System Sensor 5601P Heat Detector, 135F Fixed Temp/Rate-of-Rise, Single-Circuit, Plain Housing

The System Sensor 5601P is a commercial-grade, single-circuit mechanical heat detector designed to provide fixed-temperature and rate-of-rise fire detection for compatible hardwired fire alarm and security systems. Part of the Honeywell System Sensor 5600 Series, the 5601P activates when ambient temperature reaches 135 F (57 C) or when the surrounding temperature increases at approximately 15 F (8.3 C) per minute. Its combination sensing mechanism incorporates a self-restoring rate-of-rise element, non-resettable fixed-temperature element, and normally open alarm contacts for connection to compatible initiating device circuits. The detector features a plain white housing, reversible mounting bracket, and non-polarized screw terminals supporting 14-22 AWG wiring. Measuring 4.57 inches in diameter and 1.69 inches high, the 5601P supports surface or flush mounting to standard electrical boxes. The device is UL 521 listed and has a manufacturer-published maximum spacing of 50 by 50 feet on 10-foot ceilings, subject to applicable installation requirements. Designed for kitchens, garages, utility rooms, warehouses, and other locations where smoke detection may be unsuitable due to environmental conditions, the 5601P provides dependable mechanical heat detection without requiring external operating power.

System Sensor 5601P 135 F Fixed-Temperature and Rate-of-Rise Mechanical Heat Detector

The System Sensor 5601P Mechanical Heat Detector provides temperature-based fire detection for residential, commercial, and institutional properties requiring a conventional hardwired initiating device. Manufactured by Honeywell System Sensor as part of the 5600 Series mechanical heat detector family, this single-circuit model combines 135 F (57 C) fixed-temperature detection with a 15 F (8.3 C) per minute rate-of-rise sensing mechanism. The dual-method sensing arrangement allows the detector to respond either when surrounding air reaches its predetermined temperature threshold or when the ambient temperature rises rapidly enough to activate its pneumatic sensing chamber. Unlike photoelectric or ionization smoke detectors, the 5601P monitors heat rather than airborne smoke particles, making it suitable for appropriately designed installations in kitchens, garages, utility rooms, mechanical spaces, and industrial-support areas where dust, cooking aerosols, or other environmental contaminants can interfere with smoke detection. The detector features a plain white housing without prominent exterior temperature lettering, providing a discreet appearance for residential ceilings and commercial interiors. Its conventional normally open contact output supports integration with compatible fire alarm control panels and supervised initiating circuits.

The 5601P incorporates two distinct mechanical thermal sensing mechanisms designed to respond to different heat conditions. The fixed-temperature element activates at 135 F (57 C) using a fusible alloy that releases an internal spring-loaded contact when the specified temperature is reached. This activation permanently changes the sensing mechanism, making the fixed-temperature element non-resettable. The rate-of-rise mechanism responds to temperature increases of approximately 15 F (8.3 C) per minute through a sealed pneumatic chamber and calibrated vent that detect rapid thermal expansion. Unlike the fixed-temperature element, the rate-of-rise sensing mechanism is self-restoring and can be functionally tested according to the manufacturer's instructions. The detector provides single-circuit, normally open electrical contacts with resistive ratings of 3 amps at 6-125 VAC, 1 amp at 6-28 VDC, 0.3 amp at 125 VDC, and 0.1 amp at 250 VDC. Physical dimensions are 4.57 inches (116 mm) in diameter by 1.69 inches (43 mm) high, including the mounting bracket, with a weight of approximately 6 ounces (170 grams). The specified maximum installation temperature is 100 F (38 C), and the operating humidity range is 5-95% relative humidity, non-condensing. The 5601P is UL 521 listed for heat detectors used in fire protective signaling systems.

For conventional fire alarm and property protection applications, the System Sensor 5601P provides a normally open initiating contact that closes when either thermal sensing mechanism activates. This contact closure allows a compatible fire alarm control panel or security system zone to recognize a heat alarm condition and initiate the programmed system response. Because the sensing mechanism is mechanical, the detector does not require a separate power connection to operate its thermal elements; however, the connected alarm system supplies and supervises the initiating circuit according to its electrical design. System Sensor specifies a UL-listed maximum spacing of 50 feet by 50 feet (15.24 by 15.24 meters) for installations with 10-foot ceilings, with reductions required where ceiling height, construction features, airflow, or applicable NFPA 72 provisions affect detector placement. The combination of fixed-temperature and rate-of-rise sensing provides two activation methods within a single device, supporting detection of both sustained elevated temperatures and rapid increases in heat. The detector also incorporates an external heat collector that drops when the fixed-temperature element activates, providing a visible indication of permanent thermal activation. The 5601P differs from the System Sensor 5603, which provides 135 F fixed-temperature detection without rate-of-rise sensing, and the 5602, which combines rate-of-rise detection with a higher 194 F fixed-temperature rating. The related 5621 offers comparable 135 F fixed-temperature and rate-of-rise detection with dual-circuit electrical outputs.

Installation of the System Sensor 5601P single-circuit heat detector uses a reversible mounting bracket designed for both surface-mounted and flush-mounted electrical box configurations. The mounting bracket accommodates 3-1/2-inch octagonal boxes, 4-inch octagonal boxes, single-gang electrical boxes, and 4-inch square boxes fitted with square-to-round plaster rings. The detector attaches to the bracket through a quarter-turn locking mechanism, allowing removal for inspection and replacement without disturbing the mounting hardware. Its non-polarized SEMS screw terminals accept 14-22 AWG conductors, supporting connection to compatible supervised conventional initiating device circuits. During installation, technicians must verify the specified temperature rating, applicable spacing requirements, wiring arrangement, control panel compatibility, and environmental conditions. The manufacturer recommends periodic functional testing of the self-restoring rate-of-rise element using an appropriate controlled heat source, with care taken to keep the applied temperature below the 135 F fixed-temperature activation threshold. If the fixed-temperature element activates, the detector cannot be reset and must be replaced. For storage and transportation, System Sensor specifies that temperatures must remain below 122 F (50 C) to prevent unintended activation of the fixed-temperature element. The 5601P includes a three-year limited manufacturer warranty and is intended primarily for property protection or supplementary detection applications where conventional smoke detectors may be impractical. Combining mechanical dual-method thermal detection, conventional hardwired compatibility, flexible mounting options, and a compact white enclosure, the System Sensor 5601P provides a reliable heat detection solution for appropriately designed commercial and residential fire alarm installations.