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6.10.4 Minimum oil pressure switch
The minimum oil pressure switch (Fig. 38) is calibrated in the fac-
tory at 18 bar.
If during the start-up phase the oil pressure drop or does not
reach 18 bar, the burner goes to the ignition phase and the dis-
charge of the transformer remains for 30s without opening the oil
valve, after which there is a lockout and the display shows "Loc c
20 d0".
If during the flame the oil pressure drops below 18 bar, the burner
goes into lockout.
6.10.5 Maximum oil pressure switch
The maximum oil pressure switch (Fig. 38) is calibrated in the
factory at 3 bar.
If during the ignition phase the oil pressure in the return line goes
over 3 bar, the burner locks out.
if during the flame the oil pressure in the return line goes over 3
bar, the burner goes into lockout.
6.11
Operation
Once the start-up cycle is completed, the servomotor command
moves on to the thermostat/pressure switch that controls the
pressure or the temperature in the boiler.
If the temperature or the pressure is low, the burner progres-
sively increases the output as far as the MAX value.
If the temperature or the pressure increases, the burner pro-
gressively reduces the output as far as the MIN value. The
sequence repeats endlessly.
The burner stops when the heat request is less than the heat
supplied by the burner at MIN output.
The thermostat/pressure switch TL opens, the control box
carries out the switching off phase.
The air damper closes completely to reduce heat losses to a
minimum.
Start-up, calibration and operation of the burner
20079898
39
GB
Fig. 38
20182250
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