Set Appliance State:

CH Demand
Ensure appliance is cool
CH temperature control turned to MAX
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Reset appliance if required.
Observation 1.
Does the appliance recognise the CH demand ?
A Radiator symbol will appear on the display.
Observation 2.
If the demand is recognised does the fan then run ?