baltur TBG 120 P Installation, Use And Maintenance Instruction Manual page 52

ENGLISH
OPERATING DESCRIPTION
The gas train supplied with the burner is composed of an ON/OFF
safety valve and a single stage slow opening main valve.
The fuel flow rate regulation in the first and second stage is carried
out by a streamlined butterfly valve -6, activated by the electric
servomotor -7 .
The movement of the air shutter -8 is produced by the rotation of
the servomotor -7 through a lever and strap system -34. **inserire-
traduzione** When the main switch -1 turns on, if the thermostats are
on, voltage reaches the control box which starts the burner -2.
This turns on the fan motor -3 for pre-ventilation of the combustion
chamber. The rotation of the control servomotor -7 occurs at the same
time and brings the gas throttle -6 and the air shutter -8 in the opening
position corresponding to the second flame, by leverage.
At the end of the pre-ventilation stage, the gas throttle and the air
shutter are returned to the first flame position, then the ignition
transformer -4 comes on and, 2 seconds later, the gas valves -5 open.
The presence of the flame, detected by the control device, permits
continuation and completion of ignition, turning off the transformer.
Then passing on to the second stage of power through the progressive
opening of the gas throttle and the air gate at the same time .
At the moment in which the demand for heat from the system is
satisfied, the boiler thermostat will intervene and shut down the boiler.
The air shutter, through the rotation of the servomotor, will reach the
closed position when inactive.
In the event that the control device does not detect the presence of a
flame, the control box activates a "safety lock-out" within 3 seconds
of the opening of the main gas valve. In "safety lock-out" mode the
valves are immediately closed again. To reset the control box from its
safety position, press the reset button -9.
1 Main on/off switch
2 Thermostat on indicator light
3 Fan motor indicator light
4 Ignition transformer indicator light
5 Gas valves' indicator light
9 Lock button
10 Reset button
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TWO-STAGE GAS BURNER
When the two-stage burner is installed on a boiler for the production of
hot water for heating purposes, it must be connected so it can operate
at the maximum output by stopping completely, without switching to
the first-stage operation, when the set temperature is reached.
If the burner has switched to the first-stage operation, the boiler
would be loaded insufficiently and so flue gas would come out at
a temperature below the dew point giving rise to the presence of
condensation water in the flue.
To obtain this particular operation, do not install the second stage
thermostat but make a direct connection between the terminals of the
4-pole connector (jumper).
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