Ball a stop isolation valve - easy to swap?

[dishman]

I have ball stop (restricted bore) isolation valves on every outlet in the property.

I wish to swap these with a full bore equivalent.

Assuming these are compression fittings, will it be an easy swap as I am imagining it to be?

1. Turn off the supply to the taps.
2. Open the taps to drain them as much as possible.
3. Towel ready round the pipe for water in the short run of pipe.
4. Unscrew the nuts for the isolation valve and remove
5. Replace with full bore variety.
6. Turn everything back on and check for leaks.

Anything I am missing?

I am doing this because it is suggested that these can contribute to poor flow due to the very small bore in a low pressure system. However, when I asked the plumber about swapping them out he did not think it would be worth it (especially if he did it and charged for it) and I would see little difference in flow.

I don't mind trying it myself if it is an easy switch with a compression fitting.

Is there any way one can easily identify if the existing valves are compression types?

 

[Madrab]

If you have a tank fed, LP gravity system then full bore ISO valves can sometimes help with increasing flow, yes. Will it make a huge difference, doubtful.

Compression fit ISO valves have a nut either end

Oh and they're ball-o-fix BTW

 

[dishman]

Super - I thought I had got the name wrong....but just went with it.....

Ahh, the existing ones have nuts....so they should be compression fix.

So a swap should be a pretty simple diy job......correct?

Am I correct that either this

http://www.screwfix.com/p/full-bore-isolating-valve-15mm/46860

or this

http://www.screwfix.com/p/full-bore-lever-ball-valve-15mm/80413

is the correct replacement. I assume if they say full bore, there is no bore restriction.

Many thanks in advance...

 

[Burnerman]

Obviously the full bore fittings will be somewhat longer than your existing isolators, which may or may not be an issue in your installation.
The nut threads are the same of course but some sealant paste around the olives should guarantee a drip free job first time.
John

 

[Agile]

Many doubt you will get a significant increase in flow rate.

So I suggest that you measure the flow rate from the worst one in litres per minute and then change just that one and see what difference it makes.

Tony

 

[dishman]

Update:

OK......as an initial test to see if it is worth it......I tested it on a downstairs basin which had the correct low pressure taps. The upstairs taps are high pressure taps (incorrect type) so there is no point testing on those as I think the taps are the bigger issue.

So....using a flow jug thing.....

With restricted bore it seemed to top out at the 10.5 litres per min (maybe 11 if we are kind).

Fitted a full bore and it seem to top out at 12.5 litres per min (touching 13 just about).

So, the result is a 2 litres per min increase or thereabouts......

Thoughts on that? Worth the bother?

Removing the old valve was a bit more difficult than I thought......specifically removing the old olives as they seem to have created a ring finger type compression in the pipe work so are pretty hard to remove.

Ideally I should have cut the pipe a bit, I think fitting the slightly larger valve pushed some of the pipe work down, which I assume can put a pit of pressure on joints. But it was not a huge amount of force.

I ended up reusing one olive. No leaks are apparent.......yet. But not the neatest job as it was only a quick experiment. I did use some plumbers paste (potable water type).

 

[Agile]

My first observation is that a washbasin only needs 4-6 li/min.

What do you want such a high flow rate for?

Even at a bath tap 10 li/min is enough.

Be aware that half the country has a standard combi boiler which only gives a maximum of 9 li/min!

Tony

 

[dishman]

This......is a good point.....it was more of a test to satisfy my own curiosity. The downstairs basin was just the easiest one to test on, it did not require it per say.

The bath upstairs is the bigger problem as this struggles to get past 4l/min but this is more to do with the tap issue I think, those will be replaced soon. It just so happens that every outlet has a restricted bore isolation valve, hence the consideration of swapping these out to help.

Maybe I am a bit spoilt, the house that I lived in most of my life had a open vent system with tanks in the loft. The hot water on most outlets is 18l/min (no pump) and the mains fed cold was at 22l/min. I rarely have to open the tap fully on the basin but it is fantastic for a bath.

No other properties I have been in have ever matched this.....I have always been appalled by combi flow rates.

I was considering putting a mixer shower on the bath if I could get the flow high enough but I do not think the pressure in this house is good enough. Maybe 0.1 bar at most. A shower pump may be the way forward.

 

[Agile]

A mixer shower is for the convenience of using a shower.

I get quite clean with my 6 li/min electric shower!

Tony

 

[dishman]

Ahh therein lies my problem, the bathroom has an electric shower, but it is appalling. It gets a flow of 2.5 - 3 litres per min on the lowest hot setting. It is little more than a dribble. It also has a restricted isolation valve on the inlet.

Hence, I am investigating the likely flow I could expect from a mixer tap shower. Which led me on to looking at ways to improve the flow as much as possible.

 

[HERTS P&D]

Tony are you telling us that with all of your gas knowledge, you have an electric shower?

Andy

 

[Agile]

Don't fall into the trap of comparing a shower with an open tap flow rate.

Typically a shower needs about 0.5 bar pressure remaining on the pipework to give a good exit speed.

To get that you need at least 5 m head of water to the top of the loft tank. Even ignoring pipework flow resistance.

Tony

 

[dishman]

So I assume the only way to ensure I have enough pressure for the shower (mixer tap) is to add a pump. As I do not have 5m head of water.

Or, work out why the electric shower flow is so poor.

I would prefer to rid myself of the electric shower as it makes the tank of ready to use hot water pointless. I am just paying to heat water an an expensive rate when hot water is available in the tank.

 

[Agile]

Tony are you telling us that with all of your gas knowledge, you have an electric shower?

Andy

Its really because the bathroom renovation is as yet unfinished!

But with solar panels an electric shower is an symbiotic choice.

I also have an unvented cylinder with a solar thermal coil and an immersion which I will probably use from the PV system when the bathroom is ready.

Don't have much liking for fancy cars or showers.

Tony

 

[Burnerman]

Mr. D, have you considered a power shower?
So long as you have an equal head of cold and hot water, they work rather well. Looking like an electric shower on the wall, they have an internal pump that boosts the flow.
Just a thought, but with 0.1 bar pressure you need something else!
John