Target: Refrigerant,R32,R454B,R410A,R134A
Model: MH-441D
Detection range: 0~5%VOL
Detection principle: NDIR
Characteristics: High sensitivity, high resolution, fast response,Output method: UART, analog voltage signal
Size: Φ20×22.4mm
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MH-440D infrared gas sensor is a miniature universal intelligent sensor, which adopts NDIR theory to detect concentration of CH4 in air and has good selectivity, stable performance, long life, also is independent of Oxygen. The inside temperature sensor could be used for temperature compensation. This miniature infrared gas sensor is developed by the tight integration of mature infrared absorbing gas detection technology, micro machine workout and superior circuit design.
It is convenient in use and also instead of catalytic component directly, widely used in various occasions with flammable and explosion hazard gas.


Widely used for HVAC refrigeration, air monitoring indoor, industrial-process control and safety protection, agriculture and animal husbandry.


  • High sensitivity, high resolution, fast response
  • Output method: UART, analog voltage signal
  • Temperature compensation, excellent linear output
  • Excellent stability, Long lifespan
  • Anti-poisons, anti-vapor interference
  • Can replace catalytic type gas sensor directly


Fig1.Technical Parameters

Part Number MH-441D
Detection Gas Refrigerant
Detection Range 0~5%VOL
WorkingVoltage 3.6~5VDC (Reuqire powered by safety barrier)
Average Current <85mA
Interface Level 3.0V
OutputSignal UART(3.0V)
0.4~2.0VDC(Requireoutput by safety barrier)
Warm-up time 3 min
Response time T90<30 seconds
WorkingTemperature -20°C ~ 60°C
WorkingHumidity 0~95%RH(no condensation)
Sizes Φ20×22.4mm
Weight 35g
Lifetime >5 years
Defense Grade IP54
Power, communication terminal Intrinsic safety Ui=7.5VDC,Ii=265mA, Pi=0.5W,Ci=10μF,Li=0mH


Fig2.Measuring Range andRefrigerant conversion factor

Target Gas Molecular Formula MeasuringRange Resolution No. of decimal Accuracy Relative coefficient
R32 CH2F2 0~5.00% Vol 0.01% Vol 2 ±5%F.S(0.00%-1.00%) 1
454B CH2F2(68.9%) 0~5.00% Vol 0.01% Vol ±5%F.S(0.00%-1.00%) 0.91
C3H2F4(31.1%) ±10%F.S(1.00%-5.00%)
R410A CH2F2(50%) 0~5.00% Vol 0.01% Vol 2 ±5%F.S(0.00%-1.00%) 0.81
C2HF5(50%) ±10%F.S(1.00%-5.00%)
R134A C2H2F4 0~5.00% Vol 0.01% Vol 2 ±5%F.S(0.00%-1.00%) 0.28

* The description and specifications might be changed without notice. Please contact us for the latest information before placing orders.

Technical Support:

Customized technical design and function, LOGO and package are available without extra charge (including molding fee) for mass volume.

The sensors don't have sleeping mode. It can be set in program if needed.

All Winsen products go through strict inspections and tests to make sure they are 100% qualified before shipping out.

The sensor has been fully tested (not calibrated) before leaving the factory. However, after transportation and storage, the environment conditions change, and the surface of the sensor absorbs moisture, mixed gas, pollution matters, etc. It is recommended that customers perform aging and calibration after sensors become stable according to the program and use occasions of the whole device.

15﹪-90﹪RH without condensation,greater or less than this range or long-term high temperature and high humidity will affect the life of the sensor.

Our sensors are certified with UL, CE, 3C, ROHS, anti-explosion, fire prevention, and coal mining safety according to different applications. And we provide assistance for new certification.

Many factors can cause the sensor to fail such as broken wires in transportation, poisoning, falling off of the sensitive material, damage to the heating wire (device), etc. Please find specific cause in each category with Winsen’s aftersales.

Winsen provides professional consultation and service before and after sales. We will recommend the best fitting sensor for your demand. If you have any problem, don’t hesitate to email us to

Due to high volume of daily incoming emails and time zone difference, we may not be able to reply your emails immediately. But we will reply to your inquiry in 24 business hours.