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Pipes make very loud bangs when i flush the downstairs toilet. Most of the time, it is just one bang but occasionally, bangs go on for almost 30 seconds or so. To be precise, I think bangs happen when the cistern is filled or when it starts to get filled, very hard to tell but it's one of those!

My boiler is losing pressure daily i see no obvious leaks accept one radiator that needs a replacement valve/thermostat I've isolated this radiator the pressure is lasting long but still losing

I am confused? I have had 4 quotes for a new combi boiler. Two of the quotes say I new a pipe upgrade and Two say I don't? My boiler is in an off shot galley kitchen (next to a normal gas cooker). The floor distance from the meter (in the cellar) is approx 10/ 11mts. There are a couple of bends that take the pipe from the cellar to the kitchen. The pipe is 22mm all the way. I have looked at a 24kw Ideal basic Boiler and a 30kw Ideal Logic Max. Which company should I believe?