Set Appliance State:

Mains Power Off
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Reset the boiler (If it will not reset select that option below
as appliance will not go into service mode while in a fault code).
Set the boiler into service mode:
Turn both DHW and CH temperature control knobs to minimum.
In one continuous movement, turn the DHW control knob approximately 90° clockwise then back to minimum, back 90° clockwise then finally back to minimum again.
As confirmation the boiler display will alternate between "SF" and the flow temperature.
Does the fault code reoccur as the appliance operates in service mode?
(Allow approx 30 seconds after burner ignites to determine if fault code reoccurs).
If a DIFFERENT fault code occurs click HERE to return to the fault codes page.
If NO fault code occurs click HERE to continue fault diagnosis.