Technical data

22
Alpha 500E - Component Replacement
It is the law that any service work must be carried out by a competent person, i.e. CORGI registered personnel.
Warning: Before replacing any boiler components, set the selector switch to 0, isolate the electrical supply and close the boiler
gas service cock. Allow the boiler to cool.
Always test for gas soundness after replacing any gas carrying components or disturbing any gas connections.
Check the operation of the boiler. (Refer to Boiler Operation, section 6). Ensure that all the controls are returned to their original settings.
The replacement of components in sections 8.3 to 8.21 does not require draining of the boiler.
The replacement of components incorporated within the unvented kit are detailed in sections 8.35 to 8.38.
8.1 GENERAL ACCESS - Fig. 20
Ensure the electrical supply is isolated and the gas supply is off.
Remove the two screws securing the top of the front casing. Lift the cover up slightly and remove.
1. If access is required behind the control panel - Remove the two fixing screws (one each side) securing the control
panel and hinge it forward.
2. To gain access to the combustion chamber - Remove the four screws securing the room sealed chamber panel and
remove the panel, taking care not to damage the seal. When replacing the panel, ensure the seal is intact and in position.
3. To gain access to the control panel components - Remove the five screws securing the rear cover and carefully raise
the cover from the front. When replacing the cover, ensure no wires are trapped and all wiring grommets are in position.
Secure with five screws - do not overtighten.
4. If access is required from underneath the boiler - Remove the two screws securing the bottom casing panel and, by
pulling the panel forward, lift it from its location.
8.2 DRAINING THE BOILER - Refer to Fig. 13
Set the selector switch to 0, isolate the electrical supply and close the boiler gas service cock (see Fig. 13). Allow the boiler to cool.
Remove the two screws securing the top of the front casing. Lift the cover up slightly and remove. Remove the two fixing
screws (one each side) securing the control panel and hinge it forward.
1. Heating circuit (refer to Fig. 13)
Close the central heating flow and return valves and drain the heating circuit via the drain point.
2. Hot water circuit (refer to Fig. 13)
Close the mains water supply valve and drain the hot water storage cylinder via the drain tap at point I, Fig. 13 - Access to
the drain tap is gained by removing the bottom casing panel (refer to section 8.1 paragraph 4). Open any hot tap below
the level of the boiler to allow as much draining as possible.
Note: Some water will remain in the components and care must be taken when removing them.
8.3 ELECTRODES - Figs. 21, 22
Gain access as in section 8.1.
1. Remove the four screws securing the combustion chamber front cover and remove the cover.
2. Disconnect the leads from the ignition electrodes.
3. Disconnect the main burner's union and withdraw the burner out of the boiler. During removal of the burner, disconnect the
flame sensing electrode lead and take care not to damage the side insulation panels.
4. Flame sensing electrode - Fig. 21
Remove the screw securing the electrode and withdraw the electrode.
Fit the new electrode, ensuring it is positioned correctly (see Fig. 21).
5. Ignition electrodes - Fig. 22
Remove the screws securing the electrodes and withdraw the electrodes.
Fit the new electrodes, ensuring they are positioned correctly and the spark gap is correct (see Fig. 22).
Re-assemble
1. Replace the burner, ensuring it is located correctly onto the side panels and that the leads to the flame sensing and
ignition electrodes are connected. Connect the main burner's union nut and tighten.
2. Replace the combustion chamber front cover, ensuring the bottom is correctly located in the burner.
3. Complete re-assembly as described in Routine Servicing, section 7.4 paragraphs 3 to 9.
8.4 IGNITION ELECTRODE LEAD - Refer to Fig. 27
1. Gain access as in section 8.1.
2. Disconnect the lead from the electrodes.
3. Disconnect the lead from the ignition PCB, noting its position (see Fig. 27).
4. Fit the new lead ensuring it passes through the grommets in the control panel cover and base of the combustion chamber.
5. Re-assemble in reverse order.
8 COMPONENT REPLACEMENT