We have a combi boiler, and recently when you run the shower after turning the hot tap off there is a large banging in the pipes. It only seems to happen with that specific tap (as far as I can tell).
I read online about water hammer, and I think that could be what's happening. I think I might need to turn of the water supply and drain the system, but I'm not sure if I need to turn the taps off/on in a certain order?