I have new TRV`s and no room thermostat. I have three radiators without TRV`s fitted. I read somewhere that these need to be kept on all the time, why is that and do all three have to be kept on ?
to protect your pump/boiler
u usually only need one that acts as a bypass (for when the other rads are off)so the pump is not pumping against nothing.but you can also fit an automatic bypass valve that does th same thing