Calc Function; Burner Adjustment - Riello 896 T Installation, Use And Maintenance Instructions

Start-up, calibration and operation of the burner
5
5.9

CALC function

100
90
80
original
70
curve
60
50
40
30
20 CALC-
10
0
P0 P1 P2 P3 P4
Point of the curve
The diagram of Fig. 35 shows how the fuel modulation curve is
modified if the values of point "P5" are changed.
By keeping the key "+" pressed for more than 3 s, the points
from "P6" to "P8" are recalculated.
By keeping the key "-" pressed for more than 3 s, the points from
"P4" to "P2" are recalculated.

5.10 Burner adjustment

Output upon ignition
According to the regulation EN 676.
Burners with MAX output up to 120 kW
Ignition can be performed at the maximum operation output
level. Example:
max. operation output:

max. output upon ignition:

Burners with MAX output above 120 kW
Ignition must be performed at a lower output than the max. oper-
ation output.
If ignition output does not exceed 120 kW, no calculations are
required. If ignition output exceeds 120 kW, the regulations pre-
scribe that the value be defined according to the control box
safety time "ts":
for "ts" = 3s, ignition output must be equal to, or lower than, 1/3
of max. operation output.
Example
MAX operation output of 450 kW.
The ignition output must be equal to, or less than, 150 kW with
ts = 3s
In order to measure the ignition output:
disconnect the plug-socket 6)(Fig. 5) on the ionisation probe

cable (the burner will fire and then go into lockout after the
safety time has elapsed);
perform 10 ignitions with consecutive lockouts;

on the meter, read the quantity of gas burned:

this quantity must be equal to, or lower than, the quantity
given by the formula, for ts = 3s:
Qa (max. burner delivery) x n x ts
Vg =
Vg: volume supplied in ignitions carried out (Sm
3
Qa: ignition delivery (Sm
/h)
n: number of ignitions (10)
ts: safety time (sec)
20022445
D7908
CALC+
Recalculation
P5 P6 P7 P8 P9
Fig. 35
120 kW
120 kW
3600
3
)
100
90
80
70
60
50
40
30
20
10
0
P0 P1
The diagram of Fig. 36 shows the fuel modulation curve
when, after the modification of point "P5", the recalculation
of all the other points is not carried out.
Example for gas G 20 (9.45 kWh/Sm
ignition output 150 kW
corresponding to 15.87 Sm
After 10 ignitions with lockout, the delivery indicated on the
meter must be equal to, or less
15.87 x 10 x 3
Vg =
Maximum output
The MAX output must be set within the firing rate of Fig. 3.
Gas adjustment
Measure the gas delivery on the meter.
As a general rule, this value can be found on the table on page
52: just read the gas pressure on the pressure gauge (Fig. 38)
and follow the indications given on page 52.
If it is necessary to reduce it, lower the output gas pressure

via the pressure adjuster located beneath the gas valve.
If it needs to be increased, increase the output gas pressure

via the adjuster.
Air adjustment
If necessary vary the degrees of the air servomotor.
Minimum output
The MIN output must be set within the firing rate of Fig. 3.
32
GB
P2 P3 P4 P5 P6 P7 P8
Point of the curve
3
):
3
/h.
than:
3
= 0.132 Sm
3600
D7909
P9
Fig. 36