Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to AC Volts Set meter to measure AC Volts
Gain access to PCB (use Insulation Mat as required)
Disconnect plug from diverter valve and make safe
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Measurement:

Reset appliance as necessary.
Test 1:
Measure the voltage across the pins marked 4.1 and 4.4 on X7.
Test 2:
Measure the voltage across the pins marked 4.2 and 4.3 on X7.
Voltage on both tests should be approximately 20V AC but
will be varying by up to 5V AC constantly during the test.
Note:
Voltages will only be present for approximately 15 seconds from when power is turned on to the appliance or the appliance is reset, repeat the test as necessary to ensure correct measurements.
If you will not be able to test the PCB within 15 seconds of turning the mains power on click here for an alternative test.