baltur BT 75 DSNM-D, Инструкция

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12
This value is about 10 ÷ 12 bar for the 1st flame (minimum output).
Atomized fuel exiting from the nozzle, mixes with the air supplied by the fan and is ignited by the spark at the electrodes.
Flame presence is detected by the photoresistance.
The programmer continues and after 5 seconds, overcomes the locking position, turns off ignition and then, commands
2nd flame cut-in.
This operation takes place by feeding current, through the relative thermostat or pressure switch, to the motor that
controls the air inlet in the position corresponding to the 2nd flame.
Rotation of the air motor shaft allied to a suitable cam closes a contact which feeds voltage to the coil of the 2nd flame
solenoid valve. This valve closes and thus intercepts fuel flow through the 1st flame return pressure regulator.
Return fuel is now compelled to flow through the 2nd flame pressure regulator and return pressure rises up to the set
level of the regulator.
As a result, nozzle output increases and the burner now operates at maximum capacity.
Nozzle return pressure is about 18 ÷ 20 bar if pump pressure is 20 ÷ 22 bar.
Fuel and comburent air output stay at maximum level until the boiler temperature (pressure if it is a steam boiler)
reaches the level set at the 2nd flame thermostat (pressure switch in case of steam boilers) and operates the thermostat
by bringing the 1st flame back into operation. The return movement to the 1st flame position causes a reduction of
fuel output and relative combustion air.
The 1st flame on its own is not usually enough to keep pressure or temperature at the desired value and therefore,
pressure diminishes until it reaches the level at which the 2nd flame control device (pressure switch or thermostat),
again cuts in air and fuel flow totally.
The burner stops operating completely when, even with just the 1st flame cut-in, pressure or temperature reaches the
intervention level of the relevant control device (pressure switch or thermostat). The apparatus re-ignites automatically
when pressure or temperature drops below the level at which the pressure switch or thermostat has been set.
Please note that the output variation range with good combustion is roughly from 1 to 1/3 compared to the maximum
specified output.
Note: The burner is equipped with an air pressure switch that does not permit the pump motor to operate if the
combustion air pressure supplied by the fan does not reach the level at which the pressure switch has
been set. The air pressure switch must be set during burner ignition according to the pressure level noted
for 1st flame operation.