Central heating upstairs works fine but downstairs cold.
I turned the radiator valves off upstairs and the downstairs heated up.
I then opened the radiator valves upstairs and all worked, but noticed same happened after hot water for shower used (Maybe a coincidence?).
Boiler pressure is 1.2 bar-(recommended in wocester bosch highflow manual is 1.5 bar) but when I open water inlet to boiler to increase pressure all that happens is hot water release from boiler overflow. I use to be able to increase pressure up to 1.9 bar until recently but pressure has dropped to 1.2 over a period of about 5 weeks. Any expert advice would be appreciated!