Technical data
24
8.9 FAN - Fig. 21
1. Gain access as in section 8.1.
2. Remove the five screws securing the combustion
chamber front cover and remove the cover.
3. Disconnect the air pressure tubes from the fan outlet.
4. Loosen the fan to flue adaptor clamp screws and
raise the clamp as far as possible.
5. Remove the two screws securing the flue hood to the
back panel and withdraw the assembly sufficiently to
disconnect the fan wiring.
6. Remove the four screws securing the fan to the flue
hood. Transfer the fan outlet casing to the new fan
and re-assemble in reverse order.
Alpha 240XE - Connect the fan wiring, blue to terminal
1 and brown to terminal 2.
Alpha 240XP - Connect the fan wiring, blue to terminal
'MIN', brown to terminal 'MAX' and black to terminal 'COM'.
Ensure the pressure tubes are connected correctly (see
Fig. 21). ( and + marked on the fan outlet), and that
the bottom of the combustion chamber cover is located
in the burner.
7. Re-assemble and test the boiler as described in Routine
Servicing, section 7.4 paragraphs 5 to 9.
8.10 AIR PRESSURE SWITCH - Fig. 22
1. Gain access as in section 8.1, remove the five screws securing the combustion chamber front cover and remove the cover.
2. Disconnect the pressure sensing tubes.
3. Remove the two fixing screws and disconnect the wiring.
4. Connect the wiring to the new switch, black to C, brown to NC, blue to NO and reconnect the pressure tubes (see Fig. 22).
5. Secure the new switch in position.
6. Re-assemble in reverse order.
8.11 OVERHEAT THERMOSTAT - Fig. 23
1. Gain access as in section 8.1.
2. Alpha 240XP - Disconnect the thermocouple from the gas valve and withdraw the overheat thermostat lead. Unscrew the
other overheat thermostat lead from the back of the gas valve - accessible from the boiler base.
Alpha 240XE - Disconnect the wiring from the overheat thermostat.
3. Remove the two fixing screws and remove the overheat thermostat from the CH flow pipe.
4. Fit the new overheat thermostat and re-assemble in reverse order.
Fig. 21
Alpha 240XP and 240XE - Component Replacement
Flue spigot
clamp
Flue
hood
screws
Pressure
sensing tubes
Air pressure switch
connections
Combustion
chamber
front screws
Fig. 22 Fig. 23
NO (Blue wire)
(Brown wire) NC
(Black wire) C
Pressure sensing tubes
Overheat
thermostat
Thermostat lead
connections
(Alpha 240XP)