3425
8
GB
4.3
BURNER ADJUSTMENT
Check the output supplied, which must correspond with that requested by the oven used. To increase or
decrease its value, adjust the trimmer located on the control box (fig. 5).
Measure the gas delivery on the counter to precisely establish the burnt output. Using a smoke analyser,
measure the value of the CO
2
or the O
2
in order to optimise the burner calibration.
The correct values are:
To correct these values act on the gas valve in the following way:
To increase the gas delivery and the CO
2
:
turn the screw V1 anticlockwise (unscrew).
To reduce the gas delivery and the CO
2
:
turn the screw V1 clockwise (tighten).
Notes
: the necessary values of the pressure on the gas mains are:
- for G20 = 20 mbar
- for G31 = 37 mbar
The table below gives the possible settings for a generator.
4.4
COMBUSTION HEAD
The combustion head comprises a highly heat resistant cylin-
der whose surface features numerous holes, encased in a
metal "mesh". The air-gas mixture is pushed inside the cylin-
der and out of the head through the holes in the perimeter.
Combustion starts after the pre-purging time, when the air-
gas mixture is ignited by a spark generated by the igniter.
The metal "mesh" is the combustion head's most essential element since it improves burner performance
considerably. The flame developed on the surface of the head is perfectly retained and adheres to the mesh
when operating at the maximum setting. This allows modulating ratios as high as 6:1, avoiding the danger
of flashback when modulating is at its minimum. The flame features an extremely compact geometry, mean-
ing that there is no risk of contact between the flame and parts of the generator, consequently eliminating
the possible problem of poor combustion. The flame's structure means that smaller combustion chambers
can be developed, designed to exploit this particular feature.
4.5
EMISSIONS
The emission values of the burners are much lower than the limits laid down by the strictest standards. The
flame's distribution and its spread over a large surface means that the burner manages to limit the formation
of thermal NOx, the main causes of polluant emission.
IONISATION CURRENT
The minimum current necessary for the control
box operation is 5 µA.
The burner gives a much higher current,
meaning that checking is not usually required.
Should you want to measure the ionisation
current anyway, you must open the connector
(
CN1
) (see wiring diagram page 6) inserted in
the red wire, and insert a microammeter.
CO
2
O
2
G20
(methane)
8.5 ÷ 9%
5 ÷ 5.5%
G31
(LPG)
10 ÷ 10.7%
5.7 ÷ 6.2 %
Output
(kW)
Type of gas
Pressure P2
(mbar)
No. of turns per min.
(rpm)
CO2 (%)
Trimmer
position
10
G20
-0.1
5,800
8 - 9%
4
16
G20
-0.1
6,300
8 - 9%
10
Probe
Connectors
Control box
D7256
