28
8.11 GAS VALVE - Fig. 26
1.
Gain access behind the casing as in Section 8.1.
2.
Disconnect the coil wires and pressure tube from the gas valve.
3.
Loosen the one screw (see Fig. 26) securing the electrical plug
and disconnect the plug.
4.
Disconnect the burner manifold union and the gas inlet pipe union
from the manifold.
5.
Remove the two manifold screws from beneath the boiler.
6.
Carefully push the valve towards the rear of the boiler (take care
not to damage the manifold sealing washer) and lift out the valve
assembly.
7.
Fit the new assembly and re-assemble in reverse order.
8.
Light the boiler and test for gas soundness. (Refer to
Commissioning, Section 5.4).
9.
Complete re-assembly as described in Routine Servicing, Section
7.4 paragraphs 5 to 9.
8.12 VIEWING WINDOW - Fig. 24
1.
Gain access behind the casing as in Section 8.1.
2.
Remove the rubber window frame and remove the damaged glass.
3.
Re-assemble in reverse order with a new glass. Ensure the rubber frame is located correctly in the front panel.
8.13 INTERNAL FUSE - Refer to Fig. 20
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.
8.14 PCB - Fig. 27
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 HE CB25/33, SY25 - Component Replacement
Fig. 26
Fig. 27
Fig. 28 - HE CB25/33 only
8.15 DHW FLOW SWITCH (HE CB25/33 only) - Fig. 28
1.
Gain access behind the casing as described in Section 8.1.
2.
Remove the switch from the diverter valve by pulling or prising it upwards from the valve body. Disconnect the inline wiring
connector. Re-assemble in reverse order with a new switch. Ensure that the switch is located correctly.
Summary of Contents for Alpha HE CB25
Page 34: ...34 Alpha HE CB25 33 SY25 Wiring Diagrams 9 2 HE SY25 ILLUSTRATED WIRING DIAGRAM...
Page 35: ...35 9 3 HE CB25 33 FUNCTIONAL FLOW WIRING DIAGRAM Alpha HE CB25 33 SY25 Wiring Diagrams...
Page 36: ...36 9 4 HE SY25 FUNCTIONAL FLOW WIRING DIAGRAM Alpha HE CB25 33 SY25 Wiring Diagrams...
Page 39: ...39 Alpha HE CB25 33 SY25 Fault Finding 10 4 FAULT FINDING SOLUTIONS A to F...
Page 40: ...40 Alpha HE CB25 33 SY25 Fault Finding 10 5 FAULT FINDING SOLUTION SECTIONS G to J...
Page 41: ...41 Alpha HE CB25 33 SY25 Fault Finding 10 6 FAULT FINDING SOLUTION SECTIONS K to L...
