Accumulator or Replacement supply pipe?

[plumbamateur]

I have an issue with my water supply. I have a combi boiler (no stored hot or cold water) and if a tap is opened (or toilet flushed etc) whilst showering then the shower slows to a trickle. This is extremely frustrating The problem is exacerbated by having a loft conversion with an additional bathroom, but having 2 showers running simultaneously is impossible.

I have an old lead supply pipe to the property, which I suspect is the issue. I'm getting about 9l/min flow rate to the kitchen tap, with no other outlets open. I'm afraid I don't know what the water pressure is (presumably i need some equipment to measure this?).

Should I opt to replace the lead supply pipe with 25mm MDPE, or should I look to install an accumulator? I have space enough in the loft for this, and was considering a 500l model to give plenty of capacity. ROUGHLY speaking the cost looks similar - about £800 for an accumulator tank, and I've been quoted about the same by a contractor to use a mole to lay a new supply pipe.

I suspect that i should concentrate on the supply pipe, but i'm wondering if i'd get better performance using an accumulator?

Thanks in advance

 

[dcawkwell]

Since you have lead pipe.
I'd be looking at replacing the main.
I think the water companies cover some of the costs when replacing
lead piping.

If you are in London though you might find you've gone through all
that and still have crap flow due to low pressure. Well you will live in London you can't expect proper water supply there.

 

[plumbamateur]

Thanks for your reply, I guessed that would probably be the first thing to do. Once the main enters the house, all the pipework is 15mm copper, including up to the loft. Does that matter? I guess my question is: upgrading the main supply pipe into the house should in theory have the effect of allowing more litres/minute to enter the property and so enable 2 showers to work simultaneously - but is this effect negated by having 15mm copper to the actual outlets?

Thanks.

PS your comments re London - agreed, water pressure seems to be a problem everywhere here - i know of lots of others who have similar issues. V annoying. Unfortunately I can't choose where to live based on local water pressure

 

[dcawkwell]

Thanks for your reply, I guessed that would probably be the first thing to do. Once the main enters the house, all the pipework is 15mm copper, including up to the loft. Does that matter? I guess my question is: upgrading the main supply pipe into the house should in theory have the effect of allowing more litres/minute to enter the property and so enable 2 showers to work simultaneously - but is this effect negated by having 15mm copper to the actual outlets?

Thanks.

PS your comments re London - agreed, water pressure seems to be a problem everywhere here - i know of lots of others who have similar issues. V annoying. Unfortunately I can't choose where to live based on local water pressure

If you only have 15mm in the house that shouldn't be a problem.
You should still be able to get 20-30 litres a minute through
a 15mm pipe providing there is pressure behind it.
I advise you measure the static pressure you have and also
the pressure with a small flow of water.
If it is very poor say 1 to 1.5 bar. No point in upgrading the main
the problem is the poor pressure.
Only answer to that is a whole house pump set.

Moving to somewhere more civilised is another option.
A shame our government is more concerned with broadband speed
rather than ensuring houses and the country have proper water supplies.

 

[plumbamateur]

Thanks again. I've ordered this little chap to take the measurement:

http://www.amazon.co.uk/gp/aw/d/B0001P0F5O/ref=mp_s_a_1?qid=1331812241&sr=8-1

Assuming my pressure is low, would this be a suitable contender to pump water into the house?

http://www.plumbnation.co.uk/site/grundfos-upa-15-90-home-booster-pump/

Kind regards

 

[dcawkwell]

Thanks again. I've ordered this little chap to take the measurement:

http://www.amazon.co.uk/gp/aw/d/B0001P0F5O/ref=mp_s_a_1?qid=1331812241&sr=8-1

Assuming my pressure is low, would this be a suitable contender to pump water into the house?

http://www.plumbnation.co.uk/site/grundfos-upa-15-90-home-booster-pump/

Kind regards

You can't directly attach a pump to the cold main.
You need a pump set that contains a break tank and pump.
But measure the pressure first.

 

[mysteryman]

It is best to get the main sorted out first, and then add kit as already described if there is still inadequate flow. Make sure you fit suitable showers for combis, with a sensible flowrate.

 

[plumbamateur]

Hi guys, the pressure gauge arrived so I tested the pressure at the garden tap. It's 2.6 bar ... This is with all taps in the house off. I guess the question now is should I go ahead with a replacement 25mm supply pipe, or isn't it going to make much difference?

is there a formula for estimating flow rate at a given pressure and pipe width?

What do people think about the accumulator idea with 2.6 bar, and is the general view still to tackle the main first?

Cheers David

 

[dcawkwell]

Hi guys, the pressure gauge arrived so I tested the pressure at the garden tap. It's 2.6 bar ... This is with all taps in the house off. I guess the question now is should I go ahead with a replacement 25mm supply pipe, or isn't it going to make much difference?

is there a formula for estimating flow rate at a given pressure and pipe width?

What do people think about the accumulator idea with 2.6 bar, and is the general view still to tackle the main first?

Cheers David

2.6 bar static is reasonable. I get about that static and I have good main
pipe to my house (I know I replaced it due to a leak) however because I am in rural area it still drops off very rapidly to just 1 or so bar as soon as I open a hot tap fully.

You'll be able to get the actual flow you can expect as soon as you connect to the stop valve in the street.

 

[sherbert]

use this

http://www.twsuk.com/?id=25

Trust me with a 500litre accumalator you will never have a problem

 

[Kev F]

Im in Cambridgeshire and Anglian were replacing lead for free so definitely worth checking with local water board

 

[plumbamateur]

Eaton - already checked with Thames Water and unfortunately the most they'd stretch to is a couple of hundred quid contribution to a replacement *if* I had a leak (which I don't).

dcawkwell - Thanks for your help so far, I really appreciate it. I'm going to get the supply pipe done. It'll be good to get rid of the lead in any case...

Anyone know of a decent external contractor who'd do a moling job in E11?

cheers all

 

[Kev F]

Oh what about that leak that you've just found

 

[plumbamateur]

Oh what about that leak that you've just found

LOL!

"...yes, and there was water EVERYWHERE! I've had it replaced as an emergency... "!