Component Replacement - Alpha CD25C Installation And Servicing Instructions

8

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, 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.
Always carry out electrical system checks i.e. Earth Continuity, Resistance to Earth, Short Circuit and Polarity with a suitable
meter after servicing.
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 8.15 does not require draining of the boiler.
8.1 GENERAL ACCESS - Fig. 26
Ensure the electrical supply is isolated and the gas supply is off.
1. If access is required behind the control panel - Lower the control cover flap and remove the two control panel fixing screws
(one each side) and lower the panel.
2. To gain access behind the casing - When the control panel is lowered, it exposes four fixing screws that secure the front cover.
Remove these screws and lift the front cover off its locating pins at the top of the boiler.
3. To gain access to the control panel components/PCB - Remove the four screws securing the rear cover and carefully
raise the cover. When replacing the cover, ensure no wires are trapped and all wiring is secured. Secure with four screws
- do not overtighten.
8.2 DRAINING THE BOILER - Refer to Figs. 2, 13
Isolate the electricity supply and close the boiler gas service cock (see Fig. 13). Allow the boiler to cool.
1. Heating circuit
Close the central heating flow and return valves (see Fig. 13).
Connect a suitable pipe to the drain point (see Fig.2) and route it to a suitable container. Open the drain point.
2. Hot water circuit
Close the mains water inlet valve (see Fig. 13).
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 - See Fig. 27
Gain access behind the room sealed chamber panel as in Section 8.1.
1. Ignition electrode and lead
Disconnect the lead from the ignition generator, noting its position.
Remove the two screws securing the electrode to the front of the combustion chamber and carefully withdraw the electrode.
2. Flame sensing electrode and lead
Disconnect the flame sensing electrode in-line connector.
Remove the two screws securing the electrode to the front of the combustion chamber and carefully withdraw the electrode.
3. Ignition electrode
Remove the two screws securing the electrode to the front of the combustion chamber and carefully withdraw the electrode.
Re-assemble in reverse order
8.4 MAIN BURNER - Fig. 27
1. Remove the burner assembly as described in Routine Servicing, Section 7.2.
2. Remove the four screws securing the burner to the combustion chamber front assembly.
3. Re-assemble with a new burner as described in Routine Servicing, Section 7.4.
8.5 BURNER INJECTOR - Fig. 26
1. Gain access to the room sealed chamber as described in Section 8.1.
2. Undo the gas inlet union to the combustion chamber front to gain access.
3. Unscrew the damaged injector and screw in a replacement.
4. Re-assemble in reverse order.
Alpha CD25C/28C/35C - Component Replacement 25