Noisy boiler

[Fee_B77]

My combi boiler (Ferroli or somethin or other) occasionally makes the most gawd awful banging noise. It starts of slowly then gets faster and louder then it kind of whooshes. The pressure gague shoots up and it sounds like it's going to blow. Should I be scared?

[buildersmate]

It sounds like the water is kettling - boiling inside the boiler heat exchanger. If the pressure gauge also shoots up you should look to see if there is evidence that the pressure relief valve has released excess pressure by water coming from the overflow pipe. I'm afraid it sounds like a plumber needs to look at it.