User guide

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11.0 REPLACING THE MAIN POWER PCB
Note. Before any maintenance is carried out on the system, ensure that the electrical supply has been
disconnected rst. Care must be taken as the water may be scalding hot and at high pressure.
Maintenance on the boiler can only be carried out by a qualied and competent tradesman in accordance
with supplied instructions.
Removal of the Main Power PCB
1 Switch OFF electrical supplies to the boiler. Both Main, “Live and Neutral”, and Control “R and N”
must be isolated
2 Remove the front top panel.
3 Disconnect the control PCB and carefully remove the high temperature insulation and the
front bottom panel.
4 Unplug the control connector (Conn1), the temperature switch connector (Conn3), and the
thermistor connector (Conn4).
5 Unplug the power connectors on the elements.
6 Disconnect the main power cable to Conn5.
7 Remove the 4 screws identied by the black triangles, see gure fourteen below.
8 Carefully remove the PCB assembly from the pipework. This may be stiff and gentle prising at the
top may be required.
Replacing the Main Power PCB
1 Ensure heat sink compound is used on the heat sinks.
2 Identify and plug the power connectors onto the elements, colour for colour, as it is easier to make
these connections before tting the PCB.
3 Holding the back plate line up the pillars with the PCB and position it onto the pipework.
4 Loosely add the 4 xing screws.
5 Tighten up these screws in the order shown below in gure fourteen. It is important to ensure that
the PCB assembly is tight on the pipework.
6 Reconnect the control PCB and replace the high temperature insulation.
7 Ensure the main power connections are tight. Loose connections can cause a re.
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FIGURE SIXTEEN: MAIN POWER PCB