Insufficient hot water for new bath

Plumbing covering hot and cold domestic systems, drainage and related topics

Insufficient hot water for new bath

Postby Graeme » Thu Nov 01, 2012 10:20 pm

I've just fitted a walk-in bath for my elderly mum. Unfortunately we don't seem to have nearly enough hot water to fill it (These things hold about 230 litres and need to be fairly full because the occupant sits on a moulded in seat)Our HW cylinder is obviously too small but the cold water tank that feeds it is also too small because first the HW turns cold then it stops altogether! Mains water pressure is relatively low (about 3 bar tops)

I'm tossing up between fitting a massive cold water tank and huge cylinder or just a big unvented cylinder. Space is a problem so last option would be preferable - BUT - would a large unvented cylinder be any good, bearing in mind the low mains pressure? It would also have to be far from the bath with lots of bends + a thermostatic mixer (anti scald because you have to be in the bath before filling!)- so pressure drop might make the flow speed so slow it would take about half an hour to fill the bath!

Any bright ideas anyone?

Graeme
Graeme
 
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Re: Insufficient hot water for new bath

Postby keith » Sat Nov 03, 2012 2:59 pm

Another option would be a combi boiler but if you have low mains pressure it would still be a slow bath fill. You could either fit a larger capacity cold tank or depending on the space available fit another tank beside the existing, either way you will need a larger h/w cylinder. Once you have enough cold storage you could fit a pump to get greater flow/pressure.
keith
 
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Re: Insufficient hot water for new bath

Postby Graeme » Sun Nov 04, 2012 1:49 pm

Thanks for that Keith. I'm coming round to the idea that a straightforward swap of cold and hot tanks is the answer (ie keeping the vented system) Your idea of pumping a tank sounds good.

Do you know if it would be feasible to add a second cylinder working alongside the existing one - rather than replacing the existing one with a bigger one? The trouble there is I'd need two coils and two vents back to the (same?) header tank. Not sure!

Graeme
Graeme
 
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Joined: Tue Aug 28, 2007 10:43 am


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