Set Appliance State:
Mains Power Off
Set Multimeter to DC Volts 
Use Insulation Mat as required
Selector switch to hot water
DHW Temperature selector to maximum
Selector switch to hot water
DHW Temperature selector to maximum
| WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure |
Measurement:
Measure the voltage across the red (Note: there are two red wires, the red wire for this test is located between the black wire and white wire) and white wires on J6 (black connector) on main pcb.
0V DC should be measured.
Turn hot water tap On.
Repeat test.
5V DC should be measured.
Note:
For these tests it is easiest to connect the probes to the front of the connector where exposed silver connections can be seen,
0V DC should be measured.
Turn hot water tap On.
Repeat test.
5V DC should be measured.
Note:
For these tests it is easiest to connect the probes to the front of the connector where exposed silver connections can be seen,
Isolate as per TOPs P4
and refit as necessary