Fitting new W.C

[jshaw300]

I would be really grateful if someone could help me understand this -

My bathroom has a concrete floor and so all the pipes are visible. I'm looking to replace my toilet and have examined the pipe layout.

The cold water pipe for the bath taps branches off and then feeds the w.c. This is what I would have expected. However-

A pipe comes up from under the floor and connects to the cistern. This pipe has a tap on it. The cold water pipe from the bath branches into this pipe above the tap.

My question is what is the pipe coming through the floor? I cannot trace it as the floor is solid concrete. I would have thought that the pipe coming from the bath feed was enough?

Any help/ suggestions appreciated.

 

[Bahco]

Is the pipe in question not your incoming rising main feeding your wc and bath/basin.
When you say it feeds your cistern is that your wc or loft cistern

 

[jshaw300]

Thanks for taking the time to reply. Just after I posted, the penny dropped. I think this must be the rising main. I cannot turn the tap, so I have not been able to test this theory, but it makes sense.

Any ideas for a stuck tap now!?

 

[Bahco]

Add penetrating oil every day and try to move slightly every time back and forth .
May free it over time

 

[mrcrow]

shut off at mains and fit a neat little valve before the old one if you can...
i had an old valve and the stem sheared as i tried to ease it.
if you are shutting off mains for any other reason etc its not a double task.