Modulation Operation Description - baltur TBML80 PN Manual De Instrucciones

DESCRIPTION OF OPERATION WITH GASEOUS
FUEL
After closing switch 1, if the thermostats are closed, the voltage
reaches the command and control equipment (switching on LED
2) which starts it working. The fan motor is thus switched on to car-
ry out preventilation of the combustion chamber, at the same time
the air shutter control servomotor moves to the opening position
corresponding to the maximum power setting.
At the end of the preventilation stage the air shutter goes back
to the ignition flame position. If the air ventilation control pres-
sure switch has found that there is sufficient pressure, the igni-
tion transformer will start (LED 4) and, two seconds later, the safe-
ty and main valves will open (LED 5).
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 shutter is activated by an electric servomotor (see
adjustment 0002933651), remember that when the burner
stops because the thermostat is triggered, the shutter is
returned by the servomotor to the 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
shutter control servomotor (see 0002933651).
The flame is detected by the control device and allows the equip-
ment to proceed to the ignition stage with the switching off of the
ignition transformer. Then the servomotor opens the air shutter
gradually 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 7 on) within 3 sec-
onds of the opening of the main valve. In safety
lock-out mode the valves are closed again im-
mediately. To release the equipment from this
safety position, press button 8 on the display
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 function,
causing a gradual increase in the combustion air flow and conse-
quently of the gas, until it reaches the maximum flow setting on the
burner. 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 re-
mains in the maximum flow position until the temperature or pres-
sure is high enough to trip the modulation probe, which reverses
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 to bring the amount of heat supplied
to the boiler in line with the heat that the boiler puts out to service.
The modulation probe installed on the boiler measures any varia-
tion requests and automatically adjusts fuel and combustion air
supply, by starting the air adjustment servomotor and increasing
or reducing rotation as necessary. If the limit value (temperature
or pressure) at which the stop device is set (thermostat or pres-
sure 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.
3 4 5
6
1
9
1 Main switch ON - OFF
2 Power LED
3 Fan LED
4 Transformer ON LED
5 2 stage LED
nd
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0006081470_201105
2 7
GAS
OIL
8 10
6 1 stage LED
st
7 Appliance shutdown LED
8 Appliance unlock button
9 Fuel fill button
10 Fuel switch
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