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MF420 200x200
  • CH4
  • CHx
  • LPG
  • Rx


The measuring systems of the product family MF420-C, with a semiconductor sensor, determine the concentration of explosive gases and vapors in air mixtures. The concentration is given out via a 4 - 20 mA interface for further processing. The sensor is characterized by its robustness towards sensor poisons and its long life cycle. The measuring range is 0 - 50% LEL.

In combination with our limit monitors (GWZ) gas measurement systems for detection of explosive gases and vapors in ambient air, like eg. storage facilities, can be set up.

Measuring Ranges

The measuring ranges depend on the measured gas or vapor. For a table of ranges please refer to the product assortment. Other gases, vapors, and concentrations are also possible on request.


The device complies with the generic standards EN 61000-6-2 and EN 61000-6-3 and thus the EMC Directive 2004/108/EC.

Maintenance and Service

The device is delivered already calibrated. The maintenance cycle must / should correspond to the given safety requirements. We recommend at least a semi-annual inspection of the equipment by qualified personnel. You can also use our service.

For more details, please refer to the technical data or ask our contact person.

Product NameProduct FeaturesProduct Code
MF420-H Methane
Measuring Range 0 - 50% LEL
MF420-H Propane
Measuring Range 0 - 50% LEL
MF420-H Butane
Measuring Range 0 - 50% LEL
Measuring Range 0 - 50% LEL
MF420-H R134a
Measuring Range 0 - 1000 ppm
MF420-H R404a
Measuring Range 0 - 1000 ppm
MF420-H R410a
Measuring Range 0 - 1000 ppm

Other gases & vapors on request.

Principle of Measurement semiconductor  
Power Supply voltage 24 V DC ± 5%
current approx. 100 mA
connectors 3-pole screw terminal 24 V DC ±5% and 4..20 mA
Ambient temperature -10°C to +50°C  
Air pressure 900 hPa to 1100 hPa  
Permissible Humidity 15 to 95% relative humidity non condensing
Output 4 - 20 mA  
Housing Alloy, red  
Protection class IP 54
Weight approx. 500 g
Dimensions (L x W x H) 90 x 85 x 65 mm
Connecting Cable 3-wire shielded cable Recommended cable cross-section min. 1.5 mm2

Pin Assignment:

Product NameProduct FeaturesProduct Code
Replacement Sensor Set Consists of:
- Replacement sensor
- Sensor holder
- Sinter
- Seal
on request
Calibration Set Consists of:
- Test gas cap
- O-ring
on request