Principal Characteristics; Appliance Classification; Certification - Ec Marking; Functional Description - Accorroni MEC25-85 Technical Information

SECTION 1 - GENERAL INFORMATION

1. PRINCIPAL CHARACTERISTICS

1.1 APPLIANCE CLASSIFICATION

These appliance are defined as "Gas-fired air
heaters with an atmospheric burner equipped
with a fan in the combustion circuit".
In addition, they are classified according to
harmonised European standards EN 437 and
prEN 1020 into:
category - according to the types of gas, at the
different supply pressures, that they can use;
type - according to the possible methods to exhaust
the combustion productions (see also 4.3.1).
1) Category II
2H3+
the air heater is suitable to use gas that belongs
to two families. The atmospheric burner can be
fed with the gas from the second group (natural
gas - group H) and the gas from the third group
(butane and propane at the two pressure ratings
28-30 and 37 mbar)
2) Type C
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The combustion circuit is sealed with respect to
the environment in which it is installed and the
combustion air supply and combustion product
exhaust lines are connected outside the room by
means of ducts which pass directly through the
outside wall of the room, including terminals within
a square with a 50 cm side.
3) Type C
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The combustion circuit is hermetically sealed with
respect to the environment in which it is installed
and the combustion air supply and combustion
product exhaust lines are connected outside the
room by means of ducts with terminals located
also on walls not in the room. The combustion
products can be exhausted also with a special
duct on the roof of the building.
4) Type B
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Combustion air intake is performed within the
environment, while the combustion products are
exhausted through a duct that passes directly
through an external wall or on the roof of a
building.

1.2 CERTIFICATION - EC MARKING

The MEC air heaters, as previously described
and classified, have obtained the "CE type test
certificate" in conformity with EEC Directive 90/
396 and with reference to the harmonised
European standard prEN 1020. Attaching the CE
marking shown below also guarantees that the
appliance conforms with EEC directive 73/23
("Low voltage") and EEC directive 89/336
("Electromagnetic compatibility").

1.3 FUNCTIONAL DESCRIPTION

The MEC warm air heater consists basically of a
heat exchanger operating between the combustion
products of a gas burner and the air flow exerted
by one (models 25-30-35), two (models 50-57) or
three fans (model 85).
The air is drawn from the room by the fan(s),
conveyed to the exchanger which, operating to
the rated temperature by the burner, transfers
heat to the air.
With the MEC series appliances, the warm air is
inserted directly into the environment and the flow
can be directed using the louvers, while with the
MEC C series appliances, the warm air can be
distributed in the rooms by using special ducts
and delivery outlets.
Fan operation is controlled by a thermostat: to
prevent cold air from entering the environment,
the fan begins operating after the burner is ignited.
Instead, the fan is stopped with a short delay with
respect to when the burner is extinguished, to
allow the exchanger to cool off gradually.
In case of malfunction or if the fan(s) does(do) not
turn on and the exchanger overheats, a safety
thermostat trips and cuts off the gas flow to the
burner.
The combustion products are exhausted outdoors
by a centrifugal fan installed after the combustion
circuit. If the ducts are obstructed or the fan does
not work, a differential pressure switch cuts off the
gas flow to the burner.
Air heater operation can be controlled by a room
thermostat (not supplied) or from a remote-control
panel (supplied on request). With the remote-
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