Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Remove boiler case if you have not already done so
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Boiler will do a self check whenever power is restored to the boiler (AP shown on display).
For two minutes the boiler should operate as below:
  • Fan runs constantly (fault code displayed after short period if it does not)
  • Pump runs at 5 seconds intervals
    If the boiler detects a fault during this time it will interrupt the self check and display the code.
    Self check is complete when the display changes (system pressure or fault code shown) and the fan / pump stop running.