Low mains pressure for combi boiler

[ady]

Hi.
I am looking to have a combi boiler installed in my 2 bed 1 bath terraceed house to provide for heating and hot water. The house is located at the top of a hill and the mains water pressure and flow is not great. As I already have a water tank in the loft would there be any problems with feeding the boiler from this tank to provide a consistantly good pressure and flow rate. I realise that if hot water were to be run for a long time the tank would theoretically loose its reserve but it is a large tank and I am sure would have no problem filling a bath and supplying a washing machine etc. simultaneously.
Thanks for any opinions.
Regards - Ady

 

[ChrisR]

You could make it work. Do you know what themains pressure & flow actually are? (ask the water co for the pressure)

The flow from the loft tank down to the combi and to the bath might well be a bit slow, but Grundfos do a small pump (less than £100) which is designed for this sort of situation. iirc they add about 0.7 bar (7 metres head).
You'll still need to pick your cmobi carefully, if again memory serves the Vaillants will give their full HW output from 0.5 bar.

 

[ordo]

ideally all combis should be fed from mains pressure thus doing away with storage tanks.best solution is to ask water board to get mains turned up.feeding combis from storage tanks runs into problems.last resort.

 

[kevplumb]

ideally all combis should be fed from mains pressure thus doing away with storage tanks.best solution is to ask water board to get mains turned up.feeding combis from storage tanks runs into problems.last resort.

ideally the poster wouldnt be asking smart ar*e