Each model is a normally open device designed especially for fire detection and alarm systems. These rate compensation type detectors are available in either 135°F or 194°F ratings. All four basic models are self-restoring, hermetically sealed, shock and corrosion resistant, and are tamper-proof. All models operate on the principles of a rate compensation detectors. The detector consists of a high expansion aluminum tube which encases two insulation struts with opposing open constant points. The high expansion sensing shell and the expansion struts have a different co-efficient of expansion. A slow rate of temperature rise allows the heat to penetrate the inner expansion struts. Therefore, the tubular shell and the struts expand slowly until the total device has been heated to its rated temperature level of 135°F or 194°F. At this point, the silver contact points close which initiates the alarm. When subjected to a rapid temperature rise there is not as much time for heat to penetrate the inner strut. The rapid lengthening of the shell allows the struts to come together at a lower level which compensates for thermal lag inherent in conventional fixed temperature detectors. When the surrounding air temperatures go below the rated temperature level, the shell contracts which forces contacts to open, which automatically resets the detector.

Model Descriptions

Model 302
For interior mounting in any atmosphere that is compatible with terminal screw type connections.

Model 302-ET
Hermetically sealed for moisture proof or dust proof installations. Requires no special back box. Has plastic
hexagonal grip bushing with 1/2” conduit threads hub cover for any outlet box. Must be hand tightened only. For indoor and outdoor use. Protect from sunlight and adverse conditions

Model 302-EPM
Explosion-proof for installation in hazardous locations. Has hexagonal grip bushing with 1/2” conduit threads for attachment to threaded hub cover of series JL fixture fitting as manufactured by Killark Electric Co., or equal. Must be hand tightened only. For interior use.

Model 302-AW
Hermetically sealed for moisture proof or dust proof installations. Requires no special back box. For indoor and
outdoor use. Protect from direct sunlight and adverse weather conditions