a) Get yourself a combi friendly shower unit.
b) A combination boiler is only really suitable for supplying x1 hot tap at a time, some models like the Vaillant AquaPlus can supply several, but even they are limited as they can only supply say x2 taps for upto 5 minutes or so.
There's not much else I can advise, your installer should have warned you of the differences between combi's and system boilers at the time of sale.
GasAid.co.uk
January 2007
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