New CH & DHW system - advice please

[trevt]

Hi

Looking for some advice on the type of CH system I should have installed - combi, sealed or vented. I'm really dithering between combi and sealed.

This will be a fresh install from scratch in a property being renovated - so floors are out, ceilings are out, giving chance to run anything without the usual hassle.

Property is a dormer bungalow, detached and about 550 - 600 m2 usuable floor space. There is very limited storage especially upstairs for storage tanks.

For that reason alone a combi would seem best. But we will have two ensuites and a bathroom requiring high-flow shower (pumped shower performance?) and very hot. It's likely (within system lifetime) that 3 showers will be running at the same time.

For those reasons a sealed system with 200l (??) tank seems wise. We have space downstairs to build an "airing cupboard" but both ensuites are upstairs.

Another alternative might be combi with storage?

Mains flow rate is strong and should feed a combi no problem.

Any useful advice & comments more than welcome.

Thanks

 

[Dan Robinson]

No combi will run two outlets properly at once.

A storage combi might.

An unvented will if there is enough mains pressure AND flow.

Will 3 showers REALLY be run at once?

Any useful advice & comments more than welcome.

You get what you're given here - it's free advice, so everything should be welcomed. Rough with the smooth and all that .

 

[trevt]

Dan - thanks.

I welcome all comments, just more so the useful ones

As to 3 showers it's possible in the mornings though 2 is more likely at any point in time. Suspect it'll be a case of they're there so we'll use 'em in the mad morning rush.

You seem to suggest a vented system - that needs a header tank which I really will struggle to fit anywhere but downstairs (never mind a cold water tank or HW cylinder). A sealed/pressured system seems to do away with the header tank and let me pump at least one shower?

 

[Dan Robinson]

No, I am suggesting proper measurement of the admins supply, possibly upgrading it, and fitting an unvented cylinder.

Also consider an accumulator to boost flow (not pressure).

 

[trevt]

Dan

Thanks, re-read your first post and, really I should read things when awake

Thanks for the advice

 

[Dan Robinson]

Good luck with it.

 

[dcawkwell]

System boiler and unvented cylinder.
Assuming these is good flow and pressure on the incoming mains.