My Baxi 105 is showing no faults but will not start up?

Electricity at our home was off for over 12 hours. Wewere told that if we plugged out generator into a socket in the house it would run the lights etc. Unfortunately it has blown the boiler. We have already replaced several parts, PCB,or Flue overheat thermostat, safety thermostat, temperature sensor, pressure switch, cable selector switch/pump, cable integr timer and sensing electrode lead. The fan is working and it is trying to start but cuts out. No fault lights on.