Please help with power shower (mains fed vs pumped cold)

[SimonD]

Hi all,

I'm trying to work out what to do with the new shower I'm ordering. I've a standard gravity fed system and we're fitting a pump to it.

We've got a 150 litre hot water cylinder and a 'not very big' (I'll measure it up tonight) cold tank in the loft. I've got two options with the pump:

1) Fit a standard 2-3 bar positive head twin pump and take direct 22mm feeds from each of the cold and hot water tanks to the pump, and then to the shower. The advantage of this is that the feeds to the (thermastatic) shower will be well balanced, but the disadvantage is that the cold tank will be emptied very quickly, feeding both the hot tank and the pump-cold-feed at the same time whilst the shower is on. I could, I suppose, fit a larger cold tank in the loft to help with this issue.

2) Fit a standard 2-3 bar negative head single pump to the hot water only shower inlet (with one way valve), and connect in the cold rising main (with regulator) to feed the shower as well. The advantage of this is that the cold water tank (feeding the hot) has a better chance of not running out, but I'm worried about whether I'm setting myself up for a fall with potential pressure disparities between the shower supplies, and also whether the mains flow will be enough to feed the shower (flow being different to pressure of course).

Does anyone have any advise about which way to go?

Thanks in advance,

Simon

[Piersman2]

SimonD said:

Hi all,

Does anyone have any advise about which way to go?

Thanks in advance,

Simon

I did similar a couple of years back. Fitted a pump and thermostatic shower. I had the same concern as you, that the existing cold water storage tank wouldn't be sufficient for a decent shower.

I went the route of fitting a second storage tank, in parallel, in the loft so that the pump had a decent reservoir from 2 tanks to draw from.

I also spotted your other question about the weight. I checked that the area I was locating the tank was over a wall beneath so that the weight of the tank bearing on the beams would be supported by the wall beneath. Alternatively you could spread the weight of the tank across more beams by using some wooden supports runnign across the beams to put the tank on. I would suggest that so long as you don't poition the tank right above the middle of a room you should be OK.

But this advice is just that, advice, and I accept no liability

[SimonD]

Good advice there, thanks...