Adding a thermostat to my heating system

[joegina]

I have an oil fired heating system with no thermostatic control. Each radiator has a 1-5 scale valve on it and the boiler can be ON/OFF/On once a day/On twice a day. Is there any reason why I can't introduce a thermostat into this system? I imagine the boiler coming on at approx 6 am and going off at 9 pm, with us turning the thermostat up and down during the day.

[sheerdelight]

Those sound like thermostatic valves if they are numbered. There must be some form of thermostat on the boiler otherwise it would be firing all the time and the water in the system would overheat!

[buildersmate]

There is always a thermostat on the boiler, to turn off the boiler when the water temperature in the water vessel reaches typically 75 degrees C. Some boilers have a dial gauge so this can be adjusted up/down a bit.
However you are right that with the set-up you have, there is nothing to prevent boiler cycling (constant on/off running for no useful purpose) when the temperature of the rooms is satisfied but the timer is within a time period that is regarded as 'on'. With an additional (electrical switch) thermostat to tell the system that the there is no demand required for heat, one can force the system not to cycle.
So you can introduce a thermostat but you will probably require a heating engineer or an electricain to work out for you where to put it into the circuit.
I would expect you to save quite a bit of energy of doing this - no system installed these days is allowed to be controlled in this rudimentary fashion (under Building Regulations).

[joegina]

Thanks Buildersmate, Once he's back to work I'll speak to the electrician/