Hi,
How old is the system? [color=red]about 15 i think [/color]
How high is the F+E tank in the loft, is it sitting on the ceiling? yes
Also what size pipe have they used for the radiators, in particular downstairs? 15 mm in the living room . 10 mm in the kitchen
Does the pipework drop down to feed each or a few radiators, or is there only one drop feeding al the downstair's circuit? it has two drops one for the living room and one for the kitchen . they ore the only rads on the ground floor
I take it, you now have power to the 3 port, so you can flick it to heating only, and with all the upstairs radiator's turned off on BOTH side's the boiler is quickly cutting out on max temp? yup
Sam