Technical data

33
Alpha 240XP and 240XE - Component Replacement
8.39 DHW FLOW VALVE - Fig. 39
1. Drain the boiler hot water circuit as described in
section 8.2.
2. Remove the flow switch assembly from the front
of the diverter valve.
3. Disconnect the two flow sensing pipes from the
flow valve.
4. Unscrew (not necessary to remove) the two
screws securing the DHW flow valve to the
diverter valve (one screw accessible from
beneath the boiler) and withdraw the valve.
5. When re-assembling, push the new valve into
position, holding it in, while tightening the fixing
screws.
6. Re-assemble in reverse order.
8.40 PRIMARY FLOW VALVE DIAPHRAGM - Fig. 40
1. Drain the boiler heating circuit as described in
section 8.2.
2. Remove the flow switch assembly from the top
of the diverter valve.
3. Disconnect the small pipe from the back of the
flow valve.
4. Remove the four screws securing the flow valve
and carefully remove it from the diverter valve.
5. Replace the diaphragm and re-assemble in
reverse order.
6. Refill and pressurise the system. (Refer to
Commissioning, section 5.1).
8.41 EXPANSION VESSEL
1. Drain the boiler heating circuit as described in
section 8.2.
2. Disconnect the pipe from the diverter valve and
expansion vessel.
3. Remove the nut and washer securing the
expansion vessel to the boiler and lift the vessel
out of the boiler.
4. When replacing the vessel, ensure that the
connection is towards the front of the boiler and
re-assemble in reverse order using new seals as necessary.
5. Refill and pressurise the system. (Refer to Commissioning, section 5.1).
Note: If there is less than 350 mm clearance above the boiler or rear exit flue, it is not possible to replace the vessel, in which
case an additional vessel should be fitted external to the boiler in the central heating return pipe, as close to the boiler as
possible (see Fig. 6).
8.42 DHW EXPANSION DEVICE (if fitted) - Refer to Fig. 35
1. Drain the boiler hot water circuit as described in section 8.2.
2. Unscrew the device from its fitting.
3. Fit the replacement using a new seal.
4. Re-assemble in reverse order.
Fig. 39
Fig. 40
DHW flow
sensing
pipes
DHW flow valve
DHW flow
microswitch assy.
DHW flow valve
securing screws
Diaphragm
Small by-pass
pipe
Primary flow
microswitch assy.