Observation:


Tests indicate the integral fuse on the PCB has blown, this
component is designed to protect the low voltage area of the PCB.
The failure may have been due to fatigue on the fuse or a short
within the PCB, however, it is often caused by a short circuit
from a water leak within the appliance or component failure.
Inspect the boiler for any signs of water leaks, short circuits which may have
caused component failure, components to check are but not limited to;
  •   Fan assembly
  •   Water flow sensor
  •   Thermistors
  •   Wiring harnesses (e.g. signs of damage, short circuit)

    If any additional faults are identified they must be rectified before the PCB is replaced.
    Note:
    The fuse may differ in appearance but will remain in the same location.