baltur GI 350 DSPG, Instruction

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0006080098_200302
There should also be an adequate increase in combustion air to meet the increase in fuel delivery.
Adjustment can be carried out at first regulation by operating the screws which vary the profile of the commend disk
of the combustion air regulator. Fuel and combustion air delivery both increase at the same time until they reach
maximum value (light oil pressure at the return pressure regulator is equal to about 18 ÷ 20 bar if the pressure at
the pump is at the value of 20 ÷ 22 bar). The burner remains in the maximum delivery position until the temperature
or pressure reaches the limit set for the intervention of the boiler thermostat (or pressure switch) of the 2nd stage
and makes the servomotor regulating fuel/air delivery rotate in the opposite sense of direction, a causing gradual
reduction in fuel delivery and a relative reduction in combustion air until they reach minimum value.
Should the maximum temperature (pressure, if steam boiler), be reached even with fuel and combustion air delivery
at a minimum, the thermostat (pressure switch, if steam boiler) will intervene when the value at which it has been
set is reached, and bring the burner to a standstill. When the temperature (pressure, if steam boiler) drops below
the intervention limit of the “shut down” device, the burner will start up again as previously described.
During normal operations, the boiler thermostat / pressure switch of the 2nd stage fitted to the boiler detects the
variations requested and automatically proceeds with adapting the fuel and combustion air delivery by inserting
the servomotor which regulates delivery (fuel/air). This will rotate in such a way as to obtain an increase or a de-
crease. In this way, the delivery regulating system (fuel/air) reaches a position of equilibrium which corresponds
to a fuel delivery and a relative combustion air delivery equal to the quantity of heat required by the boiler.
As in indication, it should be kept in mind that the field of variation in output obtainable with good combustion is
from 1 to 1/3 of the maximum output given on the rating plate.
Note: The air pressure switch must be set when the burner is started up and must be in function with the pressure
value verified during operations with the ignition flame; otherwise the control box will go to “shut down”.
DESCRIPTION OF OPERATIONS MODULATING
(See BT 8714/2)
The burner’s control box (cyclic relay) is connected by operating panel switch ( I ).
Control box specifications
The cyclic relay control box carries out the ignition programme by starting up the fan motor and thus the pump in
order to effect the pre-ventilation and light oil pre-circulation phases.
It is necessary that the air pressure supplied by the fan is sufficient to cause the intervention of the relative pres-
sure switch, if not, the control box will go to “shut down”.
Oil from the pump reaches the atomizer unit and circulates within it because the passages leading to the outward
and return nozzles are closed. This closure is carried out by “closing pins” applied to the ends of the rods.
These “pins” are pressed against their seats by strong springs which are situated at the opposite ends of the rods.
The oil circulates, comes out of the atomizer unit return and arrives at the return pressure regulator.
It passes through this and reaches the pump return and from there it is discharged back into the return.
Oil circulation, as described above, should be carried out at a pressure value slightly higher (by some bar) than
the minimum pressure at which the return pressure regulator has been set (10 ÷ 12 bar).
Duration of the pre-ventilation and oil pre-circulation phase is not 22,5 seconds, as foreseen by the control box,
because it is effected when the air shutter is in an open position. The pre-ventilation and pre-circulation time is
calculated by summing together the times of the following manoeuvres:
- the delivery regulation servomotor’s opening stroke (fuel/air) (45 seconds) +
- pre-ventilation time foreseen by the control box (22,5 seconds) +
- the closing stroke of the delivery regulation servomotor (fuel/air) until ignition air position (about 40 seconds).
Therefore, altogether, the duration of the pre-ventilation and oil pre-circulation phase is about 107,5 seconds.
Subsequently, the control box continues carrying out the ignition programme by connecting the ignition transformer
which feeds the electrodes with high voltage.
Control box
& relative
Programmer
LAL 1.25
Cyclic relay
Safety Time
in seconds
5
Pre-Ventilation & Oil
Pre-circulation Time
in seconds
22,5
Pre-ignition Time
in seconds
2,5
Post-ignition
Time
in seconds
5
Time between
1st flame & Start
of Modulation
in seconds
20