Well, no contact from the fitter as yet although an electrician was here fitting some opentherm controls as part of the deal. Checked again at the outside tap and confirm it was still 22lpm. I did try the washing machine inlet hose and that didn't quite match the 22lpm and was around 17.5 but I think by looking it was really restrictive with a very tiny hole at the end. Either way it exceeded 9lpm.
Just a few feet upstream from the stopcock are the two isolation valves....one on the cold supply and the other on the boiler supply....so as suggested maybe the boiler supply one is faulty? I believe these were full bore when fitted. From looking they're both open it would seem fully.
The prv has been removed that was used to limit the istor boiler feed to 2 bar so there is nothing else on this feed to the boiler....just a left hand turn which then leads straight to the boiler.
The fitters have pieced back some plasterboard behind the boiler so I wonder if there is something restrictive they've fitted beyond this hidden out of sight?
John.g you are correct - the bathroom tap is a mixer tap.
I will keep this updated anyway until we get this resolved as I appreciate everyone's help.
Just a few feet upstream from the stopcock are the two isolation valves....one on the cold supply and the other on the boiler supply....so as suggested maybe the boiler supply one is faulty? I believe these were full bore when fitted. From looking they're both open it would seem fully.
The prv has been removed that was used to limit the istor boiler feed to 2 bar so there is nothing else on this feed to the boiler....just a left hand turn which then leads straight to the boiler.
The fitters have pieced back some plasterboard behind the boiler so I wonder if there is something restrictive they've fitted beyond this hidden out of sight?
John.g you are correct - the bathroom tap is a mixer tap.
I will keep this updated anyway until we get this resolved as I appreciate everyone's help.