I can’t fins the answer on google so I’m resorting to the next best thing.

I have a three way tap. Probably this one – don’t know, it came with the house but it was connected to one of their filters.

https://www.silverlineuk.co.uk/water-filter-taps-and-accessories/triple-flow-taps/triple-flow-water-filter-tap-tall-triple-flow-tap#product_tabs_silverline

It doesn’t appear to be working properly anymore. When one tap is turned on (mains hot/cold water or purified) water come out of both holes – doesn’t matter which tap I use. Weirdly the flow changes out of each hole if the tap is moved/rotated. I’d rather not spend £170 on a new one as I’ve just had to replace the dishwasher. I don’t want to take it out/apart without knowing what I’m doing in advance in case I make it worse. Anyone familiar with them and know how to fix it.

Can’t find any info on how they are arranged internally. I don’t know if is internal pipes or metal work up to the outlet?