30
8.20 TEMPERATURE SENSORS - Refer to Fig. 28 and 34
Note that both sensors are the same.
1.
Gain access as described in section 8.1 (behind the casing for the DHW sensor or behind the room sealed chamber panel
for the primary temperature sensor) and drain (heating circuit for primary sensor or hot water circuit for DHW sensor) as
described in section 8.2.
2.
Primary Sensor - The primary sensor is positioned on the right hand side of the heat exchanger, see Fig. 28. Disconnect
the wiring and unscrew the sensor. Re-assemble in reverse order with a new sensor and sealing washer.
2a. DHW Sensor (CD24C and CD32C only) - Close the mains cold water inlet valve and open the lowest hot water tap to
drain the DHW system. Disconnect the wiring and unscrew the sensor from the hot water outlet pipe from the DHW plate
heatexchanger, see Fig 34. Re-assemble in reverse order with a new sensor, replacing the sealing washer if necessary.
8.21 AUTOMATIC AIR VENT - Fig. 33
1.
Gain access behind the casing and drain the boiler heating circuit as described in sections 8.1 and 8.2.
2.
Unscrew the automatic air vent from the pump outlet. Fit a new one using a new 'O' ring.
3.
Refill and pressurise the system. (Refer to Commissioning, section 5.1).
8.22 PUMP - Refer to Fig. 33
Gain access behind the casing and drain the boiler heating circuit as described in sections 8.1 and 8.2.
Pump head
1.
Remove the four socket head screws securing the pump head to the body. Withdraw the head, remove the wiring cover
and disconnect the wiring.
2.
Connect the wiring to the new head as follows:-
Brown to L, Blue to N, Green/yellow to
.
Ensure the pump is set to maximum (3) and re-assemble in reverse order.
3.
Refill and pressurise the system. (Refer to Commissioning, section 5.1).
Complete pump
1.
Remove the pump head as described above.
2.
Unscrew the automatic air vent from the pump outlet.
3.
Disconnect the pump unions and withdraw the pump body.
4.
Connect the wiring as described above, ensure that pump is set to maximum and re-assemble using new sealing washers.
5.
Refill and pressurise the system. (Refer to Commissioning, section 5.1).
8.23 PRIMARY PRESSURE SWITCH - Fig. 33
1.
Gain access behind the casing and drain the boiler heating circuit as described in sections 8.1 and 8.2.
2.
Disconnect the wiring from the pressure switch.
3.
Unscrew the switch from the primary flow pipe.
4.
Using the new washer supplied, re-assemble in reverse order.
When connecting the wiring to the new switch the polarity of the wires is not important.
8.24 PRESSURE RELIEF VALVE - Fig. 33
1.
Gain access behind the casing and drain the boiler heating circuit as described in sections 8.1 and 8.2.
2.
Remove the four screws securing the bottom tray and remove the tray. Disconnect the pressure relief valve outlet fitting.
3.
Release the screw retaining the pressure relief valve and pull out the valve.
4.
Re-assemble in reverse order.
5.
Refill and pressurise the system. (Refer to Commissioning, section 5.1).
Alpha CD24/32 - Component Replacement
Summary of Contents for Alpha CD24
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