Small Plumbing Job

[Steve Lowe]

Hi,

I've a small plumbing job to do over the weekend - fitting an outside tap.

I intend to T off the 15mm cold supply that comes from the main stop tap in the house under the kitchen sink and then feeds the cold water tank in the loft, my T is about 3 foot along this pipe from the main stop tap.

I was thinking of putting a service valve in between where I put the T and where the pipe goes up the boxing in the corner of the kitchen, about 12 inches from this T

This would mean that in future if I want to work on the cold water from this T back to the main stop tap I could just turn the new service valve and not have to drain the cold tank in the loft.

I've got to run a cold supply into the utility for the Washing machine at some future point.

IE

STOP TAP | T | VALVE | TANK

Does this make sense ?

Now coming to my quandary, do I put this new valve in with the flow arrow going with the flow or, since I really want it to stop the flow coming back down the pipe do I install it the other way round.

Thanks for any guidance

Steve L.

- Steve Lowe

- E-Mail : [e-mail]

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- UK Resident although my e-mail address is usa.net

[Dave Plowman]

It goes in the direction of the normal flow. When shut off, it will work equally well in either direction.

You might consider siting it so that the kitchen tap still works with the rest of the house turned off.

[Roger Mills]

I don't understand your problem! Presumably the feed is into the *top* of your cold storage tank via a ball valve? So if you do break into the cold feed above the main stop-tap (as you will have to to insert your tee) the cold water tank won't suddenly empty itself! [You may spill a pipeful but

*not* a tankful].

Having said that, it's a good idea to have an isolating valve close to each tap or cistern - so that you can easily change tap washers without having to turn off the whole house supply.

Roger

[BigWallop]

Have a look through this:

[Steve Lowe]

Thanks for all the replies,

Whilst I'd forgotten that the pipe only goes to the cold tank above the water level , putting the valve where I'd suggested will stop any water in the pipe from putting in a appearance when I do future plumbing.

The outside tap has a in built one way valve to comply with the water bye laws.

Thanks for confirming that it doesn't really matter which way the valve goes.

Regards and thanks for the pointers.

Steve L.

- Steve Lowe

- E-Mail : [e-mail]

- Before Replying Remove .NO.SPAM

- UK Resident although my e-mail address is usa.net

[BillP]

Hi Steve,

Water taps with inbuilt check valves should only be used on existing outside tap installations, to replace an existing tap that has no check valve or to replace an existing defective tap. On new installations, water regs require that a separate double check valve be installed inside the thermal envelope of the house. The service valve should be fitted in the line to the tap so that it only isolates the tap. The if the pipe is going through a cavity wall, it should pass through a pipe sleeve sealed at both ends.

The ideal installation is.

1. Tee into the mains pressure cold water at a convenient point.

1. Fit service valve, prefererebly full bore lever operated. Any time you want to, you can just turn it with the lever, you haven't got go and find a screw driver, handy if its an emergency.

2. Fit double check valve.

1. Put a sleeve of 22mm copper or 19mm overflow pipe through the wall.

2. Take the 15mm through the sleeve to the outside.

1. Fit the outside tap (with no check valve)

2. Seal both ends of sleeve.

Bill

[BillP]

Hi Steve,

Regarding service valves with arrows.

If you install a service valve the wrong way round, you will not notice any difference. It does not effect the flow. It may work perfectly well for the whole of its working life. However... If you look down each end of the service valve, you will see that the ball mechanism has been pressed in from one end. The reason for the arrow is so that it gets installed in such a way that when it is turned off, the pressure of the water holding it is holding back has a tendency to push the ball into the seating. If a valve was part of a duff batch, and was installed the wrong way round, the water pressure would have a tendency to pop the ball away from its seating and it wouldn't be a service valve any more :-)

Bill