LEL combustible e1460423315221

ST-46 Combustible Gas Detector with LEL Sensor, 0-100%

Item #: ST-46

Product Summary

Combustible gas detectors are used in workplaces that use combustible gas in order to secure worker safety, detect the location of any leakage, and measure gas concentrations. The enclosure is specifically designed to prevent an explosion. The monitor is well suited for environments such as power plants, refineries, natural gas locations, the oil and gas industry, and anywhere combustible, toxic gases are present. 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 4-5 years in a normal environment without needing to be replaced.

*This product has been discontinued. Please follow the link below to view the replacement model:

ST-48 Combustible-Toxic Gas Monitor

Please contact PureAire at (847)726-6000 if you have any questions or need assistance.


  • LEL Combustible Gas Monitor with 0-100% Range
  • Non-Intrusive One-man Calibration
  • Ex Proof Enclosure
  • Designed for Combustible Gases
  • Local Digital Display
  • 4-20 mA Analog Output
  • Long Life LEL Catalytic Sensor

The instrument’s fault supervision circuitry continuously monitors for failed sensor cell and communication line breaks. Plus sensor cell operation is continuously supervised 24/7 and when used in conjunction with distributive control systems or PLCs, provides immediate fault identification for a disconnected sensor cell.

The AirCheck LEL gas detector is housed in a NEMA 4 explosion-proof enclosure and is available for Ethanol, hydrogen, natural gas, methane, and more. Capable of monitoring the % LEL combustible gases, the AirCheck Ex is a perfect monitoring solution for providing worker protection in chemical plants, refineries, and other areas requiring hazardous classifications.

Sampling Method Diffusion Cell
Gases Detected 1 Ethanol (C₂H₆O)
Ethane (C2H6)
Ethyl Alcohol (C2H5OH)
Ethylene (C2H4)
Isopropyl alcohol (IPA)
Methane (CH4)
Methyl Alcohol (MeOH)
Xylene ((C6H4(CH3)2)
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 6.5 in
165.1 mm
Height 5.0 in
127 mm
Depth 7.0 in
177.8 mm
Weight 4.0 lb
1.8 kg
Enclosure Nema 4 Explosion Proof Suitable for Class 1, Group B, C, & D
Country of Origin USA
Harmonized Tariff Code 8531.10.0045

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 $2,795.00 US (P/N # 99058)
Horn and Strobe  $170.00 US (P/N # 42002)
Remote Display $395.00 US (P/N # 99091)

Self-Supervised Operation
The PureAire Air check Ex incorporates sophisticated electronics that, when used in conjunction with distributive control systems or PLCs 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 AirCheck Ex outputs a 0 mA signal to remote alarm/control systems to immediately alert control room personnel.

ST-46 EX-LEL Combustible Gas Monitor Literature

ST-46  EX-LEL Combustible Gas Monitor Manual  

How to Connect a Horn and Strobe to an LEL Monitor

LEL Combustibles Layout 

LEL Monitor Layout 

LEL Monitor with Fan Relay

 Gases Detected with PureAire Monitors