Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Disconnect any external controls at terminals 7 & 8 of
connector CN6 and make safe
Fit wire link between terminals 7 & 8 of connector CN6
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Does the boiler now respond to a CH demand (radiator symbol)?