Operating Cycle - Lamborghini Caloreclima 55 PM/M-E Manuel D'installation Et D'entretien

OPERATING CYCLE

There are two types of burner operation depending on the device to which the air flap servocontrol is slaved:
with two progressive stages if the control device is the ON/OFF type, and with continuous modulation of
the flame if the device is the modulating type.
2nd stage
1st stage
startup
0
a b
Operation with two progressive stages
This can be achieved with a normal ON/OFF boiler thermostat (or pressure switch) where the servocontrol has
the air flap assume two possible positions: minimum (1st stage) opening and maximum (2nd stage) opening.
The term two progressive stages is used because the passage from one to another takes place gradually and
in a linear manner without strong variations.
The following phases of this type of operation can be noted from the diagram:
a) Stop sequence : when the burner is stopped the air flap is in a closed position to prevent air from entering
and cooling the combustion chamber of the boiler and chimney.
b) Pre-ventilation sequence : the air flap is opened all the way, then returns to a partial closing corresponding
to the start-up flow rate (with gas flow always off).
c) Start-up flame formation sequence : the gas solenoid valve coils are energized and the gas regulator is
partially opened in relation to the start-up air pressure.
d) Sequence of the passage to the main flame or second stage : the servocontrol activates the air flap opening
(to the maximum flow setting), whose increase in pressure causes a gradual increase in the gas flow rate.
e) Sequence of the passage from the maximum flow rate to the first stage : When the boiler thermostat/
pressure switch (regulator) gives the command, the servocontrol causes the air flap to close.
The resulting decrease of the pressure to the burner head leads to the progressive closing of the gas valve
until the minimum flow rate is obtained.
The burner repeats the passage from the first to second stage, from the second to the first, or stops completely,
always in relation to the command given by the boiler regulator to the servocontrol.
air
gas
e
c d
1 sec. max.
a
operation
62
time