Set Appliance State:

Mains Power Off
Ensure NO demands are present
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Reset appliance.
Does the boiler reset?
Note:
1. If after boiler reset the fault code changes from the original to a different fault code, then CLICK HERE.
2. If fault code is a recurring issue, then choose "boiler does not reset - fault code remains the same" to investigate possible causes.
3. Reset is confirmed by the boiler returning to the "normal display". On some appliances the pressure may also be displayed on a "normal display".