Overview / Design Principle:
This unit is a two-switch, non-indicating temperature control with unlimited differential setting capabilities between switches. It is used where two fixed temperatures are specified as control points and where a change or adjustment of those points is seldom required. UL and CSA listed.
Temperature setting on the N79-79 may be set by the factory or the end user by adjusting screws inside the control case in conjunction with an accurate temperature-sensing device placed adjacent to the thermal sensing element.
Due to the construction of the instruments, the switches are held in a depressed position and revert to their normal, or free state, in response to a temperature increase.
Therefore, as a mechanism function in this control, a normally open two-wire switch, or the normally open side of a three-wire switch, operates as a normally closed circuit when the bulb temperature is below set point.