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Dwyer Series GFM4

Series GFM4 Gas Mass Flow Meter

Pressure, Temperature and Flow Monitoring

Dwyer Series GFM4
Series GFM4

The Dwyer Series GFM4 Gas Mass Flow Meter is an ideal choice for the measurement of flow rates of a wide variety of gases. This multi parameter flow meter supports various functions such as flow totalizer, flow, temperature, and pressure alarms, and is available in a choice of 0 to 5VDC, 0 to 10VDC, or 4 to 20 mA output signals. Standard LCD and four button keypad allows easy access to the many features of the GFM4. Digital interface operates through available RS-485 or RS-232, providing access to internal data parameters and multi-drop capability of up to 255 units (RS-485 only). Set alarms remotely via digital interface for flow, pressure, and temperature to alert user of high or low thresholds being exceeded. With a high ±1% FS accuracy and ±0.25% FS repeatability, the GFM4 is the optimal choice in gas flow metering and monitoring. The GFM4 comes with a NIST traceable certificate.


Dwyer Series GFM3 Specifications

  • Service:Clean gases compatible with wetted parts.
  • Wetted Materials:316 SS, 416 SS; Fluoroelastomer, Buna-N, EPR or PTFE O-rings.
  • Accuracy:±1% FS.
  • Repeatability:±0.25% FS.
  • Response Time:0.6 to 1.0 s to within ±2% of setpoint over 20 to 100% FS.
  • Output Signal:Linear 0 to 5 VDC (3000 Ω min. load impedance); 0 to 10 VDC (6000 Ω min. load impedance); 4 to 20 mA (500 Ω max. loop resistance).
  • Relay Rating:1 amp @ 24 VDC.
  • Max. Particulate Size:5 microns.
  • Temperature Limits:Ambient: 32 to 122°F (0 to 50°C); Dry Gases: 14 to 122°F (-10 to 50°C).
  • Power Supply:12 VDC; 15 VDC; ±24 VDC.
  • Process Connections:1/8″ compression fitting for flow rates ≤ 10 L/min; 1/4″ for ≤ 50 L/min; 3/8″ for ≤ 100 L/min.
  • Pressure Limits:500 psia (35 bar).
  • Leak Integrity:1 x 10-9 smL/sec of helium.
  • Display:128 x 64 graphic LCD with backlight.
  • Weight:1 lb (.45 kg).



  • Multi-drop capability of up to 256 units (for RS-485 option).
  • Programmable 12 digit totalizer indicates total gas volume.
  • Flow alarm limits for high and low gas flow with relay output.
  • Pressure alarm limits for high and low gas pressure with relay output.
  • Four button keypad and large 128×64 graphical LCD with backlight.
  • Internal conversion factors for up to 32 gases.
  • Automatic zero adjustment.
  • Self diagnostic tests.
  • Free communication software available.



  • Model A-110N12 110 VAC Power Supply, 12 VDC Standard Interface
  • Model A-110N24 110 VAC Power Supply, 24 VDC Standard Interface
  • Model A-110NA15 110 VAC Power Supply, 15 VDC Standard Interface