baltur TBG 35 PN, Manual Instructions For Use

Page: 34 / 48

0002936140
5
1
2
3
4
10 / 22
0006081436_201611
E
N
G
L
I
S
H
Equipment or Safety Preventilation Pre- Post- Opening time Time travel Time travel
programmer time time ignition ignition 1st flame valve opening closing
and the 2nd flame valve damper damper
s s s s s s s
LME 22.331A2 3 30 2 2 11 12 12
LME 22.233A2 3 30 2 2 11 30 30
DESCRIPTION OF WORKING
If when the main switch is closed, the thermostats are closed, the
voltage reaches the command and control equipment which starts
the boiler. The fan motor is thus switched on to carry out the pre -
ventilation of the combustion chamber, at the same time the air
damper control servomotor moves to the opening position corre -
sponding to the maximum power setting.
At the end of the preventilation stage the air damper goes back
to the ignition flame position. If the air ventilation control pressure
switch has found that there is sufficient pressure, the ignition trans -
former will come on, and two seconds later the safety and main
valves will open.
In particular:
a) The main valve has a device to proportionally adjust the air/
gas ratio.
b) The safety valve is an ON/OFF type.
c) The air damper is activated by an electric servomotor (see
adjustment 0002933651), remember that when the burner stops
because the thermostat is triggered, the damper is moved by
the servomotor back to its closed position.
!
The flow rate of gas in the ignition flame position should
generally be greater than the minimum flow modulation. The
ignition flame position can be adjusted using the air damper
control servomotor (see 0002933651). The flame’s presence
is detected by control device and allows the equipment to
proceed to the ignition stage with the switching off of the
ignition transformer. Then the servomotor opens the air
damper progressively and the pneumatic valve allows an
increase in the gas flow up to the maximum set value.
If there is no flame, the appliance shuts down in “safety lock-out”
mode (led 20 comes on) within 3 seconds of the opening of the
main valve. In safety lock-out mode the valves are closed again
immediately. To release the appliance from safety lock-out mode,
press button (21) on the electrical panel.
MODULATION OPERATION
DESCRIPTION
When the burner is ignited at the minimum setting, if the modula -
tion probe allows it (adjusted to a temperature or pressure which is
greater than that present in the boiler) the air adjustment servomo -
tor begins to turn causing a gradual increase in the flow of combus -
tible air and consequently gas, up to the maximum flow to which
the burner is set. The increase in ventilator air pressure is detected
by the proportional gas valve sensor, which gradually adjusts the
gas flow to the air pressure variation, which is also gradual. The
burner remains in the maximum flow position until the temperature
or pressure is high enough to trip the modulation probe, which re -
verses the rotation of the air adjustment servomotor.
Reverse rotation of the servomotor, and consequently a reduction
in gas and air flow, is effected in a series of short steps. By this
method, the modulation system operates towards bringing into line
the amount of heat supplied to the boiler and the heat that the
boiler puts out to service. The modulation probe installed on the
boiler measures any variation requests and automatically adjusts
fuel and combustion air supply, by starting the air adjustment ser -
vomotor and increasing or reducing rotation as necessary. If the
limit value (temperature or pressure) at which the stop device is set
(thermostat or pressure switch) is reached even with gas supply at
minimum level, the burner is shut down by the device.
When temperature or pressure returns below the shut-down device
tripping value, the burner is activated once again according to the
program described in the previous section.