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2.
CONTROL AND SAFETY DEVICES
2.1 GAS CONTROLLER
This device is housed in a heat-resistant and
shockproof plastic enclosure and is mounted on
the air heater electric board (fig. 7). The control
device operates on the ionisation flame detection
principle, using a special probe on the burner.
The detection circuit must be fed with single-
phase 230 V ~ 50 Hz mains voltage. The
circuit is sensitive to the phase-neutral
polarity. If this is reversed, the device will
lock out within the safety time, even if the
flame has a regular shape.
2.2 GAS VALVE
The gas valve includes two, direct operation
solenoid valves with class B closing devices
(maximum pressure 50 mbar) and a pressure
regulator. The die-cast aluminium casing is
equipped with 3/8 RP threaded gas inlet and
outlet connections and two inlet and outlet
pressure test points. The gas valve is also
equipped with an inlet filter (fig. 8).
2.3 DIFFERENTIAL PRESSURE SWITCH
The purpose of this device is to interrupt the
burner’s functioning if the flue gas expeller fan’s
capacity is insufficient due to a problem with the
fan or due to the obstruction of the combustion
circuit.
The pressure switch is mounted on the
generator’s electrical board and is connected to
a pressure intake on the exchanger by means of
a silicone tube so that it can measure the pressure
differential in the combustion circuit. There is an
Fig. 7
CONTROL EQUIPMENT
Fig. 9
Sealed adjustment screw
DIFFERENTIAL PRESSURE SWITCH
Fig. 10
FAN THERMOSTAT
Threaded fastener
Electrical connection
Fig. 8
GAS UNIT
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room. The air flow must not be obstructed by
objects such as internal dividers, shelves,
furniture, or drapes.
f) For air delivery via ducts (WD):
The selected position must permit the ducts
to follow a rational path which keeps pressure
drops to a minimum and allows the ducts to
be inspected.
4.1.1 Versions for ceiling installation
(WR and WD)
The unit must be installed only in a horizontal
position. For the WR version make sure that
there is a distance of approximately 20 cm
between the rear part of the unit and the wall so
as to permit correct air intake and to allow the
filter to easily be removed for cleaning (fig. 13).
For the WD version make sure that the air intake
system (dampers, plenum systems, ducts, etc.)
is accessible and functional.
IMPORTANT! Verify that the carrying capacity
of the surface on which the unit is to be
mounted and this surface’s material are
suitable for supporting the weight of the unit.
Make sure that the materials used to attach
the unit guarantee its lasting stability.
4.1.2 Version to be installed on the wall (W)
The unit should be placed on the wall with its
lower side at least 20 cm above the floor to allow
proper air intake. It the unit is to be installed
under a window or under a shelf, make sure that
the window sill or the shelf does not obstruct
the air flow (fig.14).
4.2 AIR INTAKE AND FLUE EXHAUST DUCTS
WARNING! The material used to build the
external wall and any covering (wood, plastic)
must not be sensitive to the heat generated
by the flue gas exhaust duct. If it is heat
sensitive, the passage hole must be protected
with insulation that insulates the wall or the
covering.
4.2.1 Type definition
As already mentioned in point 1.1, the W, WR,
and WD air heaters can be installed with different
configurations of the air intake and combustion
product exhaust ducts and these different
solutions constitute the definition of “type”
according to the current standards (fig.15):
- Type C
12
The combustion circuit is sealed with respect to
the room in which the air heater is installed. The
intake and exhaust ducts pass directly through
the room’s outside wall; their terminals are near
each other.
- Type C
52
The combustion circuit is sealed with respect to
the environment in which the air heater is installed.
The ducts are both connected to the outdoors,
but their terminals need not be adjacent to each
other.
IMPORTANT! in both these instances the
exhaust and intake ducts, including their
accessories, are considered to be integral
parts of the air heater by current regulations.
Therefore, if you wish to add any components
Fig. 12
60 cm
30 cm
30 cm
60 cm
max. 3 m
MINIMUM DISTANCES FOR MAINTENANCE
INSTALLATION
ON THE WALL
View from above
INSTALLATION ON THE CEILING - Front view
Summary of Contents for W
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