15
BURNER CALIBRATION
The optimum calibration of the burner requires
an analysis of the flue gases at the boiler outlet.
Adjust successively:
1 - First firing output
2 - 1st stage burner output
3 - 2nd stage burner output
4 - Air pressure switch
5 - Maximum gas pressure switch
6 - Minimum gas pressure switch
1 - FIRING OUTPUT
According to EN 676 Regulations:
Burners with max. output up to 120 kW
Firing can be performed at the maximum opera-
tion output level. Example:
• Max. operation output
: 120 kW
• Max. firing output
: 120 kW
Burners with max. output above 120 kW
Firing must be performed at a lower output than
the max. operation output. If the firing output
does not exceed 120 kW, no calculations are
required. If firing output exceeds 120 kW, the
regulations prescribe that the value be defined
according to the control box safety time "ts":
• for "ts" = 2s, firing output must be equal to or
lower than 1/2 of max. operation output.
• For "ts" = 3s, firing output must be equal to or
lower than 1/3 of max. operation output.
Example:
MAX operation output of 600 kW.
Firing output must be equal to or lower than:
• 300 kW with "ts" = 2s
• 200 kW with "ts" = 3s
In order to measure the firing output:
- Disconnect the plug-socket 18)(A)p.5 on the
ionization probe cable (the burner will fire and
then go into lock-out after the safety time has
elapsed).
- Perform 10 firings with consecutive lock-outs.
- On the meter read the quantity of gas burned.
This quantity must be equal to or lower than the
quantity given by the formula:
Example
for G 20 gas (10 kWh/Nm
3
):
Max. operation output: 600 kW corresponding to
60 Nm
3
/h.
After 10 firings with lock-outs, the delivery read
on the meter must be equal to or lower than:
60 : 360 = 0,166 Nm
3
.
2 - 1ST STAGE OUTPUT
MIN gas setting
Measure gas delivery at the meter.
- If it is to be reduced, close the 1st stage gas
valve a little.
- If it is to be increased, first open the 1st stage
gas valve all the way and then, if it is not
enough, increase the gas pressure coming
from the pressure governor.
MIN air setting
Operate the orange lever of the servomotor to
optimize the ratio between the quantity of air and
gas.
This is particularly important when the burner is
set for two stage operation.
Then close load control TR, or insert the jumper.
The servomotor will complete the rotation by
opening the air gate valve and the stage 2 gas
valve.
There must be no jerks or pulsations in the pas-
sage from stage 1 to stage 2.
Nm
3
/h
(max. burner delivery
)
360
Summary of Contents for GAS 9/2
Page 2: ......
