Ballcock valve needing replaced

[Ian barrie]

Hi, I've just bought a house and the overflow pipe from cold water tank was running. So I am trying to replace the ball cock mechanism. I bought what I thought was the right one from b&q - but the thread was too small. So I now have the valve off, and will take it to b&q tomorrow to look for a replacement but would be grateful for tips. Happy to share pics

 

[Deleted member 120897]

Afaik it should just be part 2 float valve, which are usually 1/2” thread.

 

[ShaunCorbs]

Might be a 3/4 one seen a few the thread od should be around 1” dia for it to be 3/4 or on 1/2 should measure 3/4” od