172 425 35 07-01
2(2)
ELECTRIC EQUIPMENT
Gas burner control: LFL1...
List of components
A1 Gas burner control
A3 Valve, leak tester, Dungs VPS504
B1 Ionization electrode
F1 Operating fuse
F2 Operating fuse
F3 Operating fuse
H1 Lamp, low capacity
H2 Lamp, high capacity
K1 Motor contactor with thermal overload protector
K2 Auxiliary relay
M1 Burner motor
M2 Damper Motor L&S SQN75.494A21B
S1 Operating switch
S2 Operating switch, stage 2
S3 Control thermostat
S4 Temperature limiter
S5 Micro switch for hinged door
S6 Control thermostat, stage 2
S7 Main switch
S8 Air pressure switch
S9 Gas pressure switch
S10 Gas pressure switch, max
S20 Main switch
T1 Ignition transformer
X1 Connection terminal board
X2 Earth terminal
X3 Plug-in contact, burner
X4 Plug-in contact, boiler
X5 Plug-in contact, stage 2, burner
X6 Plug-in contact, stage 2, boiler
X7 Plug-in contact, 3 phase, burner
X8 Plug-in contact, 3 phase, boiler
Y1 Gas solenoid valve 1
Y2 Gas solenoid valve 2
Function
1. Operating switch ON-Thermostat ON-Gas pressure switch ON-Air dam-
per closed.
A control is made that the air pressure switch does
not
indicate fan pressure.
Then the burner motor starts.
2. Air damper motor opens.
The air damper motor opens the damper to full load. A control is made that the
air pressure switch indicates suficient fan pressure.
3. Air damper motor closes.
The air damper motor closes to low load . Then the ignition spark is formed.
4. Main and safety valves open
The gas is ignited. The ionization electrode indicates a lame.
5. The safety time expires.
The ignition spark goes out. The safety time expires. If there is no lame or if
for some reason the lame disappears after this time limit, the burner control
locks out.
6. Operating position.
The burner is in operating position and can now change over to full load if the
operating switch and the thermostat for full load are in positon ON. The burner
can alternate between full and low load depending on set temperature.
7. Stop.
The operation of the burner can now be interrupted by means of the operating
switch or the thermostat.
•
The control locks out.
The red lamp in the control is lit. Restart the burner by pressing the reset
button.
Mains connection and fuse in accordance with local
regulations.
172 305 25 11-01
Flame monitoring and measure-
ment of ionisation current
The burner is monitored according
to the ionisation principle. Check the
ionisation current on start-up and on
each service call.
The reason for a low ionisation current
may be leaking currents, bad connec-
tion to earth, dirt or a faulty position
of the lame electrode in the burner
head. Sometimes also a faulty gas/air
mixture may cause too weak a ionisation
current.
The ionisation current is measured
by means of a microampere meter
(µA) connected in series with the
lame electrode and the gas burner
control.
Connect the µA-meter, see igure. Min.
required ionisation current according
to table. In practice this current must
be considerably higher, preferably
more than 10 µA. All the gas burners
are equipped with a ionisation cable
that can be slit which facilitates the
connection of the µA-device.
Gas pressure switches:
Adjustment range:
2,5-50 mbar GW 50
5-150 mbar GW 150
Adjustment of min. gas pressure
switch
The min. pressure switch should react
if the gas pressure is too low and
prevent the burner from starting. Too
low a gas pressure during operation
should stop the burner. The burner
may start again when the rated gas
pressure has been reached.
Remove the protective cover. Connect
a pressure gauge for measuring the
rated pressure. Decide on pressure
at which the gas switch should switch
off. Set this pressure by means of the
valve. Carefully turn the knob (see
igure) until the gas pressure switch
switches off. The value shown on the
scale should then approximately cor-
respond with the value shown on the
pressure gauge. Tolerance on scale
appr. ± 15 %. Open the ball valve.
GENERAL INSTRUCTION
Adjustemnt of max. gas pressure
switch
The burner is equipped with a max.
gas pressure switch only on request.
It should stop the burner if the gas
pressure exceeds the set value. The
burner can then only be re-started
manually (gas burner control or
overpressure switch).
Remove the protective cover. Connect
a pressure gauge for measuring the
rated gas pressure. Decide on pres-
sure at which the gas pressure switch
should switch off. Turn the adjustment
knob to this value. Tolerance on the
scale ±15%.
Adjustment of air pressure switch
The air presure switch should stop the
burner if the air volume is reduced.
The air proving device shall be adjusted
in such a way that if there is insuficient
air supply at the highest or lowest
burner operating stage, the device
operates before the supervised pres-
sure is less than 80% of the pressure
at the controlled stage and the CO
content of the combustion products
exceeds 1% by volume.
Air pressure switch:
Adjustment range ca:
1-10 mbar LGW 10
2,5-50 mbar LGW 50
Flame monitoring
Gas pressure switch, air pressure
switch
Gas control
Connection to terminal
in gas control
Min. ionisation
current required
LME
1
5 µ A
LGB
1
10 µ A
LFL
24
10 µ A
MMI 810
2
5 µ A
TMG 740-3
1
5 µ A
