13. Domestic Hot Water Sensor.
Check that the electricity supply to the appliance is turned off. Hinge the facia assembly in the servicing position as described in Section 14.3(c and d).
Carefully pull off the two leads from the sensor. Undo and remove the clamping screw.
Pull off the sensor and spring retaining clip from the pipe.
Fit the replacement sensor in the reverse order ensuring a layer of heat sink compound is between the faces. Refit the leads.
14. Circulating Pump. See Figs. 32 and 34.
Check that the electricity supply to the appliance is turned off. Drain the central heating circuit as described in Section 15.3(a). Hinge the facia assembly in the servicing position as described in Section 14.3(c).
Undo the two union nuts and the pipe to the expansion vessel, remove the pump from the
Disconnect the electrical wires taking note of their positions.
Fit the replacement pump in the reverse order using new sealing washers.
(Alternatively replace the pump head only by removing the four Allen screws on the pump, remove the head and support whilst removing the electrical connections. Refit the new head).
Open the valves and fill and
Note: The direction of flow should be upwards. The speed should always be set to maximum.
15. Expansion Vessel.
Drain the central heating circuit as described in Section 15.3(a). Isolate the gas supply at the mains.
Then either fit a separate expansion vessel on the central heating return to the appliance or replace the existing vessel as described below.
Drain the domestic circuit as described in Section 15.3(b). Disconnect the flue system at the boiler.
Disconnect the appliance pipework at the appliance entry points ensuring precautions are taken to cope with any water remaining in the appliance.
Remove the appliance from the wall.
Disconnect the expansion vessel from the appliance by undoing the fitting nut at itÕs base.
Fit the replacement vessel in the reverse order.
Open the valves and fill and
Fig. 35. Pressure relief valve.
Pressure relief valve.
(Turn knob
16. Pressure Relief Valve. See Fig. 35.
Drain the central heating circuit as described in Section 15.3(a). Hinge down the facia assembly as described in Section 14.3(c) Remove the Bottom panel as described in Section 14.3(d)
Undo the discharge pipe connection and remove the valve retaining clip. Remove the valve taking care not to distort the pipework.
Fit the replacement valve in reverse order. Reconnect the discharge pipe.
Open the valves and fill and
17. Water Flow Switch. See Fig. 36.
Check that the electricity supply to the appliance is turned off. Drain the domestic hot water circuit as described in Section 15.3(b).
Remove the two upper screws and hinge down the facia panel as described in Section 14.3(c).
Undo the two union nuts securing the ÒTÓ piece and remove the housing from the pipework.
Disconnect the electrical connection.
Fit the replacement water flow switch in the reverse order ensuring new fibre washers are fitted to the new switch body.
Fig. 36. Water Flow Switch. (Side View)
Flow Restrictor
Water Flow Switch
ÒTÓ Piece
18. Domestic Hot Water Flow Restrictor. See Fig. 36.
Remove the water flow switch as described in Section
The plastic flow restrictor is located within the ÒTÓ piece on the water flow switch.
Fit the replacement flow restrictor and reassemble in the reverse order ensuring the fibre washers are in place.
19. Pressure Gauge.
Check that the electricity supply to the appliance is turned off. Drain the central heating circuit as described in Section 15.3(a). Remove the two upper screws and hinge down the facia panel as described in Section 14.3(c).
Prize back the retaining clips securing the gauge to the facia panel remove wire clip and unplug the gauge from the pump inlet pipe.
Fit the replacement gauge in the reverse order ensuring the ÒOÓ ring is in place.
Open the valves and fill and
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