need advice about a power shower, cw tank, hw tank and pump

[liam2523]

i have a 25 gallon cold water storage tank in the loft and a 27 gallon hot water cylinder on the same floor as the bathroom. the cw tank is about 3 foot above the shower head. i want to fit a 9 litres per min shower pump and have been told i should have at least 50 gallons cw in the loft and therefore i could join another 25 gallon cw to the one already in place. if i was to do this would i need to get a bigger hot water cylinder aswell? if so how big? if i dont need a bigger one could someone also tell me why please?

both hot and cold taps run really fast in bathroom on the bath and basin. do i actually need a pump?

thanks, liam.

 

[hi-spec plumbing heating]

you don't need a new cylinder

larger tank is a regulation if your supplying cylinder + shower.

pump is needed because gravity or 0.2bar will give your a poor shower.

you say your taps are good pressure. try having one at head height standing in the bath then you'll change your mind.

 

[Rob]

25 gallons = 110 ltrs 110 / 9 = 12

So you'll get a 12 minute shower with what you've got before you run out.

Yes you can increase capacity by having tanks parallel.

Cold is more important as its feeding both shower and hw cylinder and you wont be drawing 9 lt/m of just HW.

Showers usually have dedicated supply from tanks so taps stay off gravity.

 

[Durgo]

You could get a big pump and a bigger/additional cold tank and you could get a bigger cyclinder but you may then need a bigger boiler - otherwise your thermostatic shower valve will be holding most of that flow back after 5 minutes of showering...

If this was the case youd be better off changing the boiler meaning you wouldn't need any of the tanks or pumps (if you got a combi)