35 / 69
000608042_200705
METHANE GAS IGNITION
AND ADJUSTMENT
1) Check that the combustion head
penetrates into the combustion
chamber to theextend required by
the boiler manufacturer . Check that
the device that closes the air at the
combustion head is presumable in
the position suited for the required
supply of fuel (the passage of air
between the disk and combustion
head must be significantly reduced ,
if in the opposite case the fuel supply
is rather high, the passage between
disk and combustion head must
be relatively open). See chapter
“Adjustment of combustion head”.
2) If it has not already been down when
connecting the burner to the gas
piping, it is essentially to vent the
air in the pipes, which should done
with doors and windows open. The
connector on the piping close to the
burner must be opened and then
the tap or taps that shut off the gas
must be opened a bit. Wait until you
can smell the gas and then close the
tap. Wait a sufficient length of time,
which will depending on the specific
conditions, until the gas in the room
disperses outside and then connect
up the burner again to the gas piping.
3) Check that there is water in the
boiler and that the system’s gate
valves are open.
4) Check very thoroughly that the
combustion products exhaust path
is free (boiler gates and flue open).
5) Check that current to be connected
corresponds with that required by
the burner and that the electrical
connections (motor and main line)
are set for the available power
supply. Check that all the electrical
connections carried out on site have
been correctly performed as in our
wiring diagram.
6) Apply a pressure gauge with suitable
scale to the gas pressure outlet to
check the set value (if the pressure
provided for permits it is preferable
to use a water column instrument
and not use those with pointers for
modest pressures).
7) Put the air adjustment electric
servo motor cams (see instructions
page.....) to the positions you
presume are suitable in proportion
to the minimum and maximum
modulation thermal flow and to the
ignition heat input.
8) Set the desired value for the ratio
between the gas and air pressures,
following the pneumatic valves
adjustment instructions given in the
manual provided with the gas train
installed
9) With the burner panel switch at the
“O” position and the main switch
on, check, by manually closing the
contactor, that the motor turns in the
correct direction, if necessary, swap
around the two power cables for
the three-phase motor to invert the
direction of rotation.
10) Now switch on the control panel
switch and turn the modulation
switches to MIN (minimum) and MAN
(manual). The control box is now
powered up and the programmer
sets the burner as described in the
chapter “description of working”.
Note: Preventilation is carried out
with air open and so the adjustment
servo motor is switched on performs
its complete opening run up to the set
“maximum”. Only when the adjustment
servo motor has returned to the “switch
on” position will the control box carry
out its ignition program, switching on
the transformer and gas valves for
ignition.
Check during preventilation that
the pressure switch that controls air
pressure in fact exchanges (from the
closed position where no pressure is
detected it must pass to the closed
position with air pressure detection).
If the air pressure switch does not
detect sufficient pressure (does not
carry out the exchange), the ignition
transformer does not switch on and
the valves for the ignition flame also
do not switch, with the result that the
control box goes to “lock-out”. It should
be pointed out that some “locking out”
during this phase of first switch on can
be regarded as normal because the
ramp valves piping will still have some
air in them and this must be eliminated
before a stable flame can be achieved.
To “release” the lock press the “release”
button.
On first switching on, repeated “lock
outs” may occur due to:
a) The gas piping not being freed of
the air sufficiently and so the gas
quantity is not enough to provide a
stable flame.
b) The “lock-out” with flame on may
be caused by flame instability in
ionisation area, due to incorrect
air-gas mix. This can be remedied
by varying the quantity of air and/
or gas until the right ratio is found.
The same problem may be caused
by incorrect air/gas distribution in
the combustion head. This can
be remedied with the combustion
head adjustment device by closing
or opening further the air passage
between combustion head and gas
diffuser.
11) Set the burner at minimum
thermal capacity of modulation
(air damper control servo motor
at minimum), check the size and
appearance of the flame, making
any necessary corrections. To do
this, follow the e instructions for the
pneumatic valves. Then carry out a
meter reading check on the quantity
of gas supplied. If necessary adjust
gas and combustion air supply as
described previously (points 7 and
8). Subsequently the combustion
is checked with the special
instruments. For the correct air-gas
mix, the carbon dioxide level must be
measured. (C02) for the methane is
at least 8% or O2=6% on minimum
burner supply up to a ideal value
of 10% or 02= 3% for maximum
supply. It is essential to check,
with a suitable instrument, that the
percentage of carbon monoxide
(CO) present in the fumes does not
exceed the limit set by regulations
at the time of installation.”
12) After adjusting the burner to
minimum thermal capacity, turn
the modulation switches to MAN
(manual) and MAX (maximum).
The servo motor that regulates the
air is put at “maximum” and so also
the gas supply reaches maximum
thermal capacity. A check must
then be carried out on the quantity
of gas supplied (by reading the
meter). With burner on at maximum
existing supply, the gas flow is
measured as the difference between
the two readings at exactly one
minute between one and the other.
Multiplying the value obtained by sixty
you obtain the flow in sixty minutes,
i.e. per hour. Multiplying the supply
per hour (m3/h) for the gas calorific
power you obtain the power supply
in kcal/h which must correspond to
or be very near to that required by
the boiler (lowest calorific power for
methane = 8550 kcal/h). You must
prevent the burner from continuing
to run if the flow is greater than the
maximum permitted for the boiler, to
avoid possible damage to the boiler
itself, and so the burner should be
stopped straight after the two meter
readings.
13) To change the maximum gas flow,
use the air flow regulator so that the
gas is suitably and automatically
adjusts itself to the supply of air.
The cam regulating the maximum
opening of the damper must be reset
(see instructions on adjustment
0002933650). The air damper
opening angle must be reduced to
reduce the gas flow and vice versa;
to change the gas-air mix see the
instructions for the pneumatic gas
valves installed.
14) Subsequently check the combustion
with the special instruments. For
a correct air-gas mix you must
measure the carbon dioxide (CO2)
to methane value and check that it is
