No pressure when hot water tap cold

[Viscount999]

Hi all
Wonder if anyone can help
Recently my hot water taps throughout the whole house lose pressure and doesn’t run if the water has gone cold. Once the boiler is on and heated up I have pressure and hot water again.
This doesn’t affect my cold water tap
Any ideas what could be causing this and anything I can do or will it be a case of calling someone in?

 

[Deleted member 120897]

It would help to know what type of system you have, as in combi boiler, heat only boiler, unvented cylinder etc.