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7.5
Atomising temperature setting
7.5.1
Thermostat for adjustment - maximum value -
minimum value
Electronic adjustment thermostat by means of information re-
layed from a PT100 probe immersed in the oil in the delivery
manifold, the thermostat adjusts spray temperature. The correct
conditions for fuel spray are shown in Fig. 19.
Example: fuel oil with 7 °E viscosity at 50 °C is pre-heated to ap-
proximately 110 °C.
IMPORTANT
Although the temperature set on the thermostat should corre-
spond to the temperature of the fluid, it is good practice to check
that the thermometer shows the correct reading once the unit has
been in operation for a few minutes. The LED will illuminate to in-
dicate that the heating resistances are working properly.
The pre-heater fitted to the burner supplies a t di 75°C at 450
kg/h (Fig. 20). If there is a t shortfall, this can be made up by an
auxiliary pre-heater.
Minimum temperature thermostat (Fig. 21), in addition to shut-
ting down the burner if the fuel temperature should fall below the
critical value for correct combustion, this thermostat also pro-
vides a permissive signal at the time of burner start-up. (Factory
set at approximately 80°C, adjustable by removing the pre-heater
cover and relative plate).
Maximum temperature thermostat (Fig. 21) this switches off
the resistance when, because of failure of the adjustment ther-
mostat, the temperature of the pre-heater increases to unaccept-
able levels; a "high temperature" alarm output is provided on the
burner terminal strip. (Factory setting is approximately 180°C).
Renewing
the
minimum
thermostats.
Reposition the probes of the new thermostat, after having first
loosened the plate pack securing screws. Make sure that the
probe is touching the resistance and the plate pack as shown in
Fig. 21.
The same precautions should be taken when renewing the resist-
ances in contact with the thermostat probes.
If the pre-heater should malfunction, use an ohmmeter to check
that the resistances located in contact with the temperature
probes are not burnt out (reading of approximately 35 Ohm).
Changing the PT100 probe in the oil delivery manifold.
Fit the supplied nut and biconical collar on the new probe, insert
a length of approximately 40mm in the manifold, and secure firm-
ly into place. At this point, the section remaining outside the man-
ifold can be bent as required, with no risk of damaging the
resistance.
Start-up, calibration and operation of the burner
and
maximum
temperature
Adjustment thermostat probe
D2747
Purge
Aluminium
plate
D2751
23
GB
Atomising temperature °C
Preheater - Output t
Thermometer
Min. thermostat
Max. thermostat
Pre-heater
Tubes into aluminium plate
D2811
Fig. 19
D2812
Fig. 20
Fig. 21
Resistance
Thermostat
probe
Fig. 22
20184179
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