2nd pump or bigger pump?

[phillmyglass]

This is my 1st post on here so hope I'm not asking things that have been asked a thousand time before. Here goes.
I am wanting to beef up the shower in the main bathroom, it's a gravity fed system to that one and has a small pump fitted to the en-suite shower, running off 15mm feeds. I am wanting both showers to be pump fed with the possability of using both at the same time?
Should I fit another small pump (the shower needs 2 bar min) on independant feeds, or fit a bigger pump and swap the 15mm feeds to 22mm? The bigger pump would use less space than 2 small ones.
Will the small cold tank in the loft be big enough to run 2 showers at once?
Can you recomend pump sizes that will do the job?

 

[PlumbBobBob]

how small are we talking about for the loft tank? i would get a larger pump that runs on 22mm pipes

you have to remember that the loft tank feeds the hot cylinder as well as the cold to the pump.

 

[mountainman]

Also bear in mind your hot storage might not be adequate to feed two pumped showers for more than a few minutes.

 

[phillmyglass]

The tank is about a foot by about 18 inches, I think it's a standard small one ( like the central heating header tank size). I am not sure but think that one only feeds the en-suite shower. Thanks.

 

[PlumbBobBob]

you really need a bigger tank than that to feed a shower to be honest. 4 gallons is too small.