15mm rising main to 4 apartments?

[dan_the_plumber]

Hi
I’m currently working on a 3 story house that’s being converted into 4 flats. I installing 40kw boiler, 15 rads, 4 Heating zones plus a hot water zone. Etc etc
Each flat has a kitchen sink, toilet, basin and electric shower.
Problem is, I’ve got a 15mm rising main. ‭Im hoping it’ll just be adequate.
However as back up I’ve thought about installing a booster set.
As a back up to the back up I’ve thought about installing a break cistern then a booster set.
I wondered if you had some experience and thoughts on this?
I’m sort of dreading telling the client that he needs a 25mm rising main, especially when the main also supplies 2-3 buildings. Thanks...Dan

 

[DevsAd]

Hi. That is incredibly helpful if you, Thanks!

Actually since posting on here I have been in touch with Stuart Turner and have completed a site survey taking static and working pressures etc.

I will speak to them Monday and they should be able to recommend a suitable product. I’m hoping I can just go for a mains boost accumulator without a pump.

Once I know what to go for the I can look at price and will compare with the Challis products.

Your points about stored potable water are very interesting. In fact I hadn’t quite got to thinking about that, but now will definitely take that into account.

Thanks again for your help

There is a large difference between pumped and non-pumped accumulators. The latter relies wholly on the existing water pressure for its delivery performance, and if you reckon that will be only be at around 1.5+ bar at the top flat, then I don't think it's going to be successful. Also, lower flats will affect the performance of the higher ones if they are all drawing simultaneously. Unpumped accumulators are ideal for when the mains pressure is good - 3+ bar - but the incoming flow rate is low.

The pumped models aren't that much more costly, and there is no 'pump effect' to the way they work as far as the flats are concerned; the pump only fires up when it needs to to recharge the accumulator. The pressurised accumulator itself does all the water supplying to the properties, and this can be at a very impressive flow rate and driven by a guaranteed pressure.

It will be interesting to see what ST come up with. I'd thoroughly recommend contacting Challis and Grundfos too - there are some differences.

 

[AWheating]

New 50mm main, 22mm balanced hot and colds to each flat with secondary return.

 

[AWheating]

That's assuming shared billing.

 

[king of pipes]

In an ideal world bud but the op has said not much chance of a new main upgrade . kop