Miniature Valve/Gate Valve

[silverhornet]

To all plumbers out there

I have just had a new boiler fitted and as I was waiting for the plasterer to turn up I had the plumber plumb everything in so that there was nothing feeding the kitchen as I was going to undertake this at a later date. The walls have now been plastered and I'm about to set the pipes up for the sink, dishwasher and washing machine.

As I only really need the cold pipe at the moment as I have no sink (and all appliances are cold feed only) I want to get all of the cold pipes on the wall and then work on the hot when I get the time.

In order to make my life a bit easier as I'm undertaking the work as and when I get the chance I want to fit some service valves from the boiler and cold water end (the mains feeds the boiler first and then goes off and does the bathroom and kitchen).

My question is:

Are there any rules of the trade which suggests when different types of valves are fitted as I was going to fit minature service valves from the hot water out of the boiler and then from the T piece which splits the feed to the bathroom and kitchen - so 3 vavles, one at each side of the T so I can decide how to stop the flow on this on going project i.e. all flow or just kitchen/bathroom.

Now to some this might be OTT, but that's what I want to do (unless the advice is it's a big no no) although my concern is over the flow through the valves as the miniature valves have a smaller bore than gate valves. Or will this not make a noticable difference to the pressure in a first flat maisonette with the valves approx 1m from the combi boiler? I am also planning on taking this approach with the cold water.

Regards

Ian

 

[Bahco]

Use full bore isolating valves to be sure. Cost more but you will not have to redo again if other valves are too restrictive.

Your choice

 

[JohnD]

It is true that these little service valves, although very neat and useful, do restrict the water flow because the hole inside is very small.
However, they are made in different sizes, so if you fit a 22mm service valve on a 15mm pipe, using a reducing set, then the hole will be reasonably big and should not prevent you getting a proper flow.

When used e.g. on a basin tap or a WC cistern, the obstruction is not usually a problem, so 15mm ones are OK.

The same applies to flexible braided tap connectors, which are also very useful but have a narrower bore than the pipe size they fit.

Gate valves do not obstruct the flow when open, but they are not totally watertight when closed, and are big so can be rather unsightly if left on show.

 

[silverhornet]

Many thanks for the advice

Ian

 

[Softus]

I would use 15mm full bore lever valves, i.e. like this:

BTW, I can't see any advantage in having the third valve (the one before the tee), and this would just adding two extra joints and one point of restriction.

 

[JohnD]

... like this: ...

can't see it.

Edited: i can now.

 

[Softus]

Open eyes?

 

[silverhornet]

Ah, thanks Softus.

Can't see the point of the valve before the T myself now

Will track them down tomorrow

 

[Softus]

Will track them down tomorrow

Tuesday would be easier - any plumbers' merchant will have them.