
Restart is recommended with burn-
ers, which occasionally show an un-
stable flame behavior.
Flame-simulation Test in Stand-
by Position, Parameter 15
This determines whether a test is
conducted for flame simulation with
the burner switched off (in standby
position) (= 1). This allows a fast start
of the burner since the waiting time
(t
W
) does not need to run. Prereq-
uisite: Minimum switch-off time is
4 seconds. Otherwise (= 0), flame-
simulation monitoring is performed
after the start-up signal is applied.
The waiting time (t
W
) expires before
the burner is ignited.
Minimum Burner On Time t
B
,
Parameter 20
Field programmable time in the
range of minimum trial for ignition
period t
SA
up to a maximum of 25
seconds while the burner remains in
operation. With short-term activation
of the start-up signal input (
ϑ
) (e.g.
with a pulse), the burner on time t
B
is started, that means the minimum
time the burner is in operation. This
time is not dependent on the pre-
purge time.
Minimum Burner Off Time t
BP
,
Parameter 21
Field programmable time in the
range of 0 to 250 seconds.
Immediate restarting of the burner
after shut-down is prevented by the
off time. The off time begins when
the burner is switched off. If there is
a demand for heat before this time
elapses, the start-up will be delayed
until the off time has elapsed.
After the off time has elapsed, the
burner will be started with the pend-
ing start-up signal (
ϑ
).
The time should be set in such a way
that the system can operate in a safe
ignition position, that means, that the
air valves/dampers can close, before
the burner is started again.
