CalFlo™ CFNF2 DC Thermal Mass Air, Flocorp-Flow Switch

CalFlo™ CFNF2 DC Thermal Mass Air Flow Switch

The CalFlo series of calorimetric flow switches offer units with several features including temperature & flow, compact relay control, strobe alert, adjustable flow, compact airflow, inline airflow, and more. The wide variety of options available enable us to provide the right unit for your specific application. If you need help selecting the correct flow switch, our team is happy to assist in the selection process.

This industrial purpose flow switch is a great choice for monitoring a variety of air or gaseous applications. The CalFlo™ CFNF2 features solid-state switching and is extremely reliable even under the harshest environmental conditions. NitroFlo features a repeatable alarm, an adjustable set-point from 3 to 32 feet per second, and an LED indication of flow. The short housing is intended for use in pipe sizes ½” to 1 ½” in diameter and the long housing is recommended for pipe sizes 2” and up. Typical applications include air conditioning, ventilation, air filter monitoring, extraction fans, blowers, damper regulators, and energy conservation systems.

Features and Benefits

  • Compact flow switch with rugged Stainless Steel or plastic Ultradur construction
  • High accuracy with NO moving parts
  • 24 VDC power supply
  • Set-point adjustable between 3 fps and 32 fps
  • Temperature independent
  • Easy installation with mounting flange (included)


ServiceCompatible Gasses
Switching Range3 to 32 fps (1 to 10 mps)
Factory set-point10 fps (3 mps)

CFNF2-U: 15 psi (1 bar)

CFNF2-S: 150 psi (10 bar)

Hysteresis≤ 30%


Switching Delay

Min. 3 s/ Max. 100 s (depends on set- point adjustment)
Temperature Drift< 0.5% / K
Supply Voltage24 VDC ±10%
Residual Ripple20%
Switching Current500 mA max.
Repeatability< 3%
ConsumptionApprox. 1W
Starting Override Time


Max. 90 s




PNP Normally Open (closed with flow) PNP Normally Closed (open with flow) NPN Normally Open (closed with flow) NPN Normally Closed (open with flow)
DisplayLED for ON or OFF state
Process Temp.F: -4º to 160º C: -20º to 70º
Ambient Temp.F: -4º to 160º C: -20º to 70º
Enclosure RatingNEMA 4 (IP64)
Housing MaterialUltradur (PBTP) or Stainless Steel
Sensor MaterialCeramic with Over Glaze

CFNF2-U: 0.3 lbs (130 g)

CFNF2-S: 0.4 lbs (200 g) without nut

Cable Jacket Material



Cable Length6.5’ (2m)

Download Datasheet: CalFlo™ CFNF2 DC Thermal Mass Air Flow Switch