This is the standard THERMOFLEX™ single circuit, Normally Closed contacts detector, in which the connectivity is modified with pigtail leads that extend through a seal plate.This provides for enhanced protection against corrosive or moisture-laden environments.

Combination Rate-of-Rise & Fixed Temperature

The Model Number prefix “CR” indicates that the detector is a combination Rate-of-Rise and Fixed Temperature,(often referred to as “Dual-action”), unit.  The Rate-of-Rise function allows the detector to open its contacts when the temperature at the ceiling increases at a rate of 8.4 Celsius degrees (15 Fahrenheit degrees) per minute. The opening of the contacts can initiate a fire alarm condition. The Fixed Temperature portion consists of a spring-loaded plunger held in place by a eutectic solder that will fuse at the specific temperature (in Fahrenheit degrees) as indicated by the Model Number i.e. 135,165,200 and 285 degrees.
 
Fixed Temperature Only
The Model Number prefix “CF” indicates that the detector is Fixed Temperature Only, and will therefore not respond to a rate of temperature increase but will operate when the detector fuses at the prescribed (Fahrenheit) temperature as indicated by the model number, i.e. 135,165,200 and 285 degrees.  This detector is referred to as “Fixed Temperature Only, non-restorable”.