I am a householder not a plumber.
I need to replace my boiler (condensing), and thinking of a combi if possible. Currently the hot water system is open vented with tank in the converted loft on 2nd floor and the central heating is pressurised, with the hot water tank and pump and expansion vessel on the ground floor next to the boiler.
The hot water and heating pipes already run from the hot water tank which is next to the boiler so it be easy to connect up this. However the cold water to the upper floors (one bath, two showers, two sinks) runs from the cold water tank in the loft. Would these need new pipes from the mains ? As a mains pipe already runs up to the cold water tank , is it just a matter of connecting this mains pipe in the loft to the cold supply pipes in the loft ?
I will be getting some quotes from heating companies but just want to know the right questions to ask. I expect there will be differeing views on whether my house is not small enough for a comi.