Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Gain access to PCB (use Insulation Mat as required)

Observation:

Confirm, inspect boiler for;
  • PCB connections are correctly fitted.
  • Boiler connections to sensors, fan, pump etc are correctly fitted.
  • Check for water ingress on to PCB and/or boiler connections.