Technical data

23
8.12 INTERNAL FUSE - Refer to Fig. 14
The fuse is located in the boiler terminal block.
1. Gain access as described in Installation, section 4.8.
2. Lift out the fuse holder and remove the fuse. Fit a fast blow 2 A fuse as a replacement, ensuring that the holder snaps into position.
3. Re-assemble in reverse order, ensuring the terminal block is located correctly on the plastic pins.
8.13 PCB - Fig. 22
1. Gain access behind the control panel as described in section 8.1.
2. Disconnect all the wiring connectors from the PCB.
3. Remove the five fixing screws and carefully withdraw the board from the switch spindles.
4. Re-assemble in reverse order. Refer to the wiring diagram in section 9.1 for connections.
Alpha C23/27 - Component Replacement
Fig. 22
Fig. 23
8.14 DHW FLOW SWITCH - Fig. 23
1. Gain access behind the casing and drain the DHW circuit.as described in section 8.1.
2. Disconnect the wiring from the flow switch.
3. Disconnect the two unions and remove the switch.
4. Using a new washer reassemble in reverse order.
8.15 CLOCK (if fitted) - Refer to Fig. 15
1. Gain access behind the control panel as described in section 8.1.
2. Remove the two screws securing the clock cover at the rear of the control panel.
3. Disconnect the wiring from the clock.
4. Remove the clock retaining screws and withdraw the clock from the control panel.
5. Fit the new clock, and connect the wires as follows:-
Blue to terminal 1, Brown to terminal 2 and Red wires to terminals 3 and 4, (or as per the instructions supplied with the clock).
6. Re-assemble in reverse order. Refer to the User's instructions and the boiler's control cover to set the clock.
8.16 PRIMARY/DHW HEAT EXCHANGER
1. Gain access to the combustion chamber and drain the boiler heating and DHW circuits as described in sections 8.1 and 8.2.
2. Remove the four screws securing the combustion chamber front cover and remove the cover.
3. Remove the overheat thermostat (section 8.9) and the CH temperature sensor (section 8.19).
4. Remove the two screws securing the rear baffle plate and remove the plate.
5. Disconnect the two unions from the heat exchanger flow and return pipes.
6. Lift up the heat exchanger off the pipes and remove it by carefully withdrawing it out of the boiler.
7. Remove the pipes from the heat exchanger by releasing the four union connections.
8. Fit the pipes to the new heat exchanger, ensuring new washers are used. Ensure the heat exchanger is correctly located.
9. Re-assemble in reverse order.
10. Refill and pressurise the system. (Refer to Commissioning, section 5.1).
DHW flow switch