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.
Gas On
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Measurement:

Measure Mains Voltage across the Yellow Wire
(connected to the Green Neon) and the Main
Appliance Neutral.
Note:
Please remove the Boiler Facia before carrying out test.