Fit a booster pump to feed elec. shwr from cold water tank

[TD1264]

Hi ... I hope you can help?
I recently paid to have all my electrics upgraded so as I could upgrade to a 10.5Kw electric shower (all Part P approved etc and no problems).
I then purchased the shower - a Galaxy Aqua 4000.
We had numerous problems - shower either too hot or too cold, no "force" behind the water etc. Called the shower people out and they said we were "right on the limit" with regard to the pressure needed for the shower to work properly.
So... next plan is to fit a single impeller pump and feed the shower from the cold water tank instead of the mains.
Question 1 - what size cold water tank would I need (current is 91Litres/20 gallons) ?
Question 2 - what pump would I need ? 1.5 bar ?
Question 3 - anyone know any website with intructions on how to do all this?
Many thanks for your help!!
TD1264

for info : Galaxy Aqua 4000 : minimum recommended runnin water pressure to which the shower may be connected is 15lb/sq in (1Bar). Running pressure at 8 litres per minute. Maximum static pressure recommended is 150 lb/sq in (10 bar). ... Minimum running pressure must be obtained at 11 litres per minute for the 10.5kw unit

 

[chrishutt]

Sounds OK in principle, but you need to check that the initial very slow flow through the shower would be sufficient to trigger the flow switch on the pump, yet not trigger a low-pressure cut out on the shower. Could be tricky...

The feed tank could be quite small because it's likely to refill at least as fast as an electric shower would draw water out. 1.5 Bar pump should be OK, but when you know the flow rate through the shower you can check with the pump manufacturers on what pressure would be maintained with that flow rate.

 

[grrinc]

A negative head kit could be a solution to ensure the pump activates. I know salamander pumps can have a neg kit fitted retrospectively.

 

[Fluffster]

Am I missing something here would a mains feed not satisfy your needs and be a lot cheaper.
Pete

 

[TD1264]

Hi guys, thanks for all the feedback/advice so far.......but.....

Chrishut.......how would I go about checking that the initial very slow flow through the shower would be sufficient to trigger the flow switch on the pump, yet not trigger a low-pressure cut out on the shower ??

Fluffster - the shower is already fed from the mains, and the pressure is not constant enough to supply the shower properly.

Thanks again!.......

 

[chrishutt]

...how would I go about checking that the initial very slow flow through the shower would be sufficient to trigger the flow switch on the pump, yet not trigger a low-pressure cut out on the shower ??.

That's why I said it would be tricky. You won't know what flow you'll get through the shower from a tank until to install it. You'd be better off looking at a new shower - some electric showers, with a built in pump, are designed to run off a tank supply.

 

[TD1264]

Thanks "Chrishut".... I might just do that! May save some money and a whole lot of bother!

 

[simond]

You could fix it with an accumulator on the cold water side.

This would only need to be a 100 litre actual capacity unit or so, you could put in the roof.

No noise, flow rate would increase, and the shower is unlikely to be affected in the way that a pump could confuse the sensors (if this shower is at all intelligent).

 

[Nige F]

Been, done .used a S£uar£ £urner single impeller one with neg head kit.........years ago so the details have faded Worth giving Stuart Turner a call and getting 0% credit card out