I've searched and answered a few of my own questions I think but I've basically been used to combi boiler houses/flats for all my renting/owning life and now suddenly have a conventional system. The one part I can't work out entirely is the bathroom radiator. Currently have only the hot water system operating and no central heating timers set. When the HW timer is on the radiator in the bathroom is getting ridiculously hot. Reading some previous topics I'm guessing (but haven't confirmed) that this radiator is connected to both CH and HW circuits to provide heat to that room all year (which in principle is fine). However I wondered that because it gets so hot, regardless of how much I open or close the valve, that with a small inquisitive child it's a bit of a problem (plus it's right next to the toilet so it makes reading the paper on the can no longer a pleasure). So can I add a TRV to this radiator, it's the only one in the house without one, my concern is I read somewhere else that you should always have one rad without the TRV as a release or something i.e. so all rads can't be off at same time? I'm clueless on conventional systems so no idea what I can and can't do within reason.
TIA