Things to look out for

Water pressure
If your water pressure is too low it won’t cause any damage, but it will affect the efficiency & effectiveness of your boiler – so you’ll be paying more in energy bills.
The standard operating pressure is usually 1 – 1.5 bars of pressure. Anything above or below that will need to be repressured.

Water flow
If you have poor water flow, the water could get stuck in the boilers heat exchanger. So, when the water starts to boil, steam & expand the boiler will make a noise like a boiling kettle, and have a slight whistle. This is very common in older boilers or central heating systems.

Incorrectly set thermostat
If your thermostat is set too high it could cause a boiler to become very noisy. Try lowering the temperature on your thermostat, so your boiler isn't constantly running too high and working too hard. This should help your boiler stay quiet.

Limescale
A build-up of limescale will cause steam bubbles to be produced, which will make a loud noise like a kettle boiling. Limescale has a significant impact on the lifespan & energy efficiency of a central heating system.
To fix the issue we'd recommend getting a gas safe engineer to administer a chemical descaler or flush to clean up the pipework and get rid of the build-up of limescale within the system.