Fan, Venturi Device And Air Pressure Switch; Function; Checks; Removal Of The Fan - QHT RIVA FP Service Instructions Manual

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Third Part
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Fan, Venturi Device and Air Pressure
Switch

1) Function

2) Checks

3) Removal of the Fan

4) Inspection and Removal of the Venturi
Device
5) Removal of the Air Pressure Switch
1 Function
The function of the Fan A (Figure 1) is to force
the products of combustion to the outside air via
the flue system.
The Fan is supplied by the Fan and air pressure
device at the beginning of the ignition cycle.
Its correct functioning is controlled by means of a
system incorporating a built in venturi device B
and an Air pressure switch C (Figure 1).
2 Checks
A Check of the fan
Warning: Isolate the boiler from the mains
electricity supply before removing
any covering or component.
RIVA FP SERVICE MANUAL - REV A
(edition-0106)
B
C
A
Figure 1

Fan, Venturi Device and Air Pressure Switch

1) Remove all the case panels and the sealed
chamber lid.
2) Disconnect the connectors D (Figure 2) and
measure the electrical resistance of the motor
that has to be about: 7.2 Ω.
F
B Check of the Air pressure switch operation
Warning: Isolate the boiler from the mains
electricity supply before removing
any covering or component.
1) Remove all the case panels and the sealed
chamber lid.
2) Disconnect the wires and check the electrical
resistance between the connections of the Air
pressure switch.
Refer to the Figure 3 in accordance with the type
of air pressure switch used.
"-" connection
N.C.
Between COM and N.O. the contact must be
open.
Between COM and N.C.the contact must be
closed (electrical resistance zero).
3) Connect the black (COM) and the brown wire
(N.C.).
4) Run the boiler (the Fan must run) and check
the electric resistance between COM and
N.O.. Between COM and N.O. the contact
must be closed (electrical resistance zero).
E
Figure 2
COM
"+" connection
Figure 3
D
N.O.
13-1