Publicidad
Idiomas disponibles
Idiomas disponibles
at least 8% or O2=6% with minimum
burner supply, up to an ideal value
of 10% or O2= 3% at maximum
supply. It is essential to check with
the correct instruments that the
percentage of carbon monoxide
CO present in the fumes does not
exceed the maximum permitted
value of 0.1 % (1000 p.p.m.)
15) after adjusting running at maximum
thermal capacity you have to set the
air adjustment servo motor at the
minimum supply position, turning
the modulation switch to MIN. If,
with burner running at minimum
power, it is necessary to change the
combustion conditions, follow the
pneumatic gas valves adjustment
devices' instructions. We advise you
carry out a check on combustion
with the special instruments and,
if necessary, change the setting
previously carried out, even on some
intermediate points on the course
set for the air damper.
16) now check the proper working of
the automatic modulation mode.
17) the air pressure switch is a
safety (lock-out) system for if the
air pressure is not that expected.
The pressure switch must therefore
be set to be triggered to close the
contact (it should be closed when
working) when the air pressure in
the burner reaches a suffi cient level.
Please note that if the contact which
should be closed when working
does not in fact close (air pressure
insuffi cient) the system goes through
its work cycle but does not switch
on the ignition transformer and the
gas valves will not open, with the
result that the burner stops in lock-
out. To check the right working of the
IONISATION CURRENT MEASUREMENT
To measure the ionisation
current, remove the jumper
between terminals 30-31 on the
printed circuit with the burner
off (see diagram). Connect a
microampmeter to the terminals
(with a suitable scale to have the
burner restart). Once the fl ame
has appeared it will be possible
to measure the ionisation current,
the minimum value of which
to ensure the working of the
equipment is shown in the specifi c
wiring diagram. After making the
measurement, reset the jumper
that has been disconnected.
air pressure switch you must, with
burner at minimum supply, increase
regulation to check the triggering that
leads to immediate "lock-out" of the
burner. To release the locked burner,
press the release button and reset the
pressure switch to a value suffi cient
to detect the existing air pressure
during the preventilation stage. The
pressure switch's connection circuit
has automatic control so the contact
must be closed at rest (fan stopped
and so no air pressure in burner).
This condition is produced if
control box is not switched on and
the burner stays stopped.
18) The gas pressure control switches
(minimum
and
maximum),
installed, prevent the working of the
burner when the gas pressure is
not within the preset values. From
the specifi c function of the pressure
switches it is clear that the minimum
pressure control switch must use
the contact that is closed when the
pressure switch detects a pressure
greater than that set, while the
maximum pressure switch must use
the contact which is closed when
the
pressure switch detects
pressure that is lower than that set.
The adjustment of the minimum
and maximum gas pressure gas
switches must therefore take place
on inspection and testing of the
burner according to the pressure
from time to time found. The pressure
switches are electrically connected
in series, thus the triggering (i.e. with
circuit opening) any one of the gas
pressure switches, which prevents
the switching on the control box and
hence of the burner. When the burner
is running (fl ame on), the triggering
38 / 72
0006081042 - ed2006/06
of thegas pressure switches (circuit
opening) causes the immediate
stoppage of the burner. When the
burner is being tested it is essential
to check the proper working of
the
pressure switches. Using the
respective adjustment devices, the
triggering of the pressure switch
(circuit opening) can be checked,
ensuring it causes the arrest of the
burner.
19) Check the fl ame sensor (ionisation
sensor) is triggered, disconnecting
the
the bridge between terminals 30
and 31 on the printed circuit and
switching on the burner. The control
box
must completely carry out its
if
working cycle and, three seconds
after the ignition fl ame is formed,
stop itself in "lock-out". This check
only needs to be carried out with the
burner already on. Disconnecting
the 30 and 31 jumper, the control
box must immediately go into its
"lock-out" action.
20) Check the proper working of the
thermostats or pressure switches for
the boiler (when triggered they must
stop the burner.
a
N.B. Check that the switch on occurs
normally since if the adjuster is shifted
forward, it may happen that the speed
of the delivery air is so high that ignition
is diffi cult. If this happens, the adjust
must be shifted back by degrees until it
is in a position in which ignition occurs
normally, and this new position can
be regarded as the fi nal position. We
remind you that is preferable, in the
case of the small fl ame, to limit the
quantity of air to the least possible
needed for safe ignition, even in the
most diffi cult circumstances.
N°0002934790
N°0002934790
REV.: ------------
REV.: ------------
Publicidad
