Outside tap non-return valve

[Melchett]

Hello all, I'm after some advice for fitting an outside tap. Do I have to have a dedicated drain for the NRV? In the winter, could I not shut off the supply to the tap and leave the tap open to protect the NRvalve from freezing?

Also, can anyone recommend some 10-15mm flexible pipe to use from the supply? Will central heating pipe do? The reason for this is that my supply could not be further from the outside wall so I have to run the pipe behind the skirting. I dont want joints in the wall in case of leaks so copper is out. I wanted to use a single length of plastic pipe. Any sugegsitons?

Ta

[Ricky_M]

Water regs state that outside taps should have a non-return valve fitted, apparently taps with them inbuilt will not suffice!

Very rarely see this happen though.

I always (when possible) install outside taps by fitting the wall-plate elbow upside-down with an isolation valve inside the house.

This way the water pipe is above the tap, so when isolated you can open the tap and all the external pipework is drained.

As for pipe, Hepworth and Speedfit plastic pipe is suitable for cold, hot and central heating, so it will be fine.

[Simpo Two]

Ricky_M said:

As for pipe, Hepworth and Speedfit plastic pipe is suitable for cold, hot and central heating, so it will be fine.

Would they survive freezing? I have 15mm copper pipe outside and always have to keep an eye out for frost so I can drain it to stop it splitting.


As for an NRV, that's the tap!

[Deva Link]

Ricky_M said:

I always (when possible) install outside taps by fitting the wall-plate elbow upside-down with an isolation valve inside the house.

That's a good idea I'd never thought of! I turn them off while flowing and hope the water will all run out.

[Ricky_M]

Simpo Two said:

Would they survive freezing? I have 15mm copper pipe outside and always have to keep an eye out for frost so I can drain it to stop it splitting.


As for an NRV, that's the tap!

I was under the impression he was running pipe inside the house, behind the skirting because it was to be fitted a long distance from the supply?

Some taps have NRVs built in to them, but pretty sure the Water Regs state that there must be one installed on the supply pipework to the tap.

[Melchett]

Yep, most of the pipe will be inside the wall so only the tap will be outside. I have seen some taps that dont use an elbow so all the pipe will be in the wall. I'm not sure which sort of tap to use yet but the least amount of pipe outside the better.

[Ricky_M]

That type is more attractive, but when you are drilling your hole. Drill from the outside in with the smallest bit you can.

The screw holes are very close to the centre and if you break away outside or use a drill bit that is too big, you'll have trouble securing it too the wall.

Also just noticed something in your original post. Don't use 10mm pipe, the flow rate will be dreadful!

[Melchett]

Ricky_M said:

That type is more attractive, but when you are drilling your hole. Drill from the outside in with the smallest bit you can.

The screw holes are very close to the centre and if you break away outside or use a drill bit that is too big, you'll have trouble securing it too the wall.

Also just noticed something in your original post. Don't use 10mm pipe, the flow rate will be dreadful!

I thought the taps internals were 10mm, so it wouldn't make any difference. I take it the taps are 15mm? Is the difference that noticeable?

[Ricky_M]

The tap internals will be small.

But it will have a 1/2 inch thread on it, which is equivalent to 15mm in pipe sizes.

I've never used 10mm on a cold water supply. I really don't think the end result would be great.

[Melchett]

I have just found another problem. The feed I planned on using was that for a downstairs toilet, which is also 10mm. If I can't find a larger feed I will be stuck with 10mm.

[Ricky_M]

Are you sure that it is not 15mm? Very unlikely that 10mm has been used on the cold water supply.

[netherfield]

http://www.screwfix.com/p/comap-hose-union-back-pl...

This makes a neat job,fix the tap on first so it sits vertical.

Some outside taps have a bung underneath so you can drain the water out in winter.

[Melchett]

Ricky_M said:

Are you sure that it is not 15mm? Very unlikely that 10mm has been used on the cold water supply.

Yep, it is definitely 10mm. I have checked all the other bogs in the house and they are also 10mm.

[Ricky_M]

That is odd! Still, no real reason why you can't run your tap off 10mm. It may take a while to fill a bucket though!

[Deva Link]

I would guess 10mm would be OK - after all, if you use a hosepipe there are all sorts of connectors of restricted diameters involved.

If using CH pipe though, its internal diameter might be pretty small if it's barrier pipe. I would also be very cautious about not kinking the stuff (especially non barrier pipe) while installing behind skirting if you need to go around corners.

Don't forget to use internal support sleeves at the connectors - one of them blowing off with mains pressure behind it wouldn't be funny!

Edited by Deva Link on Monday 2nd May 21:47

[Melchett]

Deva Link said:

If using CH pipe though, its internal diameter might be pretty small if it's barrier pipe. I would also be very cautious about not kinking the stuff (epecially non barrier pipe) while installing behind skirting if you need to go around corners. !

I need to go around two corners, I was hoping to increase the radius of each one but how flexible is this stuff? I want to avoid joints/elbows behind the skirting just in case.

[Ricky_M]

You wont get it round a tight 90 degree bend. The fittings are quite chunky also.

10mm copper comes in coils up to 50 metres, you could quite easily run that and not require any joints, you can also pull tight 90 degree bends using a hand bender.

[Simpo Two]

Melchett said:

I dont want joints in the wall in case of leaks so copper is out. I wanted to use a single length of plastic pipe.

Seems that plastic pipe is going to need elbow connectors for the bend, so you may as well go back to copper and use solder elbows. I don't think you'll get anything more reliable.

[Melchett]

One last quickie, is it possible to get 10mm compression fit (not push fit) isolation valves and NRvalves? I can find 15mm on screwfix, but not 10mm.