my boiler is making strange noises

[trixie1969]

Basically, when my central heating comes on or I switch the hot water on, this loud rumbling noise starts coming from the direction of my boiler. With the central heating, it tends to die down after a while, but with the hot water, it's a bit more constant. Is there anything I can check or do myself to sort it out? Thankyou!!

[pilotlight]

trixie, Make and model of boiler will be required before any advice can be given.

[stanleyman]

As Pilotlight says it would be very helpful to have more info but this could be "kettling" similar to boiling a kettle. This is slow moving water in the boiler being heated too quickly and boiling locally. There are several ways to cure it such as speeding up the pump, fitting or opening a bypass or reducing the boiler output if overfired. Oil fired boilers can benefit from a flame deflector. This can also be caused by rust or scale build up inside the boiler waterways and an additive may help.