Noise is a hard thing to resolve, being humans we all have different tolerances to types of noise.
The boiler will make a noise, especially when first firing up and working hard. The noise it makes might sound some what strange if compared to other boilers you may have had. Modern fan assisted modulating condensing boilers sound totally different to an old back boiler or older type of boiler. What are you comparing it too?
It shouldn't be making any banging, severe clicking, crunching or bubbling volcano sounds.
Any sound described as a hum, whistle, drone, roar, buzz etc might be normal and as expected, depends on the severity and your tolerance to noise.
Other things can effect the sounds such as resonance, and echo from boiler position in house and the struture.
