Outside Tap

Nazbit · 16 Mar 2016 at 20:44

Hi,

We've got an outside tap and it is working but the flow is pretty low and always has been.

In the picture the spur on the left is the outside tap, the next one along is the cold feed to the kitchen sink and the one on the right is the hot feed to the sink.

The sink has a flow of 520 litres an hour on the cold feed, so that's my baseline of what's possible.

The limitation seems to be the tee junction with the shut off valve, it's 15mm pipe but internally the junction to the bottom spur is very narrow.

I need to achieve a flow of 500 litres per hour outside, 600 would be even better but unlikely.

I'm thinking replace the tee junction with a proper tee compression joint and then run some 15mm pipe but step it up to 22mm and install a full bore 22mm isolation valve and a 22mm full bore double check valve. Is it worth doing this step up in order to minimise the obstruction that the isolation and double check valves will cause?

Then I thought either replace the existing 15mm tap connector with a 22mm full bore (19mm) one, which will hopefully give me a similar flow to the sink of about 500 litres per hour despite the resistance of the various valves.

Or even replace the flexi tube with copper pipe reduced from 22mm to 15mm once the valves are cleared, that might allow me to exceed the 500 litres per hour seen at the sink as that is through the 15mm flexi connector.

Will I get decent flow from this set up?

How restrictive are the double check and isolation valves likely to be? Is it worth going for large bore 22mm valves instead of the 15mm which seem to go down to 10mm or less internally?

Thanks

Edit - oh and the current outside flow is 180 litres an hour

FlyingFish · 16 Mar 2016 at 23:35

Proper diy plumbing in the pic m8

Anyway, if your getting the desired flowrate from the kitchen tap, that is plumbed up as shown in your picture, then I would whip out the outside tap isolation tee and replace it with a 15mm compression tee and screw the flexible pipe straight into the end of it. Instead of using the nut and olive.

Then do a test to see if you can obtain the desired flow rate.

If not then look at replacing the hose for 15mm copper and possibly the outside tap.

Once you have the desired rate, just add an isolation valve. Ideally this would be a stop tap, but if flow is critical you could fit a gate valve, but they are not really designed for mains. They do have less internal resistance tho.

Moving up to 22mm shouldnt really be necessary, especially if like you say the kitchen tap can manage good flow on those flex hoses in the pic.

Mick

Hedge · 17 Mar 2016 at 07:10

The valve your outside tap is connected to isn't fully open on your picture.

Nazbit · 17 Mar 2016 at 09:12

FlyingFish said:
Proper diy plumbing in the pic m8

I know

Slowly working through the rooms and having them refurbished, eventually I will have the kitchen replumbed as I'd like to move the sink when we get new units.

Just need to remove that flow limitation for now.

FlyingFish said:
If your getting the desired flowrate from the kitchen tap, that is plumbed up as shown in your picture, then I would whip out the outside tap isolation tee and replace it with a 15mm compression tee and screw the flexible pipe straight into the end of it. Instead of using the nut and olive.

Then do a test to see if you can obtain the desired flow rate.

If not then look at replacing the hose for 15mm copper and possibly the outside tap.

Sounds nice and logical, thanks.

Could you just confirm which type of isolation valves have the low resistance that you mention, maybe a link or a pic.

Cheers

Nazbit · 17 Mar 2016 at 09:16

I've just noticed the daisy chain of tap connectors under the sink :rolleyes:

Would love to meet the last owner of this house, girl friend bought it before we met.

FlyingFish · 17 Mar 2016 at 16:42

Least resistance, but not 100% guaranteed to shut mains water off:
http://www.wickes.co.uk/Wickes-Brass-Fullway-Gatevalve-15mm/p/420185

Proper valve:
http://www.wickes.co.uk/Wickes-Brass-Stop-****-15mm/p/420171

And yeah those hoses look a treat

Edit: looks like the naughty word police have edited the link above..word is a male hen

Nazbit · 17 Mar 2016 at 19:15

Cheers

Pabl0 · 17 Mar 2016 at 22:28

Hedge said:
The valve your outside tap is connected to isn't fully open on your picture.

This, turn that ISO valve so the black lever is horizontal and you should have the same flow as the kitchen sink.

Nazbit · 17 Mar 2016 at 22:34

Horizontal is the off position.

It turns 90 degrees, 12 o'clock vertical position is open, 3 o'clock horizontal position is closed.

Hedge · 18 Mar 2016 at 07:34

Yes it should run in line with the pipe. On your picture it looks like it's about 45 degrees turned. Straighten it up and you might notice a change.

FlyingFish · 18 Mar 2016 at 13:31

Are people looking at a different picture to me? Although in the dark under there, it looks in line to me :confused:

Hedge · 18 Mar 2016 at 18:01

FlyingFish said:
Are people looking at a different picture to me? Although in the dark under there, it looks in line to me

When I zoom in on my phone it looks like its like /

NvidiaDan · 18 Mar 2016 at 18:12

Looks fully open to me! For easy reliable isolation on mains pressure, Lever valves are always the best option and wont restrict flow. http://www.screwfix.com/p/pegler-ball-valve-blue-15mm/11085

Is there a double check valve installed already?

FlyingFish · 18 Mar 2016 at 18:21

Hmm, if there is any doubt about whether the valve is fully open, then remove the black lever (small screw) then make sure the flats of the spindle are inline with the valve body (vertical, so flats on the left and right side)

Mick

Nazbit · 18 Mar 2016 at 18:30

Hedge said:
When I zoom in on my phone it looks like its like /

Thanks, I have double checked and it is all the way open.

NvidiaDan said:
Looks fully open to me! For easy reliable isolation on mains pressure, Lever valves are always the best option and wont restrict flow. http://www.screwfix.com/p/pegler-ball-valve-blue-15mm/11085

Is there a double check valve installed already?

Thanks That's what I've ordered, it arrived today.

There's no check valve there at the moment but I understand that it's required to prevent contaminated water flowing backwards.?

Hedge · 18 Mar 2016 at 18:38

FlyingFish said:
Hmm, if there is any doubt about whether the valve is fully open, then remove the black lever (small screw) then make sure the flats of the spindle are inline with the valve body (vertical, so flats on the left and right side)

Mick

Yes the plastic often spins but doesn't turn the body of the valve. This is also worth double checking.

NvidiaDan · 18 Mar 2016 at 18:43

Nazbit said:
There's no check valve there at the moment but I understand that it's required to prevent contaminated water flowing backwards.?

To comply with regs you do need a double check valve for backflow protection, So it's always a good idea to fit one if you are making changes to the pipework anyway.

Although you don't normally see them on most dodgy DIY installations so it's no surprise there isn't one there at the moment

FlyingFish · 18 Mar 2016 at 19:19

'Most' outside taps nowadays have this feature built in.

Edit: As well as most decent hose pipe connectors.

NickK · 18 Mar 2016 at 19:30

For outdoor I thought you needed a one way valve.. it stops the scenario where someone attaches a weedkiller spray to the outside tap and the chemicals find their way back into the house water supply.

Nazbit · 18 Mar 2016 at 19:45

Thanks for the replies

Hedge said:
Yes the plastic often spins but doesn't turn the body of the valve. This is also worth double checking.

Yes I did wonder about that, it wouldn't surprise me if when I take it off it turns out that the valve wasn't fully opening and closing.

NvidiaDan said:
To comply with regs you do need a double check valve for backflow protection, So it's always a good idea to fit one if you are making changes to the pipework anyway.

Although you don't normally see them on most dodgy DIY installations so it's no surprise there isn't one there at the moment

Yeah I'm going to replace the isolation tee for a 15mm equal tee, then a wide bore lever type isolation valve, and then a full bore double check and then I'll see what flow I get with the tap connector in place and if that's not good enough I'll remove it and go all the way in 15mm copper.

FlyingFish said:
'Most' outside taps nowadays have this feature built in.

Edit: As well as most decent hose pipe connectors.

I've had a good look at the tap, It doesn't appear to have a check valve built in, I'll take a photo of it for you tomorrow but I think I would see the bearing location on the outside?

NickK said:
For outdoor I thought you needed a one way valve.. it stops the scenario where someone attaches a weedkiller spray to the outside tap and the chemicals find their way back into the house water supply.

Yes that's what the double check valve does.

Cheers!