Firing Rates - Riello GAS 3 P/M Installation, Use And Maintenance Instructions

4.8

Firing rates

During operation, burner output varies between:
– MINIMUM OUTPUT in 1st stage
– MAXIMUM OUTPUT in 2nd stage
 The MINIMUM OUTPUT (MIN) is to be chosen from within
the range of values indicated on diagrams.
Example:
for GAS 3 P/M, it can be chosen from 80 and 175 kW (equivalent
to 69 and 150 Mcal/h)
It is not required to know the pressure in combustion chamber in
1st stage.
 The MAXIMUM OUTPUT (MAX) is to be chosen from within
the diagram area on the side. This area is known as FIRING
RATE and provides the burner maximum output according to
the pressure in the combustion chamber. The work point is
found by drawing a vertical line from the required output and
an horizontal line from the corresponding pressure in the
combustion chamber. The intersection point of the two lines
is the work point, which must fall within the FIRING RATE.
Example:
for GAS 3 P/M the area is delimited by:
– 130 - 135 kW output axis
– axis of pressures in comb. chamber 0 + 7 mbar
– combustion chamber maximum pressure curve.
If the burner output is 250 kW at a pressure of 5 mbar in the
combustion chamber, the work point is on the maximum pressure
curve.
This curve has been set with safety margins, so that all the
FIRING RATE area can be used.
The firing rate value (Fig. 3) has been obtained
considering an ambient temperature of 20 °C, an
atmospheric pressure of 1013 mbar (approx. 0 m
a.s.l.), and with the combustion head adjusted as
ATTENTION
shown on pag. 20.
The burner output to be matched with the boiler is to be chosen
from the MAX area, namely from the FIRING RATE.
The burner can operate also in depressurised combustion
chambers.
GAS 3 P/M
Thermal power - kW
Technical description of the burner
S9729
Fig. 2
11 GB
GAS 4 P/M
Thermal power - kW
GAS 5 P/M
Thermal power - kW
GAS 6 P/M
Thermal power - kW
GAS 7 P/M
Thermal power - kW
S9730
S9731
S9732
S9733
Fig. 3
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