i have just had a condensing combi gas boiler fitted and was not not to worry about turning off the rads in rooms not being used as it will not cost me anymore money.
is this right? will cost the same to leave all on in the winter and not turn any off in rooms not in use/
dont want to get a huge gas bill through miss information
Surely, the amount of gas you burn for heating will depend on where the room thermostat is and at what temperature it is set at? It is the room thermostat that tells the boiler when to switch on and off. If the thermostat is in your sitting room, keep the doors and windows closed in order to conserve heat, and try turning the thermostat down a bit and learn to live with a slightly lower temperature (put warmer clothes on!!).
to put it simply the boiler sends out hot water from the boiler, it flows through the pipes and radiators and returns to the boiler, as it flows through the radiators the water loses its heat to the rooms, the more radiators you have turned on the more heat lost from the water, when it returns to the boiler the thermisters measure the temp of the water and bring the burner on until it is back up to the set temp, therefore the more rads on the more gas you burn.
You must keep the radiator on in the same area where the thermostat is and it must not have a thermostatic valve. If you do set thermostatic valve to lower temperature than thermostat then you can block the system. i.e. thermostat asks for more heat and radiator says ' I do not need heat' then boiler tries to push heat through a closed valve. Not very good.