Set Appliance State:

Gas Off
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)
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Measurement:

Allow boiler self check to complete.
Hold down the spanner and ECO buttons for at least 5 seconds to enable service mode.
(MAX should be shown at the bottom of the display).
Measure the voltage across the brown and blue pins marked 5.5 and 5.6 at X11 connector on the PCB using the test pins above the connector.
Mains voltage expected.