1/4 turn mixer taps, wrong orientation?

keystone

Did you have the iso valve open more on one side than the other and you may have got some carp in it which you have now cleared.

Alternatively the cartridge that is providing poor performance is possibly nerfed and perhaps you'll be needing a new one.

Its only convention that the hot is on the left. That convention is primarily for blind people. Its not a regulation.

Cheers

alinwales

There was probably some rubbish somewhere... when I took the carts out they appeared absolutely fine.