Replacing The Main Power Pcb - Heatrae Sadia Amptec Installation Instructions And User Manual

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 first. 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 qualified 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 (Conn 1), the temperature switch connector (Conn 3), and the
thermistor connector (Conn 4).
5 Unplug the power connectors on the elements.
6 Disconnect the main power cable to Conn 5.
7 Remove the 4 pan head screws & washers identified by the black triangles (see fig.16 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 fitting 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 pan head screws & washers.
5 Tighten up these screws in the order shown fig.16. 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 fire.
FIGURE 16 : MAIN POWER PCB
1
3
2
4
21