Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Gain access to front control PCB (use insulation mat as required)
Disconnect external controls connector X9 in programming unit, make safe
No demands
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

With X9 connector disconnected does the pump still run continuously and / or does the boiler attempt to fire after self-check has completed?