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27. THE CENTRAL HEATING CIRCULATING PUMP
Fig. 29.
(a) Turn off the isolating valves mounted on the inlet and outlet
pump.
(b) Remove the left hand side panel support strap.
(c) Undo the two union nuts, remove the pump and discard the
sealing washers. If the connections are found to be excessively
tight then the left hand cabinet side panel may be removed
to give increased access.
(d) Remove the two screws holding the electrical cover on the
pump and disconnect the electrical leads and note the wire
positions.
(e) Fit the replacement circulating pump using new sealing
washers.
NOTE. The direction flow indicator on the circulating pump
should point towards the rear of the boiler. The replacement
pump should be set at maximum speed if fitted with a speed
adjuster.
(f)
Open the isolating valves.
(g) Reassemble the appliance in the reverse order.
28. THE FLOW REGULATORS
Fig. 29.
Fig. 29.
Flow
regulators
Central
heating
pump
Cold water
inlet
Domestic hot
water flow
NOTE. The appliance is fitted with two plastic flow regulators
and wire mesh filters in the cold water supply. They are located
in the cold inlet manifold to the water-to-water heat
exchangers_
For better access to the right hand flow regulator housing nut
the central heating circulating pump may be removed. Follow
instructions 27a, band censuring the sealing washers are not
mislaid. Place the pump on top of the heat bank taking care not
to strain the wire.
(a) Turn off the mains cold water supply.
A
residue of the water will
remain in the pipe. Open a cold water tap to drain the
pipework.
(b) Unscrew the flow regulator housing union nuts and ease the
cold water manifold aside. It may be necessary to unclip the
supply pipe.
(c) Remove the wire mesh filter from the upper half of the housing
and take care not to loose the fibre washer. Wash the filter in
clean water.
(d) Remove the plastic flow regulator from the lower half of each
housing. It may be necessary to prise the regulator from the
housing.
(e) Fit a new flow regulator (small diameter section first) and
reassemble in the reverse order. Replace the fibre sealing
washers if necessary. Sealing compound should not be used.
Central heating
return
Central heating
flow
Combined feed
and vent
24
Domestic
hot water
high limit
thermostat
Pressure
relief pipe
-----
Safety
valve
Automatic
air vent
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