12. Central Heating Sensor.
See figs. 32 and 33.
Check that the electricity supply to the appliance is turned off.
Remove the inner casing cover as described in Section 13.3 (b).
Carefully pull off the two leads from the sensor.
Pull off the sensor and spring retaining clip from the pipe.
Discard the sensor retain the clip.
Fit the replacement sensor in reverse order with a layer of heat
sink compound between the faces.
Refit the leads. Polarity is not important.
Reassemble the appliance in the reverse order.
13. Domestic Hot Water Sensor.
See figs. 37 and 39.
Check that the electricity supply to the appliance is turned off.
Hinge the facia panel down into the Servicing Position as
described in Section 13.3 (c).
Carefully pull off the two leads from the sensor.
Remove the clamping screw, pull off the sensor and spring
retaining clip from the pipe. Discard the sensor, retain the screw
and clip.
Fit the replacement sensor in the reverse order ensuring a layer
of heat sink compound is between the faces. Refit the leads.
Polarity is not important.
Reassemble the appliance in the reverse order.
14. Circulating Pump.
See figs. 37 and 38.
Check that the electricity supply to the appliance is turned off.
Drain the central heating circuit as described in Section 14.2 (a).
Hinge the facia panel down into the Servicing Position as
described in Section 13.3 (c).
Unscrew the two pump union nuts and the pipe to the
expansion vessel. Ease the pump from the pipe-work. Support
the pump and remove the electrical cover.
Disconnect the electrical wires taking note of their positions.
Remove the pump from the appliance.
Unscrew the expansion vessel brass connection from the pump.
Discard the pump retain the brass connection.
Fit the brass connection to the replacement pump using sealing
compound on the threads.
Fit the replacement pump in the reverse order using new sealing
washers.
Reassemble the appliance in the reverse order.
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. Discard the head. Refit the
new head.
Open the valves and fill and re-pressurise the system as
described in Section 11.1.
Note: The direction of flow should be downwards. The speed
should always be set to maximum.
28
Fig. 37. Appliance Components (lower assembly)
Domestic hot water
sensor (not shown)
located behind water to
water heat exchanger
Circulating pump
Flow pipe from pump and
union connection
Expansion vessel
Air pressure switch
Gas valve
Water to water
heat exchanger
Pressure relief
valve
Drain tap
(C.H. Return)
Pressure Gauge
Facia and controls shown
in the service position
Plastic water
cover
Filling loop
Water diverting valve
and micro switch
assembly
Drain tap C.H. flow
Summary of Contents for 26CDi Xtra
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