Hi .. i have a problem with the flue of my Biasi Combi Boiler .. whenever the heating is switched on - or if the hot water tap is turned on - the flue "honks" or "hoots" .. it usually does about 4 short honks followed by a longer 5th honk - and it does these honks twice before stopping. It's driving my neighbour mad and his threats are getting worse !!! the boiler had previously "rumbled" after the heating had been on for a while (or if I turned the hot water tap on and let it run slowly whilst the heating was on) - this was finally repaired (a tear in a plastic pipe inside the boiler) and rarely happens now but since that repair I've had the honking problem .. boiler man who repaired the rumble - and he in turn created the honk - won't come back out to sort !!!