Set Appliance State:

CH Demand
Ensure CH system is cool
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Reset the appliance if required (Press reset button once then release).
Does the appliance recognise the CH demand?
(C and C.Heating Active will appear on the display)
If the demand is recognised does the fan then run?