SBS-C3H8: Propane Gas Detector

Propane Sensor and Monitoring System

The SBS-C3H8 Propane Gas Detector is a propane gas detection system with visual and audible alarms and 25%LEL and 50%LEL propane relays.

The system comes complete with the main control, a highly accurate propane gas sensor and a 25 ft. cable. This unit can be powered with AC and/or DC power and can be mounted directly to a wall or to an electrical box, making it extremely versatile and very user-friendly.

The SBS-C3H8 includes relays for remote connection to alarm/monitoring systems and for control of external relays or an exhaust fan.

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Application Information


  • Protects life, property and company profits
  • Ideal for remote locations
  • Fail safe mode in event of loss of power
  • Up to three (3) sensors can be installed to main control to meet space coverage requirements


  • Universal power inputs: 110/220 Vac and/or 12–48 Vdc input
  • Strobe light for visual alerts
  • Sensor status indicator LEDs on the main control
  • Modular design for optimal placement of sensor(s)


  • Wall or 2-gang junction box mountable
  • Mechanical relays are easily accessible:
    • Warning 25% relay, 15 A @ 120 Vac; 10 A @ 277 Vac; 10 A @ 28 Vdc
    • Alarm 50% relay, 0.5 A resistive @ 28 Vdc, 0.5 A @ 125 Vac
  • Redundant power supply capability; dual AC and/or DC power supply connections (DC power supply will operate as backup power source)
  • Indicator LEDs can be tested by pushing the red “TEST” button
  • Sensors can be tested in the field with the P/N C3H8-TESTKIT

Detector can operate exhaust fans and building alarms / SCADA systems:

battery gas sensor diagram

Warning Settings: Should the concentration of propane gas in the air surrounding the sensor reach 25%LEL by volume, the “25%LEL Warning” yellow LED will light up on the main control of the unit. In addition, the 25%LEL internal relay will energize and can be used to activate an external exhaust fan.

Alarm Settings: Should the propane gas concentration reach 50%LEL by volume, the “50% Alarm” red LED will light up, the strobe will flash and an audible alarm will sound. In addition, the 50%LEL internal relay will energize and can be used to activate a building management/alarm system (via SCADA/Modbus).

SBS-C3H8 Includes

  • Main unit
  • Propane sensor
  • 25 ft. cable
Dimensions 4.7" L x 4.7" W x 1.2" D (main control)
Power Supply(s) 110/220 Vac, 50/60 Hz and/or
12–48 Vdc (9–58 Vdc operating voltage)
Leak Detection Propane
25% LEL (Lower Explosive Limit) Dry contacts rated 10A/250 Vac
50% LEL (Lower Explosive Limit) Dry contacts rated 0.5A/28 Vdc

Parts & Accessories

SBS-C3H8 propane sensor and detector's calibration kit
Test Kit (international orders ship without compressed gas)
propane sensor with cable
Additional Propane Sensor with 25 ft., 50 ft. or 100 ft. Cable
SBS-Gas detector unit mounted with junction box
Unit can be powered with either AC or DC power and can be mounted directly to a
wall or to an electrical box, making it extremely versatile and user-friendly.
Additional mounting options in data sheet.
Accessory Ordering Information
Part No. Description
C3H8-SENSOR-25FT Additional propane sensor with 25 ft. cable
C3H8-SENSOR-50FT Additional propane sensor with 50 ft. cable
C3H8-SENSOR-100FT Additional propane sensor with 100 ft. cable
C3H8-TESTKIT Test kit (includes 25%LEL and 50%LEL propane, regulator, tubing and case) Note: cannot ship via air freight
C3H8-JB 4 11/16" x 4 11/16" 2-gang junction box
E190399 AC Cord 110 V, 10 A, 10 ft. with plug


  • Businesses
  • Warehouses (heating)
  • Hospitals
  • Restaurants
  • Food preparation
  • Propane fueled forklifts
  • Propane fueled vehicles
  • Agriculture / livestock
  • Homes
  • Gas fireplaces
  • Propane fueled back-up power systems