Set Appliance State:

Mains Power Off
After power OFF, wait 15 seconds before power ON
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

After following the above procedure has the fault code reset?
L5 fault code has reset, but the boiler now shows a different fault code CLICK HERE
L5 fault code cannot be reset CLICK HERE
L5 fault code resets but you would like to confirm the operation of the boiler CLICK HERE