The controller was wired up to operate two of the 3 zones - brown sticker - bedrooms, and silver sticker - basement, dining room, kitchen and hall. This was custom wired by the installer - obviously, there's no water heating.
The third zone, lounge and bathroom, is controlled by the room stat. All rooms have radiator thermostats except the lounge.
Now, this is all well and good and probably very clever, but the radiators seem to have a will of their own. All zones are on constant with stat valves fully open. The lounge is fine, always has been, and temperature modulates in line with the room stat. But the other zones vary between no heat, and luke warm as if providing background. Then, occasionally, they'll belt out heat. The dining room and kitchen have been cold all day. The basement's fine, well, 17C - where me and the computer live.
Apart from ask the installer, which is not an option, any ideas please?