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3. GENERAL FEATURES
3.1 DESCRIPTION OF OPERATION
The MEC MIX COND is classified as individual gas-
fired air heater equipped with hermetically sealed
combustion chamber and premix-burner.
The system is category II2H3P as per EN1020 and can
be supplied by natural gas (G20) and L.P.G. (G31).
It has been designed for indoor installation, directly
in the served room.
The combustion circuit is sealed from the room’s
air as prescribed by EN1020 and EN1196 for type
C: combustion air inlet and exhaust outlet ensure
the combustion air intake and the exhaust gas
expulsion.
The air heater is controlled by a micro processor
integrated in the programmable timer, which includes
the room temperature thermostat.
Upon the heating request, the control starts the premix
blower, which runs for 40 s and afterwards the burner
starts.
A flame sensor checks the burner properly started; if
any flame isn’t detected the unit will be blocked.
The exhaust gas flows throughout the inner side of
the exchanger, while the air flows over the exchanger
rising its temperature and thus warming the room.
The air flow direction can be adjusted by means of
flaps mounted onto the air outlet grate.
The air blower runs only if the exchanger’s temperature
is higher than a fixed limit (e. g. 40 °C), in order to avoid
of blowing cold air. In case of overheating of the heat
exchanger, likely due to a failure, a temperature sensor
detects the exchanger’s temperature and cut-off the
gas valve while the premix-blower and the air blower
run at maximum rpm. If the temperature keep rising,
the safety thermostat would cause the complete shut
off of the unit.
In this case the unit can be reset by the control
panel.
WARNING!
The unit reset after the safety Thermostat activation
shall be performed only by qualified operator, who
first shall identify the mode and cause of failure.
The premix-blower is placed in front of the burner and
ensure the proper air-gas ratio at any condition.
If the air intake ductor the exhaust flue either is not clean
or any obstacle would hinder the air/exhaust flow, the
electronic control is able to adjust the premix-blower
rpm and therefore the power output.
An exhaust thermostat check the proper function within
certain limit; if the exhaust temperature exceeds the
limit, the unit would be stopped.
In winter mode the unit can run in automatic or Manual
mode either (see HEATING section).
In summer mode the unit can run the air blower either in
automatic or manual mode, in order to have a pleasant
air circulation inside the room.
3.2 CONSTRUCTION FEATURES
The air heater MEC MIX COND is delivered equipped
with the following:
-
high head premix-blower,
with rpm modulation
-
combustion chamber
, made of stainless steel
-
heat exchanger
, made of stainless steel, high
heat-exchanging performance
-
covering panels
made of epoxy coated steel
- axial and centrifugal air blowers running high
flow rate and at variable rpm Further equipments
on safety:
- control board with microprocessor and noise filter,
controls the burner starting, the safety devices,
the flame modulation, the air blower rpm, the
premix blower rpm and thus the heat exchanger
temperature by means of sensor
- power supply 230 V - 50 Hz
- safety time 5 s
- chamber evacuating time 40 s
- model BRAHMA TC3 40 with ignition
Transformer model BRAHMA AR1
-
limit thermostat
90 °C, to protect the heat
exchanger against over heating
-
exhaust thermostat
, which activation will stop
the unit in case of obstruction to the air/gas or
exhaust flow; it would also activate in case of
obstruction of the internal condensate drain
- gas solenoid valve, is deactivated any time a
safety device activates and stops the gas flow
- power supply 230 V - 50 Hz
- operating temperature range 0 / 60 °C
- model SIT 848 SIGMA
