Thermotech 302-ET-135 Weatherproof Heat Detector

The Thermotech 302-ET-135 is a rate compensation heat detector. This detector resets once the temperature goes under the protection level. Each Thermotech 302-ET-135 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 come self-restoring, hermetically sealed, shock and corrosion-resistant, and are tamper-proof.

In fact, all models operate on the principles of rate compensation detectors. The detector consists of a high expansion aluminum tube that encases two insulation struts with opposing open constant points. Besides, the high expansion sensing shell and the expansion struts have a different coefficient of expansion. A slow rate of temperature rise allows the heat to penetrate the inner expansion struts.

Also, detectors have a smooth ceiling UL rating of 50’ x 50’ (2500 sq. ft.) on 8 to 10 ft. ceilings. Detectors, hub covers, or outlet boxes must never be install in direct sunlight. Refer to NFPA Standard 72 for spacing and other considerations.

Features / Specifications

• Hermetically sealed and explosion-proof options
• Horizontal or vertical mounting ability
• Select models available for indoor and outdoor use
• Aluminum tubing with silver contact points