20068423
26
GB
Installation
5.10.2 Gas train
Type-approved in accordance with EN 676 and supplied sepa-
rately from the burner.
To select the correct model of the gas train, refer to the “burner-
gas train combination” manual supplied.
5.10.3 Gas train installation
The gas train can enter the burner from the right or left side, de-
pending on which is the most convenient, see Fig. 26.
The gas train must be connected to the gas attachment
1)(Fig. 26), with the flange 2), the gasket 3) and the screws 4)
supplied with the burner.
See the accompanying instructions for the adjustment of the gas
train.
5.10.4 Gas pressure
Tab. L indicates the pressure drop of the combustion head and
the gas butterfly valve depending on the operating output of the
burner.
Tab. L
The values shown in Tab. L refer to:
–
Natural gas G 20 NCV 9.45 kWh/Sm
3
(8.2 Mcal/Sm
3
)
–
Natural gas G 25 NCV 8.13 kWh/Sm
3
(7.0 Mcal/Sm
3
)
Column 1
Load loss at combustion head.
Gas pressure measured at the test point 1)(Fig. 27), with:
•
combustion chamber at 0 mbar;
•
burner working at maximum output;
Column 2
Pressure loss at gas butterfly valve 2)(Fig. 27) with maximum
opening: 90°.
To know the approximate output at which the burner is operating
at its maximum:
–
Subtract the combustion chamber pressure from the gas
pressure measured at test point 1)(Fig. 27).
–
Find, in the Tab. L relating to the burner concerned, column
1, the pressure value closest to the result you want.
–
Read the corresponding output on the left.
DANGER
Disconnect the electrical power using the main
system switch.
Check that there are no gas leaks.
Beware of train movements: danger of crushing of
limbs.
Make sure that the gas train is properly installed
by checking for any fuel leaks.
The operator must use appropriate tools for instal-
lation.
WARNING
The gas solenoids must be as close as possible to
the burner, to ensure that the gas reaches the
combustion head within the safety time of 3s.
Ensure that the maximum pressure to the burner
is within the calibration range of the pressure reg-
ulator.
kW
1
p (mbar)
2
p (mbar)
G 20
G 25
G 20
G 25
400
2.0
3.0
0.3
0.4
500
3.7
5.5
0.5
0.8
600
5.4
8.1
0.7
1.0
700
7.4
11.0
1.0
1.5
850
10.7
16.0
1.5
2.2
Fig. 26
D505
