Instant hot water - HELP NEEDED!

[BIGNICK]

Hiya guys and girls..
just a quick intro, my names Nick I've been a domestic plumber for around 6/7yrs, mainly bathroom installation and plumbing maintenance for letting agencies and domestic clients..

ive be joined up because I've had a promising opportunity from an experienced property developer, wanting to developer one of his offices in to two flats in Kew, London.

here's the plan. IT WONT LET ME POST PICS.

the property is in a block of offices, the dotted area in the first pic will be raised to accommodate services.
Theres no gas, the buildings can't be altered at all, weather that means completely or it's all right to pull a pressure release discharge through, I'm not sure, assume we can't.
it also has to pull the minimum kW possible, my client wanted the smaller flat to draw no more than 4kw and the larger 6kw. I did inform him his kettle at home used 3kw..

In my eagerness to please I said it wouldn't be an issue, but in the cold light of morn it seems slightly trickier to achieve.

Any suggestions, advice, experience, vodka or rum would be greatly appreciated..

thanks in advance.

Nick

 

[Dotty]

Assuming that there's no bath, just a kitchen sink, wash hand basin and shower in each flat I'd go for a redring EW15 and EW10 respectively, unless the kitchen and bathroom are close by in which case a single 15 would do.

These have the pressure relief on the mains fill so you can safely pipe into the waste via tundish and trap.

http://www.redring.co.uk/ew.html

 

[BIGNICK]

Thanks for the reply..

I can't quote, post links or attach URL's for the pictures, so it's a bit hard to explain.

There's is a bath! Lol..

what ive discussed with the client now, is to kit out the showers with electric mains fed showers. In the smaller flat I'm going to fit a local heater, like a redring or similar..

in the larger flat the kitchen will have a local water heater, Redring etc, showers to be electric. But that still leaves the bath and two basins?
theres going to be a roof/loft space above the ensuite, any thoughts?

is there a local water heater man enough to fill the bath? Or would it be logical to fit a small pressurised cylinder in the ceiling cavity?

 

[BIGNICK]

Thanks for the reply.

The larger flat does have a bath.
im struggling because I can't upload pic/links to pics or quotes..

the larger flat has an ensuite and with basin and shower and a b/room with bath and basin.

What I think to be the best solution is to install electric, mains fed showers, taking them out of the equation. Fit a smaller water heater (ew10/15) to supply the kitchen sink and b/room basin in the smaller flat.
which just leaves the bath, two basins and the kitchen sink in the larger flat?

is there a heater man enough to supply all the above, or should I localise the kitchen with its own heater?
there also a ceiling cavity with around a 1200mm clearance so would pressurised cylinder be an option?

thanks again

 

[SimonG]

Direct unvented on a 3kw immersion. Possibly discharge pipework into internal soil stack?