Control Box Specifi Cations - Description Of Operations - baltur BT 15 N Manual De Instrucciones

CONTROL BOX SPECIFICATIONS
Burner
model
BT 15 N
BT 22 N
BT 35 N
LAL 1.25 on demand
DESCRIPTION OF OPERATION
By closing the switch on the burner, and if the relative thermostat will allow it, the resistances relay will be connected.
Voltage will reach the thermostat that commends the resistances by passing through the boiler thermostat(s);
therefore these thermostats must be closed. Control of the resistances through the boiler thermostat is to avoid the
fuel oil boiling during the control box's pauses in operations, and to avoid an unnecessary waste of electricity.
When the resistances have been connected in this way, they will heat the fuel oil in the pre-heater tank.
When the oil has been heated suffi ciently, the minimum thermostat closes.
When the minimum thermostat has been closed, if the other (regulation and safety) thermostats allow it, voltage
will reach the control box which will start functioning and connect the burner component devices according to its
programme. The burner's motor will be turned on at the same time as the ignition transformer.
The motor starts up the fan, which will carry out a pre-ventilation with air from the combustion chamber; simul-
taneously; the pump which circulates hot oil in the pipe system, expels cold oil and any gas bubbles through the
return pipe. This pre-ventilation and pre-washing phase lasts for 30 seconds and cases when the electrovalve
closes (open in the rest position) and this interrupts the free discharge of oil towards the cistern.
When the electrovalve closes, an increase in pressure in the delivery pipes follows. Ehen the pressure reaches
12,5 bar, the mechanical valve which can be found in the atomizer unit opens, oil reaches the nozzle and comes
out of it into the combustion chamber fi nely atomized.
The pressure remains at about 22 bar because the pump's pressure regulator has been set at this value.
Note: The nozzle must be chosen considering the capacity valves corresponding to an operation pressure equal
to 20 bar because there is a pressure drop (
heater fi lter.
As soon as atomized oil comes out of the nozzle, it is ignited by the spark between electrodes which has been
present since the motor started up. If the fl ame appears, the "shut down" position is passed over and the ignition
transformer is then disconnected. From the moment that the fl ame appears in the combustion chamber, the burner
is commanded and controlled by the photoresistant cell and the thermostats.
When the boiler temperature or pressure reaches the limit set on the thermostat or pressure switch, the burner
will stop. Subsequently, when the temperature or pressure drops below the re-closing limit set on the thermostat
or pressure switch, the burner starts up again. To have increased safety, it is possible to install two control ther-
mostats or pressure switches (a reserve one) regulated at different values so that if the one regulated at a lower
level does not work properly, the reserve one will intervene and bring the burner to a standstill.
Even if the safety devices have come into action, the unit starts functioning again automatically when the tem-
perature or pressure drops low enough. If for any reason during operations there should be fl ame failure, the
photoresistant cell will intervene immediately (in one second) and interrupt the supply of the washing electrovalve
which will open and rapidly discharge the pressure existing in the tank; the atomized oil spray will be intercepted
by the atomizer unit valve closing automatically, as soon as the pressure has dropped below 12,5 bar..
The start-up cycle is repeated with pre-ventilation and pre-washing and, if the fl ame ignites again normally, the
burner will resume its normal operations. If it does not, (irregular fl ame or missing fl ame) the unit goes, automa-
tically to shut down. If the programme is interrupted (voltage failure, manuel or thermostat intervention) during
the start-up cycle and subsequently re-connected (return of voltage, manual or thermostat intervention etc.) the
control box will automatically repeat from the beginning the burner's start-up cycle.
While the burner is operating, the resistances are connected and disconnected according to the requirements by
the relative thermostat, and this is indicated by a yellow light fi tted on the burner.
Control Box
OR 3/B
LMO 44
98331 ed 2007/01
Safety time Pre-ventilation and
in seconds Pre-washing time
in seconds
5
5
5
∆
p = 2 bar) caused by the antigas valve installed on the pre-
30 / 59
Post-ignition
in seconds
30
25
22,5
5
5
15