Bathroom hot water sink tap. Low flow

[Julsie]

Hi,
Just had a new bathroom fitted and have a pathetic flow of hot water from the sink tap. It wasn't great before. I can't get hold of a plumber, but any ideas as to what this might be? I also noticed that the pipes that feed the hot tap go into the loft? I know nothing about plumbing, but is this usual?

 

[fowlerboi]

Do you have a water cistern in the loft that feeds a hot water cylinder?

Did you supply the taps?

Its highly likely that you've got a low pressure gravity system with a high pressure tap. Failing that I've had debris get into the isolation valves which slow it down a lot while looking like its just a gravity issue.