I managed to break our wall thermostat while decorating the hallway 4 years ago and have finally managed to get 'round to purchasing a new one.

Mrs G is most impressed with my rapid response, and reckoms I should werk for the council.

Can I simply change it over, as the wires look tiny, without disconnecting the leccy with it presumably being low voltage like the telephone, or am I risking blowing meself and Growler Towers up by simply plundering ahead with the mains still switched on ?
Nick needn't bother replying, thank you.
