B
LB 429
Blu 170 ÷ 350 P /P AB
pag.16
STARTUP OF THE BURNER
PRELIMINARY CHECKS
Before starting up the boiler check the following:
• gas type and feed pressure;
• gas valves closed;
• the seals in the pipe fittings;
• gas pipe breather and input pressure;
• that the cable complies with the diagram and the phase and neutral wires correspond;
• that the burner shuts down when the boiler thermostat opens
• the seal of the boiler furnace which prevents air from entering
• the seal on the flue-boiler pipe fitting;
• the condition of the flue (sealed, free from blockage, etc.).
If all these conditions are present, start the burner.
The control device starts the motor to carry out prewashing of the combustion chamber.
During this prewash period (about 30 seconds) the device checks that air pressure is correct via the air pressu-
re switch.
At the end, it supplies power to the transformer and opens the gas valves.
The flame must be lit and stabilize within 3 seconds, which is the device's safety time limit.
Check to ensure the flame is lit before placing any control instrument in the flue.
Adjust and check the gas flow necessary for the boiler at the meter.
Adjust the air flow according to the gas flow to obtain correct combustion.
IMPORTANT ADVICE
All adjustable parts must be fixed by the installer after making adjustments.
Check flue combustion after each adjustment.
The CO
2
values must be approx. 9.7 (G20) 9.6 (G25 11.7 (l3B) 11.7 (l3P) and the CO must be less than 75
ppm.
Adjusting the gas flow rate at the ignition for burners BLU 170/BLU 250/BLU 350
The thermal power at the ignition, for such a burners, must be smaller than 120 kW or else than the ratio between the rated ther-
mal power and control box’s safety time (ignition time is assumed equal to safety time, i.e. 3 seconds). The adjustment of thermal
power at the ignition is made by the manufacturer, anyhow, should it be necessary to intervene on such an adjustment, proceed as
follows: - check that the thermal power of the burner at full running is the correct one. - With the burner switched off, disconnect
the flame detection cable from relevant electrode, so as to make the valve to automatically shut off at the ignition, after the safety
time. - Make a reading on the gas meter. - Start the burner and wait for the burner’s lock out,
after the repetition of the ignition sequence. - Make a second reading on the meter, and note the
number of delivered litres. - The delivered thermal power, at the ignition, will then be equal to
the ratio, between the delivered litres and the safety time, multiplied by the F factor (as function
of the type of gas used) read on the table at the side. If the value thus obtained is higher than 120
kW it shall be necessary to reduce the gas valve’s initial flow rate. At the end, reconnect the flame
detection cable to its relevant electrode.
NOTE:
should it be difficult to measure the quantity of delivered litres of gas, due to the particular meter’s dial, it is possible to
repeat, sequentially, the above steps many times, so as to reach a significant amount of gas volume. In such a case, the thermal
power at the ignition shall be obtained by multiplying the ratio, between the amount of delivered litres and the number of cumula-
ted safety times (i.e. the value of the safety time multiplied by the number of ignitions) by the F factor. See the following examples:
Example A: BLU 350 burner, nat. gas; rated thermal power 350 kW; safety time of 3 secs; delivered gas volume during safety time
= 12 l: The ignition thermal power, in kW, shall be: 12/3*34,02 = 136 kW. In such a case, it will be necessary to reduce the ther-
mal power at the ignition by acting on the suitable adjusting screw, until reaching a thermal power smaller than 120 kW.
Example B: BLU 170 burner, nat. gas; rated thermal power of 179 kW; safety time of 3 secs; a sequence of 4 ignitions is made, for
a total amount of 41 delivered litres. The thermal power at the ignition, in kW, shall be: 41/(3*4)*34,02 = 116 kW and therefore
correct, being smaller than 120 kW.
GAS
F
G20 (nat.gas) 34,02
G25
-
G30 (buthane) -
G31 (propane) 88
