Firing Rate; Procedure To Refer Burner Operating Condition In High Altitude Plants - Riello RS 50/E Installation, Use And Maintenance Instructions

3.8

Firing rate

The burner can work in two ways: low and high fire.
MAXIMUM OUTPUT must be selected in area A (Fig. 4).
MINIMUM OUTPUT must not be lower than the minimum limit
shown in the diagram.
Model MBtu/hr
RS 50/E 321
3.8.1 Procedure to refer burner operating condition
in high altitude plants
Find the CORRECTED BURNER CAPACITY for the plant's alti-
tude in chart 1 and the CORRECTED PRESSURE in chart 2.
Check in the firing rate graph of the burner (Fig. 4), if the working
point defined by the values above is within the range limits.
If not, higher burner size is needed.
Note
 Charts are based only on altitude variation (reference tem-
perature = 68 °F, 20 °C)
 To get the combined correction in case of different air tem-
perature, a compensation of 1000 ft each 20 °F (305 m each
11 °C) is applicable (100 ft = 2°F).
Example
Rated capacity = 1500 MBtu/hr - Rated air pressure = 1.5" WC
Real altitude = 3000 ft - Real temperature = 88 °F

= 88 °F - 68 °F (reference temp.) = 20 °F
(equivalent 1000 ft variation)
20 : 2 = 10 x 100 = 1000 ft
20053677
Technical description of the burner
kW
94
10
NOTE:
the firing rate areas given in Fig. 4 have been reduced by 10% with
respect to the maximum range that can be reached.
Consult procedure below to refer burner operating condition in high
altitude plants.
The firing rate area values have been obtained con-
sidering an ambient temperature of 68 °F, and an
atmospheric pressure of 394" WC and with the
WARNING combustion head adjusted as shown at page 19.
Proceeding as descripted above and considering a "virtual altitude"
of (3000 + 1000) ft:
– 1500 MBtu/hr at 4000 ft, the corrected capacity is 1713 MBtu/hr
– 1.5" WC at 4000 ft, the corrected burner air pressure is 1.71
Reference conditions:
– Ambient temperature 68 °F (20 °C)
– Barometric pressure 394" WC (1000 mbar)
– Altitude 328 ft a.s.l. (100 m a.s.l.).
D11846
Fig. 4