Description of functioning
t e c h n i c a l
21
3.1.4- Air Circuit
Characteristics of the air circuit components:
Fan:
(Part number MCB2030)
The function of the fan is to
draw
in air from the outside and evacuate the burnt gases
produced during combustion
.The 24kW boiler fan has a power of 35W.
Part number MCB2030
Air pressure switch:
(Part number
MCB
3100
)
This component ensures that the fan is running, that there are no obstructions anywhere
in the
flue or in the flue venturi, also checks that the flue is
install
ed and working correctly
24kW boiler ->
120
/
100
Pa pressure switch
If a pressure switch is calibrated to
120
/
100
Pa, for example, this means that the pres-
sure switch contacts are activated at a differential pressure of 1
20
Pa (1
.
2
mb
) and
deactivated at
100
Pa (
1.0
m
b
).
To measure the differential pressure, fi rst measure the pressure using the
manometer
on
one of the
pressure
port
s, and then with the
manometer
on
the other. The
result will be the sum total of both.
This data is to be taken as an approximate value only, as variations of a few Pascals
occur in the measur
e
ments while the fan is running.
Flue
Venturi :
(Part number MCB2100)
This is fi tted to the
fan
outlet pipe. When the
air or flue gases
fl ow through it, a pressure difference is produced which must
be great enough to activate the differential air pressure switch
.
PLEASE NOTE THAT DURING PERIODS OF SHUT DOWN. THE
FLUE VENTURI MAY BECOME BLOCKED WITH INSECTS.
IT WILL BE NECESSARY TO REMOVE AND CLEAN THE VENTURI..
THE VENTURI WILL ONLY FUNCTION CORRECTLY WHEN FITTED
WITH THE LONGEST PART FACING UPWARDS(- TO TOP)
+
-
MCB3100
18
