Overflow pipe leaking require advice

[Raff]

Hi I noticed yesterday water pouring out from a pipe from the top of our house its leaking water over the garden and its on and off occurring.

I think its the overflow pipe since it appears connected to the water tank in my attic, so I made a trip up there and moved the top cover of the water tank (appears just one large tank up there) and on the inside copper valve? is a white plastic part on top which is leaking non stop with water.

I did push the float down and water came thru it well and reached the overfill entrance pipe to the tank and water came outside the house again and then noticed the leaking stopped once I let go ?

Here is the picture of the copper valve and white thingy on top dispensing the water:
hxxp://oi59.tinypic.com/1554e3s.jpg

(sorry board not allowing post of link replace hxxp with http)

While its stopped leaking I take it life is never this easy?:sweatdrop:

Can I simply switch off the 2 taps connected to my water tank to stop water from going in there and use a wrench and buy that valve/white plastic part to stop it from leaking to fix my bacon ?

Any advice on the terminology on parts since if I ask for a white thingy I may get something else....
thanks

 

[Dotty]

Go to b&q. You need one of these.

PlumbSure Universal Ballvalve Kit, 0000003892879

 

[Chalked]

Or a complete valve.
Part 2 Float Valve Brass ½" | Float Valves | NoLinkingToThis

 

[Centralheatking]

hey Jon u still on call or maybe not
I think because your being so nice

rob

 

[Dotty]

Off call now Rob. Working in Belfast today, home now with a beer and waiting on my jalfrezi to show up.....

How goes it with you?

 

[Centralheatking]

I will email you now mate all is good CHk

 

[Dotty]

I won't see it until the morning buddy.

Littl'un has commandeered the pc for tonight....

 

[Raff]

much appreciated for all the help guys !

I am thinking rather then replacing the washer and bits inside just get it replaced fully since its cheap like 8 quid
The 2nd one linked has some negative comments about being cheap and not lasting some suggested the peggler brand this one I think:

hxxp://www.NoLinkingToThis/p/pegler-prestex-float-valve-part-2/27627

This one any good? looks the same as mine and sounding from the useful comments the leak is most likely coming from the part 2 bit and not the other connecting pipe on the other end so could just replace it?