I need to fit a new radiator valve on an upstairs radiator. Obviously I've isolated the radiator (as I've taken it off) but my question is what do I need to do to get the water level down in the system to enable me to do the valve work?
I've got a Biasi 24S (or oen of its variants) combi boiler. Is it a case of finding the drain valve on the boiler or would I be better suited isolating all but one of the downstairs radiators and draining the required amount from there?
Any help much appreciated.