25
20035745
GB
Start-up, calibration and operation of the burner
7.7
Air pressure switch - CO check
Adjust the air pressure switch after having performed all other
burner adjustments with the air pressure switch set to the start of
the scale (Fig. 25).
With the burner running at maximum output, measure CO emis-
sion in the flue gases, then progressively obstruct the air intake
with the aid of the regulating grille 1)(Fig. 23 to page 24) and, if
this is not enough, using a rigid bulkhead, until the CO comes
close to the standard limit value (CO
1%
10.000 ppm) without
exceeding it.
In this working situation, to increase regulation, slowly turn the
special knob on the pressure switch until the burner locks out. Fi-
nally remove the obstruction from the suction inlet and check the
burner fires correctly.
7.8
Burner operation
7.8.1
Burner starting
Starting phases with progressive time intervals shown in sec-
onds:
Control device TL closes.
After about 3s:
0 s:
the control box starting cycle begins.
2 s:
the fan motor starts. Servomotor 12)(Fig. 27) starts, air
damper opens in 1
st
stage position.
3 s:
the ignition transformer is connected.
The pump 3)(Fig. 26) sucks the fuel from the tank
through the piping 1) and the filter 2) and pumps it under
pressure to delivery.
The piston 4) rises and the fuel returns to the tank
through the piping 5) - 7).
The screw 6) closes the by-pass heading towards suction
and the solenoid valves 8) - 9) - 10), de-energized, close
the passage to the nozzles.
22 s:
solenoid valves 8) and 9) open and the fuel is sprayed
out through the nozzle, igniting when it comes into con-
tact with the spark.
This is the 1
st
stage flame.
29 s:
the ignition transformer switches off.
36 s:
if the control device TR is closed or has been replaced by
a jumper wire, the 2
nd
stage solenoid valve 10) opens
and the servomotor moves the air damper to 2
nd
stage
position.
The starting cycle comes to an end.
Fig. 25
D3570
Fig. 26
D3252
*
Off
Yellow
Green
Red
For further details see page 28.
Fig. 27
D3394
LED
RMO
*
Fig. 28
D3395
LED
RMO
*
