The System Sensor 5601P is a single-circuit heat detector designed for commercial and residential fire alarm systems. It combines a fixed-temperature sensor set at 135°F with a rate-of-rise function, offering reliable detection of both slowly developing fires and rapid temperature increases. The normally open (NO) configuration ensures straightforward integration into existing alarm loops. Constructed with a durable polycarbonate housing, this unit withstands typical environmental stresses while maintaining consistent performance. Its compact, low-profile design allows discreet mounting on ceilings or walls, and the twist-lock base simplifies installation and maintenance. The 5601P operates effectively in temperatures ranging from -20°F to 150°F, making it suitable for diverse climates. Each unit undergoes rigorous factory testing to confirm sensitivity and response times, supporting long-term dependability. With a modest price point near $4.00, this detector provides substantial value for property managers, electricians, and DIY installers seeking cost-effective fire safety upgrades. The fixed-temperature mechanism is factory calibrated and does not require field adjustment, reducing setup complexity. The rate-of-rise function captures the sudden heat spikes characteristic of fast-flaming fires, complementing the fixed-temperature detection for comprehensive coverage. While not suitable for areas with frequent ambient temperature fluctuations, such as kitchens or boiler rooms, it performs reliably in hallways, storage areas, and living spaces. The 5601P meets UL 521 standards, ensuring compliance with industry safety requirements. Its corrosion-resistant contacts and sealed electronics protect against humidity and dust, extending service life in challenging environments. The detector’s low current draw minimizes power consumption on alarm panels, making it compatible with both conventional and addressable systems when used with appropriate modules. For routine testing, the unit supports a functional check using a heat source or test magnet, allowing verification without triggering false alarms from smoke or steam. The affordability of this model does not compromise build quality; the housing is impact-rated and the internal components are secured against vibration. End users can expect years of trouble-free operation when installed per manufacturer guidelines. The 5601P also includes a latching alarm indicator that remains illuminated after activation, aiding in identification of the initiating device during system troubleshooting. Replacement is straightforward due to the standardized base, and spare units can be kept on hand for quick swaps.

This heat detector balances essential detection capabilities with an exceptionally low cost, making it an economical choice for upgrading or expanding fire alarm coverage without sacrificing reliability or code compliance.