Alpha InTec2 25XE Installation And Servicing Instruction page 41

7.6 FLUE TEMPERATURE SENSOR - Fig. 6.7
Gain access as described in Section 7.1.
1. Unplug the wire from the flue sensor.
2. Using a 13 mm spanner, unscrew the sensor from the flue outlet manifold.
3. Fit the new sensor and re-assemble in reverse order. Do not overtighten.
7.7 FUSE - Fig. 7.1
The fuse is located on the PCB.
1. Gain access to the PCB as described in Section 7.8.
2. Lift out and remove the fuse. Fit a 3.15 AF fuse as a replacement.
3. Re-assemble in reverse order.
7.8 PCB - Fig. 7.1
Note: The replacement of the gas valve or PCB must be carried out
by a Gas Safe registered engineer with the use of a flue analyser.
Gain access as described in Section 7.1.
1. Unhook the ignition lead from the rear of the control panel, release the grommet and unplug the lead from the PCB.
2. Remove the three retaining screws in the PCB cover and remove cover. See Fig. 7.2.
3. Remove the PCB retaining screws.
4. Release the retaining clips, lift the PCB from the control panel and unplug the wire connections.
5. To maintain the boiler parameter setting, remove the memory chip from the removed PCB and insert into the new PCB.
6. Re-assemble in reverse order. Refer to the wiring diagram in Section 8.1 for connections.
When replacing the cover, ensure no wires are trapped and all wiring is secured. Secure with three screws - do not over
tighten.
7. Test the boiler and carry out the fast calibration as described in Section 5.13.
Note; If the original PCB memory chip is not used in the new PCB the boiler parameters will need to be set and full
calibration procedure is required.
7.9 GAS VALVE – BURNER INJECTOR
Note: The replacement of the gas valve or PCB must be carried out by a Gas Safe registered engineer with the use of a flue
analyser.
Isolate the boiler gas supply and gain access as described in Section 7.1.
1. Disconnect the electrical plug from the gas valve.
2. Remove the gas pipe retaining clip from the top of the gas valve and remove the pipe.
3. Disconnect the gas valve union beneath the boiler.
4. Remove the two screws from beneath the boiler and lift out the valve assembly.
5. Unscrew the injector from the top of the gas valve and transfer the injector to the new gas valve using a new washer.
6. Fit the new assembly and re-assemble in reverse order and test for gas tightness.
7. Light the boiler. (Refer to Commissioning, Section 5.4).
8. Test the boiler and carry out the fast calibration as described in Section 5.13.
7.10 DHW TEMPERATURE SENSOR - Fig. 7.2
Gain access as described in Section 7.1.
1. The DHW sensor is positioned in the hot water outlet pipe to the left of the flow switch, see Fig. 7.2. Unplug the two
connections and unclip the sensor from the pipe.
2. Re-assemble in reverse order with a new sensor.
Pressure gauge
Alpha InTec² 25XE and 28XE - Component Replacement
PCB fuse
PCB
Fig. 7.1
41