Set Appliance State:

Mains Power Off
CH Demand
Mode Selector Switch to C/H position.
Central heating thermostat to maximum.
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Observation:

Run central heating for a couple of minutes and monitor that the system pressure remains steady (no dramatic pressure rise) on the boiler pressure gauge.
The initial system charge pressure must be within the blue area of the gauge at all times. This corresponds to a system pressure in the range 0.5-1.5 bar.