Riello RS 50 - Page 23

21
20144599
GB
Installation
Column 1
Combustion head pressure drop.
Gas pressure measured at test point 1) (Fig. 20), with:
• combustion chamber at 0 mbar;
• burner working at maximum output
Column 2
Pressure loss at gas butterfly valve 2)(Fig. 20) with maximum
opening: 90°.
Column 3
Train pressure drop 3) (Fig. 20) including: adjustment valve VR,
safety valve VS (both fully open), pressure adjuster R, filter F.
To calculate the approximate output at which the burner operates
in the 2nd stage:
– subtract the combustion chamber pressure from the gas
pressure measured at test point 1) (Fig. 20).
– Find in Tab. F related to the burner concerned, the pressure
value closest to the result of the subtraction.
– Read the corresponding output on the left.
Example - RS 28:
2nd stage operation
Natural gas G 20 NCV 10 kWh/Nm
3
Gas ring nut 2) (Fig. 13 on page 18) adjusted as per diagram
(Fig. 14 on page 18).
Gas pressure at test point 1) (Fig. 20) = 8.6 mbar
Pressure in combustion chamber = 2.0 mbar
8.6 - 2.0 = 6.6 mbar
A pressure of 6.6 mbar, column 1, corresponds in table
RS 28 to a 2nd stage output of 289 kW.
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 1) (Fig. 20),
set the maximum modulating output required from the burner
operation:
– find the nearest output value in the table Tab. F for the burner
in question.
– read, on the right (column 1), the pressure at the test point 1)
(Fig. 20).
– Add this value to the estimated pressure in combustion
chamber.
Example - RS 28:
Desired output in 2nd stage: 218 kW
Natural gas G 20 NCV 10 kWh/Nm3
Gas ring nut 2)(Fig. 13 on page 18) adjusted as per diagram
(Fig. 14 on page 18).
Gas pressure at an output of 218 kW = 4.3 mbar
Pressure in combustion chamber = 2.0 mbar
4.3 + 2.0 = 6.3 mbar
pressure required at test point 1)(Fig. 20).
Fig. 20
S9689