Noisy new float valve in loft

You may want to insert an in-line service valve in the pipe. Open the ball valve fully and see if the overflow can take the flow. If the flow is too high then reduce to suit. If a valve goes then you will have a rather wet ceiling which may come down if it happens when you are out, as the overflow can't cope,

I agree that service valves are a Good Thing (the plumbing in this house had NONE grrrr), but in this case I think I'll leave it.

The overflow is quite fat & steep, and coped with a very knackered float valve. Besides, looking at the mechanics of the thing, even when the valve failed the pressure was still reduced quite a lot as the float arm was floating and restricting the flow into the tank.

If that makes any sense.

Jeremy I think Christian, in his posting, gets to the source of your problem. Your original kit may have had a, probably brass, filler tube going below the surface, so you would not have heard much filling noise. You can't get them any more as they break the water bylaws because of syphoning. The new way, as Christian mentions, is for a long flacid plastic thing to replace the open brass filler pipe. Paul

Jeremy I think Christian, in his posting, gets to the source of your problem. Your original kit may have had a, probably brass, filler tube going below the surface, so you would not have heard much filling noise. You can't get them any more as they break the water bylaws because of syphoning. The new way, as Christian mentions, is for a long flacid plastic thing to replace the open brass filler pipe. Paul

Fit a 'Henson Delay Valve' it will cure your problem and cure water hammer. Can be got from e-bay

Nothing like good impartial advice, 12 years after it was requested. ;-)

Tim

Perhaps his computer has a Henson Delay valve fitted.

G.Harman