Noisy/vibrating hot water pipe. All aspects of plumbing questions and answers, help, tips and information

[Gene12]

I have a Worcester 28i combi boiler (sealed system) which is 6 years old and has always been fine. I recently replaced our bathroom and replaced the copper water pipes in the bathroom at the same time to fit the new sink, bath and toilet. Everything was fine until the last week or so when the hot water pipe in the bathroom has started making intermitant tapping noises which get louder but stop when i turn the tap on. The pipe itself feels quite hot and shakes even though the system is not always being used (eg at night) and it sounds as though something (fan?) is going in the boiler even when the central heating and water are not being used. What is causing this and how can I fix it? I've been told it could be water pressure or too high thermostat temp on the water. As this is factory set I do not know how to adjust it. I did not touch the pipework to the radiator when i did this work.
Any help would be greatly appreciated. Many thanks

[bjbiker]

It sound like you have a water hammer problem, try fitting a water hammer arrester on affected pie work.

[h.young.engineer]

hello i am a first year student enginner for haden young. for my first college block i had to design a Low Temperature How Water heating system for a nursery. From what it sounds like the pressure is too high within the pipe. you want to achieve a pressure of roughly 300Kpa (CIBSE reccomendation) as this is the most efficient and has little noise level. The noise could be because the pipes used were of the wrong size or your jointing methods need brushed up (no offence) however as for the fan noise i am unsure if you have a condensing boiler that will be a fan situated within the flue to take excess gases out of the system due to incomplete combustion.