Flexible hose size for toilet cistern

[Slider_0809]

Hi

I need to buy a flexible hose to go between my toilet cistern and the 15mm chrome feed pipe. I note there appear to be two common sizes, ½" and ¾". Are all toilet feeds the same size?

 

[londonboy123]

toilets are usually 15mm (1/2") BUT flexy pipes to feed a WC cistern is really only suitable if the toilet is supplied from mains pressure (eg/ a direct system)

 

[Slider_0809]

toilets are usually 15mm (1/2") BUT flexy pipes to feed a WC cistern is really only suitable if the toilet is supplied from mains pressure (eg/ a direct system)

Thanks for that. Toilet feed is from mains (direct) - I think!!! If I turn the main cold water stop cock off under the kitchen sink ALL cold taps in the house stop. Seems only the shower is fed from the cold water tank in the loft. Is this what's known as a Direct system?

Out of interest, if I had an in-direct system why is flexible pipe not really suitable?

 

[londonboy123]

yep you have a direct system with the cold tank in the loft feeding your shower via the hot water cylinder.

flexy pipes are not suitable for toilets on indirect systems as the presure is of course lower, flexy pipes restrict the flow and as it may be ok for a tap (basin/bath etc) to be fed from a flexy pipe under tank pressure, a toilet is different as not only does the water have to flow through a restricted flexy pipe but also has to push through a float valve diaphragm!! the pressure will be too low-better off using rigid copper pipe in this case!

as yous is main presure though (a direct system) then it is fine!!

 

[Slider_0809]

yep you have a direct system with the cold tank in the loft feeding your shower via the hot water cylinder.

flexy pipes are not suitable for toilets on indirect systems as the presure is of course lower, flexy pipes restrict the flow and as it may be ok for a tap (basin/bath etc) to be fed from a flexy pipe under tank pressure, a toilet is different as not only does the water have to flow through a restricted flexy pipe but also has to push through a float valve diaphragm!! the pressure will be too low-better off using rigid copper pipe in this case!

as yous is main presure though (a direct system) then it is fine!!

Thank you