noisy tap (really noisy!!) - help please

Nikki

Hiya,
I was wondering if anyone might be able to solve the problem I have with a very noisy cold tap. Its only the bath tap which seems to be a problem - the sink taps in the bathroom and kitchen are fine.
When you turn the tap on there is this almighty groaning or humming noise - its so loud that my neighbours must be going demented
We recently had a new combi (condensing) boiler fitted which seems to have made the noise a bit worse.
Anyone have any ideas what could be causing it and how we go about fixing it?
Thanks

biking4jesus

is the sound just moaning or more like banging in the pipes. if its more of a popping or banging noise then you might need a water hammer arrestor. http://www.plumbersurplus.com/ProductList.aspx?Cat=240

Nikki

sorry for the delay in replying.
The noise is not a banging - its just a really loud groaning/screeching/moaning. When its making the noise you can hear it kind of vibrating through the pipes and the more you trun the tap on the noisier it gets - although sometimes if the tap is running and then you start to turn it off it also starts making the same noise.
Any ideas?

Re the banging - I have a radiator that ticks all the time - would that be due to air in the system (even though I have bled the radiators on numerous accasions - whilst hot and whilst cold) or is that water hammer?

On another note - does anyone have any idea how you get central heating restorer into your system when you have a combi boiler? We should have done it before replacing the boiler and put it in through the expansion tank but weren't able to as the system was already drained and off. The gas fitter who did the boiler said to put it in through the radiator but how?

Thanks