Poor water pressure

[paris28]

I want to replace my bath with a walk in shower but the hot water which comes out my mixer taps on the bath has very low pressure. if you run the hot water for more than 10 mins it grids to a virtual halt. Is this something to do with the pipe work as we get reasonable flow at the basin.

 

[ChrisR]

DO you leave the basin running 10 inutes though... or do you mean the basin is OK after the shower has stopped producing HW?

Details of HW system please.

 

[paris28]

the water in the basin is fine even after the water in the bath stops running. I have a simple over the bath shower from the mixer unit but when the cold water is turned on 1/4 turn the water mix goes cold.

 

[meldrew's_mate]

Are both hot and cold at low pressure i.e tank fed, not mains?

Have you checked the ballcock on the main tank, if it's not filling properly you may be running out of pressure because the tank level has dropped to almost the bottom. Equally the pressure head at that stage may be down to less than 0.5m, which would cause your shower to underperform!

Check the nozzle in the ballcock for debris.

If it's this you can improve it a lot by raising the height of the main tank by as much as is practicable.

 

[paris28]

Both bath taps are fed from a tank. the hot is supplied from a copper cylinder within about 2ft of the bath tap. I have checked all valves and replaced the copper tank in an effort to cure the problem.
the basin has a cold supplied from mains