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ST-48 Propane Combustible Gas Monitor

Item #: 95133


Product Summary

The ST-48 Combustible Gas Monitor is ideal for facilities that require continuous monitoring of propane. The enclosure is specifically designed to prevent an explosion. The monitor is well suited for environments such as warehouses, heating and cooling, alternative fueling stations, and any locations requiring LEL gas monitoring for combustible gases. The monitor is housed in a NEMA 4 explosion-proof enclosure suitable for Class 1, Group B, C, and D, Class 2, Group E, F, and G. PureAire’s durable, long-life LEL catalytic sensor will last 5-6  years in a normal environment without needing to be replaced.

  • LEL Combustible Gas Analyzer with 0-100% or 0-4% of LEL
  • Designed for Combustible Gases including Propane
  • Gas Sampling for Vessels or General Safety with Wall Mount
  • Explosion-Proof Enclosure
  • Non-Intrusive Calibration
  • Local Digital Display
  • 4-20 mA Analog Output
  • 2 Configurable High/Low Relays
  • Long Life LEL Catalytic Sensor Average, 5-6 years

The ST-48 LEL gas detector is housed in a NEMA 4 Explosion Proof Enclosure and is available for propane (C3H8). Capable of monitoring the percentage of LEL combustible gas, the ST-48 is a perfect monitoring solution for providing worker protection in warehouses, agricultural facilities, alternative fueling stations, the oil and gas industry, and other areas requiring hazardous monitoring for propane.

The instrument’s fault supervision circuitry continuously monitors for failed sensor cell and communication. Our sensor cell operation is continuously supervised 24/7, and when used with distributive control systems or PLCs, the monitor provides immediate fault identification.


Sampling Method Diffusion Cell
Gases Detected Hydrogen Sulfide (H2S)
Ethanol (C2H5OH)
Ethane (C2H6)
Ethyl Alcohol (C2H5OH)
Ethylene (C2H4)
Isopropyl alcohol (IPA)
Methyl Alcohol (MeOH)
Accuracy ± 1 % of Reading
Operating Temperature -32 to +50 ºC
-25 to +122 ºF
Display 3 1/2″ Digit LCD Digital Display
Sensor Type LEL Catalytic Bead
Sensor Life 2 to 5 years under Normal Conditions
Signal Outputs 2 alarm relays, 4-20 mA analog output, and fault relay
Power Requirements 2 24 VDC
3 Wire
Width 5.12 in
130.05 mm
Height 5.0 in
127 mm
Depth 8.0 in
203.2 mm
Weight 4.7 lb
Enclosure Nema 4 Explosion Proof Suitable for Class 1, Group B, C, & D

1 Contact PureAire for more gases
2 48 V DC, 3 Wire Available for LEL and Hydrocarbon Gases.

Additional LEL Monitor Accessories List Price
8 Channel Controller $2,595.00 US (P/N # 99058)
Horn and Strobe  $160.00 US (P/N # 42002)
Remote Display $375.00 US (P/N # 99091)

Self-Supervised Operation
The PureAire ST-48 Propane Combustible Gas Monitor incorporates sophisticated electronics that, when used in conjunction with distributive control systems or PLC’s enable you to quickly identify and correct major system faults. These enhanced self-diagnostic capabilities include missing cell and broken transmitter wiring. Should a system error occur, the ST-48 Combustible Gas Monitor outputs a 0 mA signal to remote alarm/control systems to immediately alert control room personnel.

ST-48 Propane Combustible Gas Monitor Literature

ST-48 Manual 

Gases Detected with PureAire Monitors

LEL Combustibles Layout 

LEL Monitor Layout 

LEL Monitor with Fan Relay