Understanding biidet plumbing

[Traveller4371]

I have a rim/spray bidet (Armitage Shanks - which dates to about 1988. It is basically in good condition and I don't want to replace the whole bathroom suite.) A lever changes between rim and vertical spray, and another small knob opens/closes the drain. I want to service the mixer tap/popup drain system, which seems best done by removing the whole bidet.

Looking at the hot and cold water inlets (low pressure direct feeds) I find that the 15mm copper pipes have soldered tapers immediately before they enter the bottoms of the taps. However, the size of the compression joint nut seems to be a standard 15mm size. I tried to photograph the plumbing to aid understanding but I could not get a camera in a suitable position - too near a wall!

Does anyone know why the tapers are required?

Comments appreciated.

 

[jonnyswamp]

These will be semi rigid copper tails with a 10/12mm thread on the end which screws into the base of the taps
What type of taps have you got, quarter turn with ceramic discs or full turn with rubber tap washers, either way the taps shouldn't need to come off to replace washers or whole cartridge depending on which type you have
Post a pic or two

 

[Traveller4371]

Thanks for your reply.

If the taps have a 10/12mm thread, why does the nut on the connecting compression fitting seem to be of the standard 15mm size - perhaps that is normal? I am asking this because I want to understand how to seal off the pipes if I remove the whole bidet.

I have full-turn valves with and have already replaced the complete valve inserts in both taps. I had a problem getting one of them unscrewed but have now succeeded. What I now need to do is service the popup drain which is difficult to turn/operate (maybe corroded?), and when the rim/spray lever is turned to "rim" there is evidence of a very slow or occasional drip from the bottom of the lever unit. Presumably this will only get worse.

The mixer tap unit is no longer available (as far as I can see) so my only option is to take it all out and thoroughly service it.

 

[AlexGas]

The mixer tap unit is no longer available (as far as I can see) so my only option is to take it all out and thoroughly service it.

Hope it goes well. Please keep us posted.

 

[Masood]

If the taps have a 10/12mm thread, why does the nut on the connecting compression fitting seem to be of the standard 15mm size - perhaps that is normal?

Yes it is normal. Standard pipework size is 15 or 22mm but monobloc tap tails are smaller in order to keep the overall tap size manageable. Hence the tapered tails to achieve the size reduction required.

 

[Simon F]

If the taps have a 10/12mm thread, why does the nut on the connecting compression fitting seem to be of the standard 15mm size - perhaps that is normal? I am asking this because I want to understand how to seal off the pipes if I remove the whole bidet.

if you need to cap for a time, then just cap the 15mm??
using either a standard 15mm stop end or a cap

Stop End 15mm Pack of 2 | Compression Sundries | NoLinkingToThis
Compression Blanking Nut 15mm | Compression Sundries | NoLinkingToThis