Hello everyone, newby tothe site. Hopefully somebody can help with my central heating issue. The central heating wont switch off using the roomastat or programmer. Unless u turn the boiler off. Hot water side works fine. But when boiler fired up again its ok until ch heating needs to be switched off it stays on again. its a y system with worchester greenstaer ri boiler with honeywell programmer and motorised valve and roomastat and hot waterstat. Just changed the head on the motorised valve and the valve is not seized. All I can tell you is when the ch and hw are switched off there is still 60volts coming out of the orange wire from motorised valve to boiler and pump.