A little bit of everything

[Starky]

Hi all.

Firstly sorry if this is in the wrong section, but the title suggests it is a little bit of everything.

Right, I've been asked to help a good friend with a loft conversion on his fist floor two bed massioante. The work I have been asked to do is to rip out the old heat only boiler and change it for a combie. Along with the plumbing for the loft which consist of a toilet
Shower and basin. (just for info) There is also an existing bathroom which has a shower, bath, basin and toilet.

I've measured the incoming main pressure (static) at 2.1 bar and a flow rate of 12l/m. The mains coming out of the floor at the ground floor level is only 15mm. I was hoping for more as I would need to provide hot water to two bathrooms. Along with converting all the cold outlets to mains which appear to be run in 15mm copper. I can see this being a pottenial issue.

So the questions are is there a way to increase the flow rate? Which would then enable me to put in a bigger Combie. He's not up for digging a new main, so I've been looking into accumulators but don't know enough about them.

Would I also need to up the cold water pipes sizeing to the out lets? Would it make any difference? as I will now have the whole property on the mains and many different outlets competing with one another.

Thanks.

 

[Old Account]

Hi Starky,

In my opinion best option would be to upgrade the mains in coming water pipe ( if not done yet ) to mdpe 25mm that should solve the issue with more flow rate.

I guess that would be the best way of solving the issue. I just had it done few days ago. I have got another customer where I have to upgrade too.

Especially with 2 bathrooms , you definitely need to upgrade. I don't know much about the accumulators so I can't help you but perhaps @ShaunCorbs or @Chalked

Once you've got the mains upgrade it you should be fine with 15mm unless long runs

 

[ShaunCorbs]

Stuart Turner

That would be your best bet

Accumulators only keep the flow when more than one outlet is open at the same time they don't really increase the flow that much

Best if you can repipe from the mains stop tap (new) in 22mm and don't reduce it until your close to the outlets

Another thing that helps is full flow ISO / lever valves, don't install the cheap ISOs as they restrict the flow even more

 

[Starky]

Thank you both for your replies.

Funnily enough I've been in contact with Stuart turner today, they subsequently put me on to there sister company TWS. I spoke with a nice chap called Martin who took down all the relevant information to give me a quote.

He advised that an accumulator would give me the 17l/m I need for a big combie. But also stated that to increase pressure I could retro fit a pump on to help.

Any other thoughts or opinions welcome.

 

[ShaunCorbs]

Check my link would get around 20lpm with my link

Or tws mains boost plus

Tws are very good and Martin will sort you out

You won't boost your flow past 20lpm as the waterboard don't like you if you do

 

[Starky]

Hi shauncorbs.

I was under the impression that the accumulator would help the flow rate to any given outlet and only needing one open.

I'm not very clued up on these units. The one you suggested looks good as it appears to be able to fit into a cupboard. I will only need 17l/m for the combie required.

If you have the time could you elaborate on how the accumulator works?

By my little understanding the accumulator stores water at let's say 2bar, then delivers the water to your out let's. My sticking point is how does it increase the flow rate just by simply storing the water? Or does it increase the dynamic pressure?

With the unit that also has a pump it will increase the stored pressure to lets say 3bar and in turn if the pipe sizing is correct will increase the flow rate. Does this sound right?

Thnaks.

 

[ShaunCorbs]

It won't help that much if you open one outlet but if you open two they won't drop to 5lpm would stay around 10lpm / full dynamic pressure and flow

It's exactly like an expansion vessel normally pre charged about .5-1 bar higher than your incoming main

It's a stored vessel of 100-500l (depending on model / needs ) and forces that water out think of a super soaker ish

And it's stabilises your dynamic pressure when multiable outlets are open

The pump one will boost your incoming water pressure and flow to 3 bar and 20lpm

Sizing of the accumulator is crucial if your using it for both hot and cold half the capacity of the unit so a 100l one could supply 50l cold 50 hot

With two outlets this will drop to 25l each

As a rough estimate

So Better to have more than you need than not enough

 

[Starky]

It's nice for people to share their own experiences and pass on knowledge, so thank you for the insightful exsplanation.

I will wait for a reply from Martin at TWS before I go any further.

Why also do you say water company's don't like you to have more than 20lpm? I'm just curious as I've seen other threads with people suggesting they have inexess of 30lpm.

 

[ShaunCorbs]

It's nice for people to share their own experiences and pass on knowledge, so thank you for the insightful exsplanation.

I will wait for a reply from Martin at TWS before I go any further.

Why also do you say water company's don't like you to have more than 20lpm? I'm just curious as I've seen other threads with people suggesting they have inexess of 30lpm.

When you start sucking more than 20lpm you could rob someone else's supply / more demand than the system can supply

 

[Starky]

Lol. Makes sense

Thanks again Shaun.