Kitchen Sink Basket Strainer How do they work

[Diyisfun]

I have one fitted in my sink, it seems to act as a plug & I need to take it out to make the water flow away.
How are they supposed to work. I have a 1.5 bowl

 

[seco services]

It is a plug it has a black seal on the bottom so it seals when pushed fully down.
Lift it up and the sink will drain but catch any crud from going down the plug hole.

 

[Diyisfun]

Mine seems to seal without it being pushed down.

 

[seco services]

Has it still got the ball bearing half way down the stem ?

 

[Diyisfun]

it has a black rubber thing half way down the stem
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Do they do them for standard plug hole size?

 

[sooey]

Lift the centre part slightly and twist it, it should then be in a slightly higher position to allow the water out, twist it again to close.

 

[seco services]

it has a black rubber thing half way down the stem

not the type with the ball bearing ie mcalpine.

Do they do them for standard plug hole size?

Useally only the 90mm waste.

 

[Charnwood]

You can get a couple of types of strainer that will fit standard 11/4" and 11/2" plugholes, but they have to be removed if you want to put the plug in.