has anybody had problems with this boiler, any known faults. has just gone out of warranty, had to have new pcb and fan as heat exchanger leak led to boiler lock out and when b.gas serviced for 1st service to go plan with them co2 reading off the scale. lucky boiler is in garaged with vertical flue as consequences are not worth thinking about, still locking out, phone baxi who say no known probs with this boiler, but experience and wallet tell me otherwise. needed pcb as voltage not constatnt and think leak has jiggerger pcb on fan any comments welcome