Additional present day thermostats have coiled bimetallic strip components, along with the contacts are sealed behind glass to guard them from Filth. Because the temperature drops, the bimetallic elements start to uncoil. The force exerted via the uncoiling of the elements separates a stationary steel bar from the magnet at http://emilioswmon.digiblogbox.com/20656114/the-best-side-of-emergency-heating-repair