The System Sensor 5621 is a commercial-grade dual-circuit mechanical heat detector designed for high-reliability fire detection in environments where traditional smoke sensors are prone to nuisance alarms. This 135°F fixed temperature and rate-of-rise heat detector utilizes two independent circuits to trigger both local alarm systems and auxiliary devices like fans or door closers. The Rate-of-Rise (ROR) element responds to temperature increases exceeding 15°F per minute, while the 135 degree F fixed heat alarm point provides fail-safe activation via a non-resettable fusible alloy. Built for versatile installation, it features a reversible mounting bracket compatible with single-gang, octagonal, and 4-inch square back boxes using a plaster ring. The alphanumeric lettering identification on the exterior ensures field technicians can quickly verify the model’s 135°F/57°C rating and FX/ROR activation method. Its post-activation collector drops upon triggering, providing a visible indicator for troubleshooting and device replacement in the field. Key Benefits for the Contractor: Dual-Circuit Logic: Provides simultaneous control over fire alarm panels and secondary auxiliary circuits for comprehensive building automation. Superior False Alarm Resistance: Ideal for kitchens, garages, and high-humidity areas where particulate matter would cause smoke detector malfunctions. Easy Field Identification: High-visibility alphanumeric markings and a mechanical drop-pin collector allow for instant identification of activated units. Broad Mounting Compatibility: The flexible reversible mounting bracket streamlines installation across various electrical box configurations without extra hardware. Restorable ROR Element: The rate-of-rise component can be field-tested with a heat gun for routine maintenance while the fixed temperature element remains on standby. Common Questions: Can the System Sensor 5621 be reset after a fire event? The rate-of-rise portion of the sensor is self-restoring for testing purposes; however, once the 135°F fixed temperature thermal sensor is activated, the fusible link has melted and the entire unit must be replaced. How does the dual-circuit design benefit HVACR and fire safety systems? The dual circuit allows a single detector to report a fire to the main FACP while simultaneously initiating a thermal sensor response to shut down HVAC blowers or close fire dampers via the auxiliary circuit. Is this detector rated for residential use? While commonly used in commercial property protection, the 5621 is suitable for any non-life-safety applications where mechanical heat detector technology is preferred over smoke detection due to environmental conditions. Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.
