Technical data

23
Alpha 500E - Component Replacement
8.5 MAIN BURNER
1. Remove the burner assembly as described
in Routine Servicing, section 7.2.
2. Re-assemble with a new burner as
described in Routine Servicing, section 7.4.
8.6 BURNER INJECTORS
1. Remove the burner assembly as described
in Routine Servicing, section 7.2.
2. Remove the two screws securing the burner
to the injector manifold and remove the
burner.
3. Unscrew the damaged injector and screw in
a replacement.
4. Re-assemble as described in Routine Servicing, section 7.4.
8.7 FAN - Fig. 23
1. Gain access as in section 8.1.
2. Remove the four 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 fan to the flue hood 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.
Note: Connect the fan wiring, blue to terminal 1 and brown
to terminal 2. Ensure the pressure tubes are connected
correctly, (red tube to +, clear tube to marked on the fan
outlet as shown in Fig. 23), and that the bottom of the
combustion chamber cover is located correctly.
7. Re-assemble and test the boiler as described in Routine
Servicing, section 7.4 paragraphs 5 to 9.
8.8 AIR PRESSURE SWITCH - Fig. 24
1. Gain access as in section 8.1.
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, (red tube to +, clear
tube to , see Fig. 24).
5. Secure the new switch in position.
6. Re-assemble in reverse order.
8.9 OVERHEAT THERMOSTAT - Fig. 25
1. Gain access as in section 8.1.
2. Disconnect the wiring from the thermostat.
3. Remove the two fixing screws and remove the thermostat from the primary
flow pipe.
4. Fit the new thermostat and re-assemble in reverse order.
Primary
flow pipe
Fig. 25
Overheat
thermostat
No (Blue wire)
Pressure sensing tubes
(Black wire) C
(Brown wire) Nc
Fig. 24
Fig. 23
Fan/flue hood
screws
Flue hood
screws
Flue adaptor
clamp
-
+
Pressure
sensing
tubes
8 to 10 mm
Flame sensing
electrode
11 to 12 mm
Securing
screws
2.0 to 3.5 mm
Ignition
electrodes
Fig. 22Fig. 21
Air
pressure
switch