Just confusing myself

[pricega]

Can someone please help me decide on which boiler type to upgrade to.
I currently have a 20 year old conventional boiler with a hot water storage cylinder (it says grade 3 if that means anything) with 2 header tanks and I live in a 4 bed detatched house with 1 bathroom and 1 mixer shower. I am only getting 4 l/m flow out of the shower and would love to have more.
I fancied the 37CDi from WB so I could get away from heating more water than I use and upping the shower flow rate, but after measuring my mains cold water flow at 12 l/m down stairs I'm not sure it's the right thing to do any more.
You've probably guessed but I'm no plumber and I will be getting someone in to give me their advice and a price soon, but I just thought I'd get some professional opinions from here first.
All comments welcome.

 

[superdupergasman]

Is the 12ltr a min from kitchen tap??

and is that fed from the cold storage tank or the Mains??

Is the Main stopcock fully open, or screwed partial shut??

 

[pricega]

I know what you're thinking.
Yes it was measured at the utility sink which is fed from the mains water and the stop cock is fully open (including the one on the street). It's always been a bit slow, when I use a garden sprinkler I don't get very good coverage.

 

[mickyg]

The obvious answer is to keep with a cylinder and heat only boiler and use a shower pump to boost your shower pressure. If you want anything else your gonna need to improve your incoming pressure.

 

[TicklyT]

If you add a shower pump, you may need to consider increasing the cold water storage to avoid the pump syphoning the system dry.