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SECTION 1 - GENERAL INFORMATION
certificate” in conformity with EEC Directive 90/
396 and with reference to the harmonised
EuropeanstandardprEN1020.AttachingtheCE
marking shown below also guarantees that the
appliance conforms with EEC directive 73/23
(“Low voltage”) and EEC directive 89/336
(“Electromagneticcompatibility”).
1.3FUNCTIONALDESCRIPTION
TheMECwarmairheaterconsistsbasicallyofa
heatexchangeroperatingbetweenthecombustion
productsofagasburnerandtheairflowexerted
byone(models25-30-35),two(models50-57)or
threefans(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.
WiththeMEC series appliances, thewarm air is
inserteddirectlyintotheenvironmentandtheflow
canbedirected using thelouvers,while with the
MEC C series appliances, the warm air can be
distributed in the rooms by using special ducts
anddeliveryoutlets.
Fan operation is controlled by a thermostat: to
prevent cold air from entering the environment,
thefanbeginsoperatingaftertheburnerisignited.
Instead,thefanisstoppedwithashortdelaywith
respect to when the burner is extinguished, to
allow the exchanger to cool off gradually.
Incaseofmalfunctionorifthefan(s)does(do)not
turn on and the exchanger overheats, a safety
thermostat trips and cuts off the gas flow to the
burner.
Thecombustionproductsareexhaustedoutdoors
byacentrifugalfaninstalledafterthecombustion
circuit.Iftheductsareobstructedorthefandoes
notwork,adifferentialpressureswitchcutsoffthe
gas flow to the burner.
Airheateroperationcanbecontrolledbyaroom
thermostat(notsupplied)orfromaremote-control
panel (supplied on request). With the remote-
1. PRINCIPAL CHARACTERISTICS
1.1APPLIANCECLASSIFICATION
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-accordingtothepossiblemethodstoexhaust
thecombustionproductions(seealso4.3.1).
1) Category II2H3+
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
(butaneandpropaneatthetwopressureratings
28-30and 37mbar)
2) Type C12
The combustion circuit is sealed with respect to
the environment in which it is installed and the
combustion air supply and combustion product
exhaustlinesareconnectedoutsidetheroomby
means of ducts which pass directly through the
outsidewalloftheroom,includingterminalswithin
a square with a 50 cm side.
3) Type C52
Thecombustioncircuitishermeticallysealedwith
respecttotheenvironmentinwhichitisinstalled
and the combustion air supply and combustion
productexhaustlinesareconnectedoutsidethe
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 B22
Combustion air intake is performed within the
environment,whilethecombustionproductsare
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
