bath taps no pressure

[mickqc]

after fitting some bath taps as part of a bathroom refit on to a traditional vented system.
the taps were said to be okay for systems down to 0.5 bar but the flow rate was poor.
we only had 2.2m from taps to bottom of header tank so i changed them to ones that could operate down to 0.2bar.
I could not tell much difference myself but the customer was happy.
why can some bath fillers operate at lower pressures than others??

 

[SimonJohns]

The double check valves restrict the flow. So having taps without them can work at lower pressures

 

[mickqc]

do they sell taps without check valves

 

[mickqc]

oh sorry i get you, you mean the pair that work at 0.2 bar don`t have check valves on.
as i said i didn`t notice much difference.

 

[mickqc]

would individual bath taps be better and what kind of pressure can they go down to as there isn`t check valves in these so they should just flow freely.