Removal; Pump; Function; Checks - Biasi GARDA M90F.24S Service Manual

7

Pump

7.1

Function

The pump A in Fig. 17 has the function of making the
water in the main circuit circulate through the main heat
exchanger and therefore through the c.h. system (dur-
ing the c.h. function) or through the secondary heat ex-
changer (during the d.h.w. function).
Fig. 17
7.2

Checks

Warning: isolate the boiler from the mains
electricity supply before removing any
covering or component.
Check that the pump is not seized and that the
n
movement of the rotor is not subject to mechanical im-
pediments.
With the boiler off, remove the front panel. Remove the
air release plug of the pump and turn the rotor with a
screwdriver.
Check the electrical continuity.
n
With the boiler off, remove the front panel and discon-
nect the connector B (Fig. 18).
Measure the electrical resistance between the pump
supply connections.
Electrical resistance of the windings (at ambient tem-
perature) must be about 230 Ω
Check the absence of starting defects.
n
With the boiler off remove the front case panel.
Remove the air release plug from the pump. Start the
boiler and with a screwdriver, turn the rotor in the direc-
tion of the arrow. If there is a defect in starting, the rotor
will begin to turn normally only starting it manually.
12
A
Check that the impeller is integral with the rotor.
n
With the boiler off remove the front and right hand side
case panels, lower the control panel and empty the pri-
mary circuit.
Remove the pump head by undoing the screws which
hold it to the pump body and check that the impeller is
firmly joined to the rotor.
7.3

Removal

Warning: isolate the boiler from the mains
electricity supply before removing any
covering or component.
1 Remove the front and right hand side case panels
2 Empty the primary circuit of the boiler.
3 Extract and lower the control panel.
4 Disconnect the connector B (Fig. 18).
Unscrew the connection C and move the pipe up-
5
wards freeing it from the outlet port of the pump.
6 Remove the fork D and the capillary pipe .
Remove the locking plate E right (Fig. 18).
7
C
B
D
Fig. 18
Loosen the connection F, remove the fork G and
8
the pipe H.
Unscrew the two screws I that hold the pump on
9
the frame (Fig. 19) and remove the pump towards
the front of the boiler.
F
Fig. 19
Reassemble the pump carrying out the removal oper-
ations in the reverse order. When reassembling the
pump, check the correct location of the O---ring gasket
in the inlet port of the pump that seals the connection
between the pump and the brass group .
E
G
H
I