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Idiomas disponibles
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The minimum value of the
ionization current to ensure the
working of the control box is
shown on the specific electrical
diagram.
8) With the burner lighted to the mi-
nimum, it is necessary to visually
check the entity and appearance
of the flame immediately, and
make the necessary corrections
by adjusting the gas and air
supply regulators (see points 4
and 5). Subsequently, read the
meter to check the quantity of gas
supplied. If necessary, correct
the gas and combustion air sup-
ply by proceeding as described
above (points 4 and 5). Then
check the combustion using the
special instruments provided for
the purpose. For a correct gas/air
ratio, the carbon dioxide (CO2)
value for methane must be at
least 8%, or O2 = 6% at minimum
supply to the burner, up to an
optimum value of 10% or O2 =
3% for maximum supply.
It is essential to check the per-
centage of carbon monoxide (CO)
present in the fumes, to ensure
that it does not exceed the ma-
ximum permitted value of 0.1%
(1000 ppm).
9) Repeatedly check that the first fla-
me is correctly supplied with gas
after adjustment of first flame wor-
king, switch off the burner with the
master switch (1); select switch
(3) on the 2nd stage symbol and
also make a "bridge" between
the corresponding terminals or
connect the 2nd stage thermostat
(1st and 2nd stage switch must be
in 2nd stage position).
10) Open the gas flow manual regu-
lator to the extent necessary for
the second stage.
11) Now switch the burner back on,
closing the master switch (1).
The burner ignites and the 2nd
stage automatically switches on.
Carry out an immediate visual
check on the extent of and appe-
arance of the flame, performing
the necessary corrections with
the gas and air supply regulators
as indicated in points 4 and 5.
12) Adjust the flow regulator suitably
for the second flame to suit the
specific case. Avoid keeping the
burner in operation if the flow
rate is greater than the maximum
value permitted for the boiler. To
prevent possible damage to it, it
is therefore advisable to switch off
the burner immediately after two
meter readings.
13) Subsequently, with the burner at
the maximum supply required for
the burner, check the combustion
using the instruments provided,
and modify, if necessary, the
adjustment made earlier (air, and
gas, if necessary) by means of
visually checking only (CO2 max.
= 10%; O2 min. = 3%; CO max.
= 0.1%).
14) The air pressure switch has the
function of preventing opening of
the gas valve if the air pressure
is incorrect. The pressure switch
must therefore be adjusted to
operate by closing the contact
when the pressure of air in the
burner reaches a sufficient value.
The connecting circuit of the pres-
sure switch involves self-control;
therefore, it is necessary that the
contact provided for closing with
the fan stopped (absence of air
pressure in the burner) actually
brings about this condition. Other-
wise the control box is not activa-
ted (the burner remains stopped).
If the air pressure switch does
not measure a pressure higher
than the calibration value, the
equipment performs its cycle,
but does not activate the ignition
transformer and the gas valves do
not open; therefore, the burner is
stopped by "lock-out". To ensure
correct working of the air pressure
switch, it is necessary to increa-
se the regulation value, with the
burner lighted, with only the first
flame, resulting in the action that
will be immediately followed by
the burner stopping in "lock-out".
Release the burner, pressing the
release button and adjust the
pressure switch to half the level
of the air pressure detected by the
pressure in stage 1.
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0006081054_200810
15) The gas pressure control
switches (minimum and ma-
ximum) have the function of
preventing the burner from fun-
ctioning when the air pressure
is not within the required values.
From the specific function of the
pressure switches, it is quite clear
that the minimum pressure con-
trol switch must use the contact
that is closed when the pressure
switch measures a pressure
higher than that for which it is
adjusted. The maximum pressure
switch must use the contact that is
closed when the pressure switch
measures a pressure lower than
the one for which it is adjusted.
Regulation of the minimum and
maximum pressure switches must
therefore occur when the burner
starts operating depending on the
pressure encountered every so
often. The pressure switches are
electrically connected in series;
therefore the action (understood
as opening of the circuit) of the
gas pressure switches does not
allow the appliance to be activa-
ted. It must be specified that the
action (understood as opening of
the circuit) of any one of the pres-
sure switches, when the burner is
operating (flame on) immediately
causes the burner to stop. On first
ignition of the burner, it is essen-
tial to check that the pressure
switches are working correctly.
The respective regulation controls
can be used to check the action
of the pressure switch (opening
of the circuit) which causes the
burner to stop.
16) Check the action of the flame
detector (ionization electrode)
by disconnecting the wire from
the electrode and activating the
burner. The appliance must per-
form its cycle completely and,
three seconds after the ignition
flame appears, it must stop in
"lock-out". This check must also
be carried out with the burner
already switched on. On discon-
necting the wire from the ioniza-
tion electrode, the appliance must
immediately go into "lock-out".
The appliance can only be re-
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