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4.4. SMOKE
DRAFTING
PASS-THROUGH CHAMBER AND FAN
The gazes resulting from the combustion process, after being released their heat charge to the water, are
collected in the smoke pass-through chamber located in the rear part of the boiler. In the smoke chamber has
place the drafting fan with horizontal axle arrangement, realized with an electric motor and the impeller. The
fan is easy to be maintained being fixed with wing nuts.
4.5. AIR DISTRIBUTION ASSEMBLY
In the front part of the boiler, in the middle between the upper and the bottom door, is located the combustion
air suction port. The immission duct has an internal gravitational closing door which closes the air passage
when the drafting fan stops, and another temperature commanded external closing.
The air entering in the air chamber is then divided in primary and secondary air stream. The main air stream
enters the wood collecting chamber and creates the combustible mixture which is fired after passing through
the cast iron grate. The secondary air stream flows through some internal ducts realized in the refractory
cement layer thickness encountering the wood gazes in the burner central slot, where starts the flame,
optimizing the combustion process.
4.6. HOT SANITARY WATER HEAT EXCHANGER
The ASPIRO boiler may be equipped with an internal real time heat exchanger for hot sanitary water
production purposes (SA models only). The heat exchanger is realized with a copper pipe coil plunged in the
heating circuit water gap, around the boiler main body, with the hidraulic connections in the rear part of the
boiler.
4.7. EMERGENCY
HEAT
EXCHANGER
The boiler is equipped with a security heat exchanger. Its function is to let the boiler cooling down in the
evenience of reaching excessive temperature by the mean of a heat relief valve connected to the security
exchanger (refer to paragraph 5.5). This is realized by a steel pipe coil with its hidraulic connections in the
rear part of the boiler (connections “A5”). The temperature sensor of the heat relief valve is to be positioned
on the A6 connection.
4.8. PROBES
RECEPTACLES
In the rear part of the boiler are two holes (A6) both with a ½” pipe coupling having the following function:
to fit the copper receptacle for installing the thermostatic sensors used by the electronic control board;
to fit another copper receptacle for other temperature sensing device.
4.9. BYPASS PUMP
With the aim to reduce any condensation in the boiler it is mandatory to install a bypass pump . The bypass
pump must be connected between the delivery connection (A1) and the return connection (A2) with water
flux direction upward. Our company may deliver the whole bypass kit, complete with bypass pump, pipes and
fittings.
4.10. INSULATION
Insulation of ASPIRO boiler is obtained using a 60 mm thickness mineral fiber layer in touch with the boiler
body which is covered by the external boiler housing, realized by sheet metal panels painted with epoxy
powder paint.