| 摘要 |
<p>This relates to a thermodynamic electronic actuator for shutting down operation of a heating and/or air conditioning system for a building or other enclosed space, when doors are left open or ajar. The actuator circuit comprises a normally-closed door jamb switch (11) which initiates operation of a count-up timer (40) to cut off power to the thermostatic control (60) after a first preselected period, whenever a door is left open, and to restore power to the thermostatic control (60) after a second preselected period, under control of a count-down timer (50), assuming the doors are again closed.</p> |
