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Gentex GN-503F, 120V AC Combo Photoelectric Smoke/CO Detector, Form A/C Relay, 9VDC Backup
Gentex GN-503F, 120V AC Combo Photoelectric Smoke/CO Detector, Form A/C Relay, 9VDC Backup

Gentex GN-503F, 120V AC Combo Photoelectric Smoke/CO Detector, Form A/C Relay, 9VDC Backup

Manufacturer Part#:918-0007-002
Our Part#:918-0007-002
Stock Status: In Stock
Retail Price:$105.85
Your Savings:$23.43(22%)
Your Price:$82.42









Feature 5


Feature 7

Product Type:Combination Detector|Input Voltage:120VAC|Detection Type:Photoelectric + CO|Connection Type:Hardwired|Intended Use:Residential,Commercial|Battery Backup:Yes|Interconnect:No
All Gentex items will ship directly to our warehouse and then to the customer causing extended lead time


  • 120VAC/9VDC
  • Photoelectric Smoke Sensor and Electrochemical CO Sensor
  • UL 217 and UL 2034 Listed
  • NFPA72 and NFPA720 Compliant
  • Horn Frequency 3100Hz
  • Temporal 3 Sounding Pattern for Smoke Annunciation and Temporal 4 Sounding Pattern for CO Annunciation
  • Optional Auxiliary Form A/Form C relay contacts (GN-503F Model)
  • Quick Disconnect Wiring Harness
  • Push Button Self Test Feature
  • Push Button Functional Test
  • Non-Latching (self restoring)
  • Dualink® ? Tandem Interconnect with all Gentex Tandem Capable Alarms
  • Low or Missing Battery Indicator
  • End of Life Signal Indicating CO sensor has Reached Depletion State
  • Mounting Hardware Adapts to Standard Junction Boxes


The GN-503 (120VAC/9VDC) Series of combination photoelectric smoke and electrochemical sensor carbon monoxide alarms are for use as an evacuation device in all dwelling units, including but not limited to homes, apartments, hospitals, hotels, motels, and other commercial occupancies. The GN-503 Series is listed in compliance with UL 217, UL 2034, for installation per NFPA 720 and NFPA 72.

Available in two models, the GN-503 Series is engineered to virtually eliminate nuisance alarms and deliver outstanding performance wherever reliable smoke and CO protection is required.

The GN-503 Series is provided with a 9VDC alkaline battery for electricalback-up in the event building power is lost. The battery impedance is verified and thealarm provides a low or missing battery warning. The battery drawer provides easyreplacement without removing the unit from the wall or ceiling.

The Gentex GN-503 Series are provided with a self test and functionality test feature.The self test notifies if the smoke/CO alarm is functioning properly or needsattention. The functionality tests that the smoke/CO alarm is operating properly. The self and functionality tests are in compliance with NFPA 72 and UL Standards.

Features of the combination alarm series include DUALINK® differentiating tones indicating a smoke alarm (temporal 3) or a CO alarm (temporal 4), tandem capabilities with all Gentex tandem interconnect capable alarms. Options include aForm A/Form C dry contacts for remote annunciation and connection to a protected premises alarm system to provide a supervisory/trouble signal. The GN- 503 provides Temporal 3 evacuation tones for smoke alarms and all units provide Temporal 4 tones for CO alarm annunciation. The Temporal 3 evacuation tone for smoke alarm will take precedence of the Temporal 4 tone for CO alarm.

Electrical Specifications

Operating Voltage 120VAC, 60Hz
Operating Current .045 amps
Operating Current (Relay Options) .070 amps
Operating Ambient Temp Range 40°F to 100°F
Alarm Horn Rating 85dBa at 10 feet
Auxiliary Relay 1 Form A & 1 Form C (0.6 amp)
Size Diameter: 6.25 in OA (5.75 in. at the ceiling)
Secondary Power Source Alkaline 9VDC battery Duracell MN 1604
CO Sensing Cell Electromechanical Cell

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