Description Of Operations With Methane Gas - baltur GI 1000 Serie Mode D'emploi

DESCRIPTION OF OPERATIONS WITH METHANE GAS

The through put rate variation range available is approximately from 1 to 1/5 in respect to the maximum throughput
rate of the appliance. The burner is equipped with a limit microswitch which inhibits start-up if the flow regulator is not
set to minimum. In accordance with safety standards, burner ignition is preceded by a pre-purge stage of the
combustion chamber. During the pre-purge stage the air and gas supply regulating servomotor provides the maximum
aperture, so that pre-purge, takes place with the maximum aperture for air intake.
From the above, the total pre-ventilation time is provided by:
air shutter opening time + pre-purge time + time for return of air shutter to minimum position .
If sufficient pressure is detected by the ventilation air pressurestat, the ignition transformer will cut in at the end of the
ventilation phase and later the pilot flame valves will open. The gas will now reach the combustion head, mix with the
air delivered by the fan, and ignite. Gas throughput is regulated by the flow regulator incorporated in one of the two
pilot flame valves. The ignition transformer disconnects after the pilot flame valves open. At the end of this sequence
of events the burner will be running on pilot only. Pilot flame presence is monitored by the UV photocell.
At this point the programmer relay resets lockout position and supplies power to the main valves causing them to open.
The gas passes trough the main valves and flows out of the combustion head in the quantity permitted by the "minimum"
setting of the flow regulator valve. The main flame of the burner is now ignited at the minimum setting. The pilot circuit
cuts out after the main valves open. The modulator servo-motor cuts in after the main valves open, and on a consent
signal from the modulating thermostat or pressurestat (assuming they are set a temperature or pressure value in
excess of the temperature or pressure in the boiler), the servo-motor will start turning to provide a gradual increase in
the supply of gas and combustion air until the maximum rated flow at which the burner has been set is obtained.
N.B. Gas distribution is not determined by the main valve but by the position of the gas distribution adjustment valve
(see drawing 0002933530).
The burner continues to operate under maximum flow conditions until temperature or pressure reach a level that is
sufficient to cause one of the modulation detectors to cut in; at this point the modulator servo-motor will turn in a
reverse direction. Reverse rotation of the servo-motor, and consequently reduction in throughput of gas and combustion
air, 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 the service. During operation of the
burner, the modulating detector mounted on the boiler detects variations in the demand and automatically adjusts
the supply of fuel and combustion air by causing the modulating servo-motor to turn in increase or decrease direction.
If even at minimum throughput the threshold value (temperature or pressure) setting of the shut down device is
reached, the shut down device will operate and the burner will turn off. When the temperature or pressure drops
below the shut down device intervention threshold, the burner will cut in once again, following the sequence of
events described above. If a flame is not detected within the safeti time, the control equipment goes into "lockout"
mode (complete shut down of the burner and illumination of the lockout indicator light).
To release the lockout condition, press the reset button.
BURNER GI 1000 DSPN-D GAS PILOT
ADJUSTMENT PRINCIPLE DIAGRAM
50
(See n° 0002910770)
N° 0002933930