Riello BS2D Instrucciones De Instalación, Uso Y Mantenimiento página 21

5.10.3 Gas train
Approved according to standard EN 676 and provided separately
from the burner. For its adjustment see the enclosed instructions.
Disconnect the electrical power using the main
switch.
DANGER
Check that there are no gas leaks.
Pay attention when handling the train: danger of
crushing of limbs.
Make sure that the gas train is properly installed
by checking for any fuel leaks.
The operator must use the required equipment
during installation.
5.10.4 Gas pressure
Tab. I indicates the pressure drops of the combustion head and
gas butterfly valve, on the basis of the burner operating output.
The values shown in Tab. I refer to:
- Natural gas G 20 NCV 9.45 kWh/Sm
- Natural gas G 25 NCV 8.13 kWh/Sm
Column 1
Combustion head pressure drop.
Gas pressure measured at test point M2)(Fig. 16 on page 18),
with:
• combustion chamber at 0 mbar;
• burner working at maximum output
To calculate the approximate output at which the burner oper-
ates:
- subtract the pressure in the combustion chamber from the
pressure of the gas at test point M2)(Fig. 16 on page 18).
- Find, inTab. I related to the burner concerned, the pressure
value closest to the result of the subtraction.
- Read the corresponding output on the left.
Example with G 20 natural gas for BS2D TL:
Maximum output operation
Gas pressure at test point M2)(Fig. 16 on page 18)=
Pressure in combustion chamber
A pressure of 7.8 mbar, column 1, corresponds in Tab. I to an out-
put of 91 kW.
This value serves as a rough guide; the effective output must be
measured at the gas meter.
3
(8.2 Mcal/Sm
3
(7.0 Mcal/Sm
=
10 - 2.2 =
Installation
kW
49
54
58
63
68
72
77
82
86
91
79
92
105
118
131
143
156
169
182
195
140
152
164
177
189
201
213
226
238
250
3
)
3
)
To calculate the required gas pressure at test point M2)(Fig. 16
on page 18), with the maximum modulating output at which you
want the burner to operate having been fixed:
- find the nearest output value in Tab. I for the burner in ques-
tion.
- Read on the right, column 1, the pressure at the socket
M2)(Fig. 16 on page 18).
- Add this value to the estimated pressure in combustion
chamber.
Example with G 20 natural gas for BS2D TL:
Operating at the desired maximum output: 91 kW
Gas pressure at an output of 91
Pressure in combustion chamber
pressure required at the test point M2)(Fig. 16 on page 18).
10 mbar
2.2 mbar
WARNING
7.8 mbar
19 GB
p (mbar)
G 20 G 25
2.8 3.92
3.2 4.48
3.6 5.01
4.1 5.74
4.7 6.58
5.1 7.14
5.8 8.12
6.5 9.1
7.0 9.8
7.8 10.92
2.0 2.8
2.6 3.64
3.3 4.62
4.2 5.88
5.1 7.14
6.1 8.54
7.3 10.22
8.7 12.18
10.2 14.28
11.9 16.66
4.1 5.74
4.6 6.44
5.2 7.28
5.9 8.26
6.6 9.24
7.3 10.22
8.1 11.34
9.0 12.6
9.8 13.72
10.8 15.12
7.8 + 2.2
The data of thermal output and combustion
head gas pressure are related to full open (90°)
gas butterfly valve.
G 31
3.8
4.8
5.5
6.3
7
7.5
8.2
9
9.8
11
3.8
4.6
5.6
6.6
7.7
8.7
9.9
11.1
12.3
13.5
3.5
3.9
4.3
4.6
4.9
5.3
5.8
6.6
7.6
9
Tab. I
kW = 7.8 mbar
= 2.2 mbar
= 10 mbar
20140036