14
5 Functional Description
5. 1
.4.
1 After-Running Period
The
after-running period
is
composed
of
the cooling
period
of
the flame detector (approx. 20 sec.) and an
electronic after-run period.
If
the
flame detector fails to
signal "dark" after 80 sec., the control unit initiates the
after-run electronically thus ensuring that the heater
will
be
switched off after 230 sec. or 260 sec., respec-
tively,
in
any case.
After-running time:
HL24/Air
Top
24
HL32/Air
Top
32
NOTE:
1
50
to 230 seconds
1
80
to 260 seconds
The
motor
of
the heating
and
combustion air fan always
operates
at
full load during the after-running period.
The
drive unit operates during the after-running period.
After-running serves to ventilate the combustion cham-
ber and thus to free
it
from gas and allows the heat ex-
changer to cool and
so
to prevent any damage due to
overheating.
At
the end of the after-running period, relay K2 is
deenergized and motor M stops.
The
heater is no longer
in
operation.
5. 1
.5
Fault Lock-Out
In
the
case of malfunctions the heater turns itself off
automatically. The operation indicator continues to light
until the unit is switched off at the main switch or via
the
timer. The "interlock" of the control unit can be can-
celled by switching the control unit off
and
then on
again (shut-off period min. 1 sec.).
5.
1 .5. 1 Fault Lock-Out Because
No Flame Has Materialized
- Switch-on as described under sect.
5.
1.
1
-
If
no proper combustion takes place within 120 sec.
(30
sec. preheating+ 90 sec. safety time),
or
115
sec.
(25 sec. preheating and
90
sec. safety time) if
electronic control unit
1561
GS (order
no.
241
89A)
is
used, the metering pump is switched off. Glow
plug/pencil-type glow plug and combustion
air
fan
remain in operation.
SG
1561
/ SG
1561
GT=
30
sec.
SG
1561
GS =
10
sec.
Thereafter, the start-up sequence is repeated.
- The pulsed voltage
at
control unit connector O3/C
10
via transistor V101/T is removed.
- After a preheating time of approx. 30 sec. the posi-
tive pulsed voltage
is
applied again to control unit
connector O3/C10 via transistor
V101
IT.
- Safety time (approx. 90 sec.)
and
fuel
inlet flow time
(approx. 5 sec.) start to elapse.
- After the fuel inlet flow time has elapsed, motor M
is
switched
on
again via relay
K2
and
control unit con-
nector O1/C4,
and
the start-up sequence
is
re-
peated. Should combustion still
fail
to
occur,
the
control unit will shut down the heater
in
its 'fault
lock-out' mode within another
120
sec./115 sec.,
and
an
after-running period follows.
The
operation
indicator continues
to
light.
5.1.5.2 Shut-Down Because Flame Extinguishes
During Operation (e.g. Due to Lack of Fuel)
If
the flame goes out during the combustion process
and/or the flame detector
81
signals "dark", the glow
plug/pencil-type glow plug is connected
to
the system
for max. 90
sec.
(safety time). If combustion
is
re-estab-
lished, the heater resumes normal combustion oper-
ation.
If
combustion
is
not established, metering pump and
glow plug/pencil-type glow plug are switched off after a
safety time of
90
sec. The control unit initiates the after-
running period.
5.1.5.3 Shut-Down Due to Overheating
In
the case
of
overheating, temperature limiter
82
inter-
rupts the power supply to the metering
pump.
Fuel sup-
ply is thus stopped and the flame extinguishes. Prior to
restarting, reset the temperature limiter pushing it
in.
5.1.5.4 Shut-Down
By
Means of Safety Switch
56
Safety switch
S6
interrupts the power supply to the
metering pump if the heater does not
rest
properly on
the holder (support).
5.1.5.5 Shut-Down During Preheating
if
Flame De-
tector
is
Defective
If
during preheating (25 sec./30 sec.)
the
flame detec-
tor signals "light", the heater will shut
down
in
its 'fault
lock-out' mode.
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