Plumbing questions - noisy cold water tank

[Drive Blind]

Hi - need some guidance please,

My cold water tank has suddenly become noisy when it fills up. I'm guessing the float valve has become faulty or worn and will need replaced?

However, due to the set up - cold water tank positioned above the hot water tank both inside a cupboard - there is very little access to the top of the cold water tank. I can barely get my hand up there. Do I need to dismantle and remove both the hot and cold water tanks to gain access?

This sort of project is well beyond my limited diy knowledge and skills. Or is there some trade secret to get access?

Also whilst having a google on this problem this morning a few websites mentioned the average life of a hot water tank is 10-15 years. Mine is now 22. If I need to remove the whole lot to get access to the float valve should I be looking to replace the hot water tank whilst I'm there?

Cheers for any advice

[redeye]

when you say noise what type of noise (hammering)

[Drive Blind]

no it's not a hammering or banging noise

it's more a sort of whistling which changes note as the level of the water falls and rises again. Also when its at it's noisiest when running a bath you can hear the flow of water (although no where near as loud) in the kitchen. I assume the kitchen is where the water main comes into the flat.

I've been in the flat 8 years and it's been fine up until 2 weeks ago.

[Deva Link]

Does your cold water pressure appear to have changed recently? You could try closing the stop-cock a bit and see if that helps.

[Drive Blind]

no noticable change in water pressure.

I asked my neighbours if they were having any plumbing issues and they all said no. They have the same plumbing layout. 4 flats in a block.