Set Appliance State:

Mains Power Off
Turn Hot Water Tap On
Allow appliance to cool
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Reset appliance if necessary (tap middle button on the fascia).
Does the appliance now run and burner ignite
or does the fault code reappear?
Note:
It make take up to 2 minutes before fault code reappears.
CLICK HERE IF A DIFFERENT ERROR CODE IS NOW SHOWN