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5)
The burner is equipped by a device which allows to set combustion at best by reducing or increasing the air
passage between disc and head.
The maximum allowed smokes’ intensity is n° 2 of Bacharach scale, with a carbon diaxide value (CO
2
) between
n° 10 ÷ 13 %.
As a rule it’s necessary to reduce the air passage between disc and head when the burner operates with a
reduced fuel delivery; this passage must be proportionally more opened when the burner operates with an higher
fuel delivery. When this position has been changed, it’s necessary to check that ignition occurs cerrectly.
NATURAL GAS IGNITION AND ADJUSTMENT (METHANE)
Note : Please refer to the last pages where specific instructions are given with regard to regulating the gas delivery in
function with the type of valve fitted on the burner.
Before firing it’s indispensable to make the air purge from the pipes and check, if the burner is a three-phase one, that the
rotation sense is correct.
After this, da as follows:
1)
Make sure that the combustion product’s discharge may take place freely (chimney gate open) and that there
is water in the boiler.
2)
Open of the necessary quantity the combustion air regulator and open of 1/3 about the air passage between
head and disc acting accordingly on the regulating screw of the flame disc.
3)
Act on the regulators joint to the gas valves so as to allow the necessary gas delivery.
Note : Please refer to the last pages where specific instructions are given with regard to regulating the gas
delivery in function with the type of valve fitted on the burner.
4)
Energize the burner connecting the main switch and the burner switch.
The burner thus is connected and makes the prewashing phase.
If the control pressure switch of the air pressure detects a pressure higher then the value to which it’s
adjusted, the ignition transformer connects and further to this also the gas valves.
The safety valve opens completely while the main valve, which includes the regulation devices, opens in two
times. The first opening time makes the starting capacity and happens at once.
The second opening time happens slowly and at its end, the burner is in the maximum capacity allowed by the
position in which the maximum capacity adjuster has been positioned.
During the first ignition some “clampings” may happen due to following reason:
a)
The gas line has not been purged by the air sufficiently and therefore the gas quantity can’t grant a
stable flame.
b)
Clamping with flame on, can be caused by instability of the same, owing to a wrong ratio air/gas.
This can be remedied by varvying the quantity of air and/or gas delivered so as to find the correct ratio.
The same problem can be caused by a wrong delivery air/gas in the combustion head.
This can be remedied by acting on the combustion head regulation device by closing (pull back) or by
opening (move forward) the air passage between head and gas diffuser.
This can be done by acting on the regulation screw of the flame disc.
5)
With burner operating adjust the delivery at the value corresponding to the desired capacity (natural gas = 8550
kcal/m
3
) reading on the counter. This capacity can be modified by acting on the relative regulator included in the
valve, as above exposed.
6)
Check that combustion happens correctly, through the suitable instruments.
Maximum value admitted of carbonic axide (CO) = 0,1% with carbon dioxide (CO
2
) value between 8 ÷ 10 %.
7)
After having done the regulation it’s necessary to switch off and on the burner times so as to verify that ignition
occurs correctly.
