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5.10.4 Gas pressure
Tab. O indicates the pressure drop of the combustion head and
the gas butterfly valve depending on the operating output of the
burner.
1 p (mbar)
kW
G 20
930
5,6
1100
7,5
1300
9,7
1600
13,0
1860
17,7
1383
9,0
1500
10,7
1800
14,7
2100
20,3
2400
28,0
The values shown in Tab. O refer to:
–
Natural gas G 20 NCV 9.45 kWh/Sm
–
Natural gas G 25 NCV 8.13 kWh/Sm
Column 1
Load loss at combustion head.
Gas pressure measured at the test point 1)(Fig. 25), with:
•
combustion chamber at 0 mbar;
•
burner working at maximum output;
Column 2
Pressure loss at gas butterfly valve 2)(Fig. 25) 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. 25).
–
Find, in the Tab. O relating to the burner concerned, column
1, the pressure value closest to the result you want.
–
Read the corresponding output on the left.
Example with natural gas G 20 for RS 200/EV O
Maximum output operation
Gas pressure at test point 1)(Fig. 25)
Pressure in combustion chamber
23.3 - 3.0
A maximum output of 2100 kW shown in Tab. O corresponds to
20.3 mbar pressure, column 1.
This value serves as a rough guide; the effective output must be
measured at the gas meter.
To know the required gas pressure at test point 1)(Fig. 25), set
the maximum output required from the burner operation, then:
–
find the nearest output value in the Tab. O for the burner in
question.
–
Read, on the right (column 1) the socket pressure 1)(Fig. 25).
–
Add this value to the estimated pressure in the combustion
chamber.
Installation
2 p (mbar)
G 25
G 20
G 25
8,4
0,0
0,0
11,2
0,0
0,0
14,5
0,8
1,2
19,4
3,0
4,5
26,4
3,8
5,7
13,4
3,1
4,7
16,0
3,7
5,5
21,9
5,3
7,9
30,3
7,2
10,7
41,8
9,4
14,0
Tab. O
3
3
(8.2 Mcal/Sm
)
3
(7.0 Mcal/Sm
3
)
BLU:
2
=
23.3 mbar
=
3.0 mbar
=
20.3 mbar
Example with natural gas G 20 for RRS 200/EV O
Required burner maximum output operation: 2100 kW
Gas pressure at output of 2100 kW
Pressure in combustion chamber
pressure required at test point 1)(Fig. 25).
S8716
The heat output and gas pressure data in the
head refer to operation with gas butterfly valve
fully open (90°).
WARNING
27
GB
=
=
20.3 + 3.0
=
BLU:
2
20.3 mbar
3.0 mbar
23.3 mbar
Fig. 25
20156417
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