Answer:
The Honeywell 851 Series operates on a 15 to 32 VDC loop with a maximum average standby current of 300 µA at 24 VDC and active alarm LED draw of 6.5 mA. The detector head measures 2.1 inches (5.3 cm) in height, weighs 4.8 oz (137 g), and is UL approved for 50 ft (15.24 m) center-to-center spacing.
The Honeywell Notifier 851 Series intelligent plug-in thermal detectors operate within clearly specified electrical, physical, and spacing tolerances designed for supervised industrial and commercial addressable fire alarm systems:
- Operating Voltage Range: 15 to 32 VDC peak over the supervised two-wire Signaling Line Circuit (SLC).
- Standby Current: 300 µA maximum average at 24 VDC (based on polling once every 5 seconds with LED communication blink enabled).
- Alarm Current: 6.5 mA maximum at 24 VDC with both LEDs latched on continuously.
- Physical Dimensions: Detector head height is 2.1 inches (5.3 cm). Overall assembly diameter depends on the selected base: 6.1 inches (15.5 cm) with the standard B210LP(A) flanged base, or 4.1 inches (10.4 cm) with the B501(A) flangeless base.
- Unit Weight: Shipping weight is 4.8 oz (137 g).
- Spacing Approvals: UL approved for 50 ft (15.24 m) center-to-center spacing on smooth ceilings in accordance with NFPA 72 guidelines; FM approved for 25 x 25 ft (7.62 x 7.62 m) grid layouts.
- Operating Humidity: 10% to 93% relative humidity (non-condensing).
