Technical data

20
8.2 DRAINING THE BOILER - Refer to Figs. 2 or 11
Isolate the electricity supply and close the boiler gas service cock (see Fig. 11). Allow the boiler to cool.
1. Heating circuit
Close the central heating flow and return valves (see Fig. 11).
Connect a suitable pipe to the drain point (see Fig. 2) and route it to a suitable container. Open the drain point.
Note: Some water will remain in the components and care must be taken when removing them.
8.3 IGNITION ELECTRODE LEAD - Refer to Fig. 21
1. Gain access to the combustion chamber as in section 8.1.
2. Disconnect the lead from the electrode.
3. Disconnect the lead from the PCB, noting its position (see Fig. 21).
4. Fit the new lead ensuring it passes through the locations in the control panel and grommets in the base of the combustion chamber.
5. Re-assemble in reverse order.
8.4 ELECTRODES - Fig. 18
Gain access to the combustion chamber 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 electrodes. Remove the grommet in the bottom of the chamber, disconnect the flame
sensing electrode in-line connector and withdraw the lead.
3. Withdraw the main burner out of the boiler. Take care not to damage the side insulation panels.
4. Flame sensing electrode
Remove the screw securing the electrode and withdraw the electrode.
Fit the new electrode, ensuring it is positioned correctly (see Fig. 18).
5. Ignition electrodes
Remove the screw securing the electrode and withdraw the electrode.
Fit the new electrode, ensuring both are positioned correctly and the spark gap is correct (see Fig. 18).
Re-assemble
1. Replace the burner, ensuring it is located correctly.
2. Replace the combustion chamber front cover, ensuring it is correctly located, especially on the sides.
3. Complete re-assembly as described in Routine Servicing, section 7.4 paragraphs 4 to 9.
8.5 MAIN BURNER
1. Remove the burner 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 as described in Routine Servicing, section 7.2.
2. Unscrew the damaged injector and screw in a replacement.
3. Re-assemble as described in Routine Servicing, section 7.4.
8.7 FAN - Fig. 19
1. Gain access to the combustion chamber as in section 8.1.
2. Disconnect the fan wiring.
3. Remove the three screws securing the fan to the flue hood. Fit the new fan and re-assemble in reverse order.
Note: Connect the fan wiring, blue to terminal N, brown to terminal L and green/yellow to terminal .
4. Re-assemble and test the boiler as described in Routine Servicing, section 7.4 paragraphs 5 to 9.
8.8 AIR PRESSURE SWITCH - Fig. 19
1. Gain access to the combustion chamber as in section 8.1.
2. Disconnect the pressure sensing tube.
3. Remove the fixing screw and disconnect the wiring.
4. Connect the wiring to the new switch. The polarity of the wires is not important.
5. Secure the new switch in position and connect the pressure sensing tube to the connection nearest the front.
6. Re-assemble in reverse order.
Alpha SY9-24 - Component Replacement