The room thermostat is your 'output' (as it was marked on Creda heaters years ago). The other dial is your 'input'. What happens is the more you turn up the input, the more heat is stored in the bricks. Your room thermostat (output) should remain relatively the same all the time, that has a damper to control how much heat it puts out into your room. The input varies on the time of year - if the damper is open full and you've used very little input, it'll be cold pretty quickly. Hope that helps answer the question.
Stuart, September 2006
