Set Appliance State:

Mains Power Off
Set Multimeter to AC Volts Set meter to measure AC Volts
Boiler Thermal Store must NOT be at maximum temperature.
Models with Programmer: Rocker Switch to Continuous.
Models without Programmer: Rocker Switch to On.
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Measurement:

Measure Mains Voltage across Connection 2 (on the 5 way Terminal Block) and Neutral (Connection 1 on the 5 way Terminal Block).