Set Appliance State:

Mains Power Off
Gas Off
CH Demand
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Observation:

Press reset button allow boiler to reset.
Switch boiler control switch to L position.
Allow fan to run for 1 minute then observe display on control box.
Note:
Fan speed may oscillate from high to low speed during test period.
As gas is off boiler will not ignite and display may show 'F'.