I just changed the jumper valve on a bathroom sink cold tap which was dripping and now the pressure has dropped on both the cold tap and the hot tap paired to it. I have dual sinks and the other still has good pressure.
The old jumper value was brass and I would say original (12 years) the new one I bought from you was 13mm jumper valve.
I have change quite a few over the last year or so and this is the only one to lose pressure
