Weatherproof Heat Detector Thermotech 302-ET-194

The Model 302-ET-194 is hermetically sealed for moisture-proof or dust-proof installations. Requires no special back box. Has plastic hexagonal grip bushing with 1/2” conduit threads for attachment to threaded hub cover, or any outlet box. Must be hand tightened only. For indoor and outdoor use. Protect from direct sunlight and adverse weather conditions.



  • 194°F – All-Weather Vertical Mounting FM & UL
  • Eliminates False Alarms – The 302 Series do not respond to momentary temperature fluctuations below the selected temperature.
  • Universal Application – The 302 Series can be used in all areas for any type of occupancy.
  • Self-restoring
  • Hermetically sealed, shock-resistant, corrosion-resistant, and tamper-proof.


The 302 Series rate-anticipation heat detector responds and activates the fire alarm immediately whenever the ambient temperature reaches the preset temperature setting. Under rapid heat rise conditions, the rate-anticipation feature enables the detector to respond one to three degrees ahead of the setting. At the same time, however, it does not respond to momentary temperature fluctuations below the selected protection level, thus eliminating false alarms. When the temperature drops back down below the protection level, the detector automatically resets itself.

Application Information

302 Series detectors have a smooth-ceiling UL rating of 50′ x 50′ (15.24 x 15.24 meters) and are the only type of heat detectors having such a rating on both fixed temperature and rate anticipation.


Total Overall Length: 4-1/8″
Base diameter: 2″

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