Worth having communication pipe upgraded?

Hessles · 5 Mar 2014

Hi all,

Any advice would be greatly appreciated!

Bit of background: House has an unknown size feed pipe but at the house stopcock end it is 20mm MDPE as a water meter has been fitted. The water main is 100mm Ductile Iron which runs in the footpath outside the house. There is a boundary box with a stop tap in which I estimate is 1m from the main (footpath is 2m wide)

I'm going to overlay the service pipe in 32mm MDPE as I'd like to install an unvented cylinder and wondered if the (1m) communication pipe would pose much of a flow restriction and be worth paying to be changed?

House no. 27

Craig

Agile · 5 Mar 2014

Without knowing what size it is its impossible to say.

An unvented cylinder really needs a MINIMUM of a dynamic flow of 22 litres per minute @ 1.0 bar

Measure what you have at the moment and then remeasure when you have upgraded to the 32 mm pipe. Only then can you judge if its necessary to upgrade the communication pipe.

That can be quite expensive too. Often about £500 or more!

Tony

Hessles · 5 Mar 2014

Agile said:
Without knowing what size it is its impossible to say.

An unvented cylinder really needs a MINIMUM of a dynamic flow of 22 litres per minute @ 1.0 bar

Measure what you have at the moment and then remeasure when you have upgraded to the 32 mm pipe. Only then can you judge if its necessary to upgrade the communication pipe.

That can be quite expensive too. Often about £500 or more!

Tony

How is the dynamic flow calculated?

I have a pressure guage available if that will help at all?

Agile · 5 Mar 2014

Its not calculated, its measured!

Put your pressure gauge on a cold outlet, garden tap or washing machine perhaps.

Take cold water from taps until the pressure reduces to 1.0 bar and the measure each flow rate individually with ALL of them running and add them together.

Tony

Hessles · 5 Mar 2014

Thanks very much for that! Much appreciated

Hessles · 5 Mar 2014

Would it be beneficial doing it at a particular time of day?

Agile · 5 Mar 2014

The worst case is usually when people have finished work and bathing and cooking and often 5.30 to 7.30 in the evening.

That does vary a little according to the social class of the neighbourhood and typical working hours for the kind of jobs they do.

Tipper · 5 Mar 2014

Agile said:
The worst case is usually when people have finished work and bathing and cooking and often 5.30 to 7.30 in the evening.

That does vary a little according to the social class of the neighbourhood and typical working hours for the kind of jobs they do.

Or in my case whether the farmer at the end of the lane is washing his cows' udders!

Pressure varies from 4 to 6 bar.

Agile · 5 Mar 2014

In your case you can fit a 3 bar reducing valve and still have more pressure than 90% of London!

Hessles · 8 Mar 2014

Tony,

I've measured the existing flow using the above method. I got 32 litres per minute out of 2 taps at 1.5 bar. I couldn't get it down to 1 bar without using the garden tap, I'll do this tomorrow when I get a hose union to direct the flow down the drain via some hose.

Is this sufficient for an unvented cylinder?

Mains feed is in the garage which is going to be knocked down and rebuilt as we're extending above it so upgrading and moving it won't be hard work.

New feed, boiler and cylinder can all go in the new utility to maximise flow for 2 bathrooms.

Agile · 9 Mar 2014

That is more than enough!

But measure it again at 1.0 bar as thats a better benchmark pressure for reference purposes.

Tony

Hessles · 9 Mar 2014

Agile said:
That is more than enough!

But measure it again at 1.0 bar as thats a better benchmark pressure for reference purposes.

Tony

Thanks for your help Tony, in your experience would I gain anything from overlaying the main feed without doing the communication pipe? (It wouldn't be much effort) The run would be about 15 metres

Agile · 9 Mar 2014

Based solely on your figures I would say that you don't really need to do anything at all.

But if its easy for you then upgrade to 32mm as that will do no harm and gives the best possible results.

Tony

Hessles · 9 Mar 2015

Thanks for all your help before!

We're finally at the stage of overlaying the main feed in 32mm MDPE.

I've contacted Secern Trent about upgrading the meter size and there's 2 options 22mm and 30mm which threw me!

Does a 30mm meter take 28mm pipe? I've got to get the pipe work ready for the upgrade prior to their visit.

Craig

Agile · 9 Mar 2015

You will need to ask them.

But its likely to be a blue poly size so probably for 32mm.

But beware of the charges.

In many cases they charge an extra standing charge for larger pipe sizes.

Tony

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Worth having communication pipe upgraded?

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