Combi shower/pressures

[hardatwork]

Can you have a thermostatic shower run off a combi (mains pressure hot) but cold water from a cistern in the loft.

Or ideally, is a direct system needed in the house so cold water is also at mains pressure to balance it out?

 

[seco services]

mains cold/hot balanced pressures.

 

[hardatwork]

ok so really it's not a good idea to have a combi boiler istalled with an indirect water supply to the house is it, as hot will be at a higher pressure, apart from in the kitchen?