I want to change my bathroom pedestal basin for a new one. The current one has a single hole for a mixer tap. The first problem is removing this..... underneath the sink there is no back nut for the tap and the copper pipes seem to go directly through the single hole in the sink straight into the taps.... i.e. I cant see anyway of unscrewing the mixer tap from underneath.
If we assume the sink is at waist height.... at knee height are two compression fittings on the pipework, one for the cold feed and one for the hot......then copper pipe directly from the compression fittings into the taps as above Once I manage to remove the existing mixer tap and basin (first question above!!), my new basin will have two holes for separate taps.....
What is the likely fitting at the top of the existing taps? as I say I cant see any bolts etc from underneath. The two current feed pipes are close together (I presume so they can both fit through the single hole in the sink) and I was wondering if the best cause of action would be to cut the pipes above the compression fittings at knee height and then connect flexibly hosing where I cut and then up to the two new separate taps.
The existing mixer taps should fit using either 1 or 2 10mm nuts on threaded bar. You may when the basin is out undo them with an adjustable spanner, but a box spanner is the proper tool.
The copper pipes reduce in diameter to 10mm and the "tap tails" have threaded ends that go straight into the tap base.
I suggest you purchase two inline service valves to fit where the compression fittings are and as soon as these are fitted, you can turn the water back on, so there is no rush to fit the basin.
The fittings to 1/2" basin taps is entirely different to mixer and you cannot use the existing it will need to be replaced. You can use flexi pipes, but understand that if the hot water is low pressure (cylinder and header tank) the flow from the tap may be poor.
Yes, just take the whole lot out in one go then fix the valves and turn the water on.
As you have a low pressure system it would be best to keep the hot as full bore. Use plastic pipe with push fittings if you are unsure about fitting copper. White pipe looks better under a basin anyway.
If you do decide to use flexi couplings check the bore before buying. Some are better quality and have wider bores than others. If the header tank is on legs in the loft, a good flexi might work alright and cold will be ok anyway.
Thanks for your help so far, couple of more things and I'll give it a go..........
So, im going to remove the sink and take off the compression fittings, leaving me with the two 15mm feed pipes. To these I will fit a copper push-fit inline service valve. Above these I will move onto plastic 15mm pushfit piping (can this fit direct to the copper push fit?). As the two feed pipes are close together, I think i will need elbow joints to separate them below the sink as the two new taps are obviously further apart.
Does this sound right so far?
If the plastic piping is 15mm and the tap fittings will be 12mm do I need to buy some sort of reducer or will the taps come with this fitting? Also do I need to use pipe inserts in the plastic pipes? - what do these actually do?
It will be the bath next!! Is this just the same but 22mm tap fitting from a 15mm feed pipe?
Use 15mm compression fitting service valves with the proper inserts on the plastic side. You can use either pushfit or compression elbows for the rest, but inserts must be used on all plastic.
The taps need proper 1/2" BSP ( bath are 3/4") tap connectors available as either compression or pushfit.
If you are unsure, I would probably recommend sticking with flexible pipes as they are easier to connect. Yes there is a risk the water flow on the hot may be reduced, but it's probably worth the risk if you feel wary.
Stop mucking about, and get on with it! Lol. You could be washing in it by now!
If you have 2 service valves, at least you know the water will be easily put back on.