Gas Train; Gas Pressure - Riello RS5 Installation, Use And Maintenance Instructions

5.9.3

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.
5.9.4

Gas pressure

Tab. J 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. J 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. 15), 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. 15).
- Find, in Tab. J related to the burner concerned, the pressure
value closest to the result of the subtraction.
- Read the corresponding output on the left.
Example with natural gas G 20 for RS5:
Maximum output operation
Pressure of the gas at test point M2)(Fig. 15)
Pressure in combustion chamber
12.2 - 2.2
A pressure of 10 mbar, column 1, corresponds in the table Tab. J
to an output of 330 kW.
This value serves as a rough guide; the effective output must be
measured at the gas meter.
20198379
Installation
3 3
(8.2 Mcal/Sm )
3 3
(7.0 Mcal/Sm )
= 12.2mbar
= 2.2 mbar
= 10 mbar
20 GB
kW
G 20
160 3
179 3.6
198 4.3
217 5
236 5.8
254 6.5
273 7.4
292 8.2
311 9.1
330 10
The data of thermal output and combustion
head gas pressure are related to full open (90°)
gas butterfly valve.
WARNING
To calculate the required gas pressure at test point M2)(Fig. 15),
with the maximum modulating output at which you want the burn-
er to operate having been fixed:
- find the nearest output value in the table Tab. J for the burner
in question.
- Read on the right, column 1, the pressure at the socket
M2)(Fig. 15).
- Add this value to the estimated pressure in combustion
chamber.
Example with natural gas G 20 for RS5:
Operating at the desired maximum output: 330 kW
Gas pressure at an output of 330 kW
Pressure in combustion chamber
10 + 2.2
pressure required at the test point M2)(Fig. 15).
p (mbar)
G 25 G 31
4.2 4
5 4.4
6 4.8
7 5.4
8.1 6
9.1 6.7
10.4 7.5
11.5 8.4
12.7 9.4
14 10.5
Tab. J
= 10 mbar
= 2.2 mbar
= 12.2 mbar