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FAN AND AIR BOX
10 FAN AND AIR BOX
10 .1 Function
The function of the Fan "A" (Figure 10.1) is to force the mixture of
air and gas into the burner.
The function of the Air box "B" is to mix the gas and the air in the
right proportion.
The flow rate of the air-gas mixture and consequently the input
power of the boiler is proportional to the speed of the fan that is
controlled by the electronic control p.c.b.
Figure 10 .1
A
B
10 .2 Removal of the Air box and the Fan
Warning: isolate the boiler from the mains electrici-
ty supply before removing any covering or compo-
nent .
1 Turn off the gas supply.
2 Remove all the case panels (see section "2 General access
and emptying hydraulic circuits" on page 4).
Figure 10 .2
C
D
E
F
A
B
G
H
3 Disconnect the air manifold "E" (Figure 10.2).
4 Unscrew the gas connector "F" and remove the gas pipe "G".
5 Disconnect the connector "C".
6 Disconnect the fan connector "D" by pressing the plastic
hook placed on the side of the connector.
7 Unscrew the screws "H".
8 Remove the fan "A" with the air box "B".
9 Assemble the Fan carrying out the removal operations in re-
verse sequence.
Before reassembling ensure the fan gasket (Figure 10 .2) is
correctly mounted .
Warning: Place the seal on the pipe and offer the
pipe with O'ring pre fitted into the manifold rather
than inserting the O'ring into the manifold and offer-
ing the pipe into it .
After any service operation on the components of the gas
circuit check all the connections for gas leaks .
Warning: After cleaning or replacement as detailed
above, it is deemed necessary to undertake a com-
bustion analysis as detailed in section "8 .3 Adjust-
ment" on page 22 .
