Unigas G400A - How to read the burner “Performance curve”; Checking the proper gas train size

PART I: SPECIFICATIONS
9
How to read the burner “Performance curve”
To check if the burner is suitable for the boiler to which it must be instal-
lled, the following parameters are needed:
 furnace input, in kW or kcal/h (kW = kcal/h/860);
 backpressure (data are available on the boiler ID plate or in the
user’s manual).
Example:
Furnace input: 600kW
Backpressure: 4 mbar
In the “Performance curve” diagram, draw a vertical line matching the
furnace input value and an horizontal line matching the backpressure
value. The burner is suitable if the intersection point A is inside the per-
formance curve.
Data are referred to standard conditions: atmospheric pressure at 1013
mbar, ambient temperature at 15° C.
Checking the proper gas train size
Performance Curves
To get the input in kcal/h, multiply value in kW by 860.
To check the proper gas train size, it is necessary to the available
gas pressure value upstream the burner’s gas valve. Then subtract
the backpressure. The result is called pgas. Draw a vertical line
matching the furnace input value (600kW, in the example), quoted
on the x-axis, as far as intercepitng the network pressure curve,
according to the installed gas train (DN65, in the example). From the
interception point, draw an horizontal line as far as matching, on the
y-axis, the value of pressure necessary to get the requested furnace
input. This value must be lower or equal to the pgas value, calcula-
ted before.
PRESSURE IN
COMBUSTION CHAMBER (mbar)
G258A M-
kW
G335A M-
kW
PRESSURE IN
COMBUSTION CHAMBER (mbar)
G380A M-
kW
G400A M-
kW
Campo di lavoro bruciatori
Tipo P60 Mod. M-xx.x.IT.A.0.50 - M-.xx.x.IT.A.0.65
-1
0
1
2
3
4
5
6
7
8
100 200 300 400 500 600 700 800 900
Potenza k W
Contropressione in camera di
combustione mbar
A
backpressure in
combustion chamber (mbar)
Power kW
0
5
10
15
20
25
100 200 300 400 500 600 700 800 900
Potenza / Output (kW)
Minima pressione gas in
rete / Minimum inlet gas
pressure (mbar)
Rp 2" (50)
DN65
Power kW
minimum gas pressure in
the network mbar
DN65