Hot Water Supply?

[ballofix]

I have a customer who is renovating a property. His main concern is that he will be able to run 3nos Raindance showers at the same time for 10mins, which equates to approx. 75 litres per min.
I am looking into accumulators, break tanks and pumps to boost the cold water supply, but im unsure what would be the best way to supply the hot water which would be 50/55ltr/min for 10 mins
The boiler for heating the water would be decided once I know what will be distributing it, the underfloor heating requires 37kw, so I can either put one larger boiler in for both, or two, one for the heating and one for the hot water.
Anybody done anything along these lines. I don't mind overspecing it a little but I do not want to underspec it.
Thanks in advance.

 

[Ermintrude]

Buy two cdi classics. External pumps on to the WB LLH. Run blended weather comps to the ch and blended to ufh. Smash the ACV SL 320 or 420. But the 420 will be under heated with only 80kw it will demolish 90kw!

ACV will wee all over any tank.

 

[ballofix]

Thanks Ermintrude. I was looking at Tws tank in tank. WB LLH apparently are only good for 70 kw
Not sure what you mean about blended weather compensators? there is only ufh no rads

 

[Ermintrude]

Think they do a bigger one? If not buy one off the shelf. If your a clever bunny u can use your ACV SLME as a LLH.

 

[Ermintrude]

Oh if it's jut ufh can u just set up as normal. Weather comp on ufh is a little bit too far. Just set up boilers for cylinder demand as that will outstrip ufh 10:1. 37kw of ufh? That's a lot? Over 600m2 at 75w/m2? Surely your house is better insulated than that? Defo need LLH and I would set up boilers on a slave basis. Or set one with a s/l for uff zone each and both for the DHW. Or perhaps use pipe stats to switch them in. Both boilers at low chugg will be inefficient.

Look at two ideal vogue 30 system boilers to a LLH. Thats 60kw which should keep your cylinder rocking. And you gas meter alive. You can bring back smart measure to boiler aswell.

 

[AWheating]

so your water main runs at 55lpm?

 

[ballofix]

so your water main runs at 55lpm?

No mate that is going to be supplied by a break tank and twin booster pumps :- )

 

[ballofix]

HI Ermintrude. Thanks for the as always very informative reply. Why mate would you not have say 2 nos 35 kw boilers firing the ACV as apposed to 2 nos 30 kw.
Not questioning the wisdom only wanting to learn why :- )

 

[PhoenixServices]

His post mentioned break tanks and pumps etc for the main.

 

[Ch4 plumbing]

37kw for under floor heating demand....airport by any chance?