4.12.4 Gas Pressure - Riello RS 68/EV O2 ULX Installation, Use And Maintenance Instructions

4.12.4 Gas pressure

Each diagram indicate the minimum pressure drops depending
on the maximum burner output.
The values shown, refer to:
– Natural gas G 20 NCV 9.45 kWh/Sm
Calculate the approximate output of the burner in this way:
– subtract the combustion chamber pressure from the gas
pressure measured at test point 20)(Fig. 7 on page 12).
– Enter the mbar scale (Fig. 25, Fig. 26, Fig. 27 and Fig. 28)
and read the corresponding output by reading on the line.
Example RS 120/EV O2 ULX with G20 natural gas:
Fixed Output operation
Gas pressure at test point P1
Pressure in combustion chamber
A pressure of 30 mbar, corresponds to an output of 750 kW with
factory setting for central gas.
Installation
3
= 35 mbar
= 5 mbar
35 - 5 = 30 mbar
27 GB
Example RS 200/EV O2 ULX with G20 natural gas:
Fixed Output operation
Gas pressure at test point P1
Pressure in combustion chamber
A pressure of 100 mbar, corresponds to an output of 1750 kW
with factory setting for central gas.
This value serves as a rough guide; the effective output must be
measured at the gas meter.
To calculate the required gas pressure at test point 20)(Fig. 7 on
page 12) set the MAX output required from the burner operation:
– find the nearest output value (Fig. 25, Fig. 26, Fig. 27 and
Fig. 28).
– Read the pressure at the test point 20)(Fig. 7 on page 12).
– Add this value to the estimated pressure in the combustion
chamber.
Example for RS 120/EV O2 ULX with G20 natural gas:
Required burner maximum output operation: 750 kW
Gas pressure at an output of 750 kW
Pressure in combustion chamber
Pressure required at test point 20)(Fig. 7 on page 12).
Example for RS 200/EV O2 ULX with G20 natural gas:
Required burner maximum output operation: 1750 kW
Gas pressure at an output of 1750 kW with
factory setting for central gas regulation
Pressure in combustion chamber
Pressure required at test point 20)(Fig. 7 on page 12).
The output and gas pressure data refer to op-
eration with gas butterfly valve fully open (90°)
on the whole firing rate.
WARNING
= 108 mbar
= 8 mbar
108 - 8 = 100 mbar
= 30 mbar
= 5 mbar
35 + 5 = 35 mbar
= 100 mbar
= 8 mbar
100 + 8 = 108 mbar
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