ST98B-AN Mass Flow Meter

Mass Flow Meter Summary

The ST98B-AN BASIC insertion type FlexMASSter sets a new standard for thermal mass flow meter performance, ease of use and installed value for Air or Nitrogen service. This field selectable insertion unit features an application-specific instrument package for fast ordering, simple installation and precision measurement. 

The ST98B-AN BASIC features FCI's popular ST98 Series innovative flow element design with leading-edge flow transmitter electronics and temperature compensation to ensure optimum performance in process temperatures that vary up to ± 100° F. It is available with all of the below listed standard features for a very attractive price and with quick delivery as soon as 5 business days ARO.


  • Monitoring air flow to burners
  • Aeration pond monitoring
  • Optimization of combustion air control systems


Flow Range: 1.25 to 125 sfps  [0.4 to 38 nmps] in Air or Nitrogen at standard conditions; 70° F [21.1° C] and 14.7 psia [1.01325 bar (a)].

Accuracy: (at calibrated conditions)  ± 1% reading + 0.5% full scale

Temperature Coefficient:
With optional temperature compensation. Valid from 10% to 100% of full-scale calibration
Flow: Maximum ± 0.015% of reading/ºF up to 850ºF [±0.03% of reading/ºC up to 454 ºC]

Repeatability: ± 0.5% reading

Turndown Ratio: Factory set at 100:1

Temperature Compensation: ± 30° F [± -1° C]

Temperature Range: 40° to 100° F  [4° to 38° C]

Pressure Range: 10 to 50 psia  [0.7 to 3.4 bar(a)]

Enclosure: Powder coated carbon steel rated for NEMA and CSA Type 4, water and dust tight 
(meets IP66).

Agency Approvals:  FM, CSA, CENELEC, ATEX and CE Mark.

N.I.S.T. Certified Test Lab Calibration: Standard

Flow Element

Materials of Construction: All welded 316L stainless steel for all wetted surfaces.

Process Connection: 0.75 inch male NPT stainless steel compression fitting with adjustable Teflon ferrule.

Insertion Length (Field Adjustable) 1:
  • 1 to 6 inches [25 to 152 mm]
  • 1 to 12 inches [25 to 305 mm]

Operating Temperature: Up to 200° F [93° C]

Operating Pressure: Up to 150 psig [10 bar(g)]

Note 1: After installation, stainless steel ferrule will be permanently fixed at the installed length.

Flow Transmitter

Operating Temperature: 0° to 140° F  [-18° to +60° C]

Input Power (Field Selectable) 2: 85 to 265 Vac or 22 to 30 Vdc; 16 watts maximum.

Output Signal (Field Selectable):
  • Current: 4 to 20 mA source; 800 ohms maximum load (with field selectable low [3.6 Ma] or high [21 mA] instrument fault indication; per NAMUR guideline NE 431).
  • Voltage: 0 to 5 Vdc, 1 to 5 Vdc or 0 to 10 Vdc; 100,000 ohms minimum load.

Digital Communication Port: RS-232C

Optional Display: 2 lines, 16 characters per line.  Indicates flow rate and process temperature or totalized flow (field selectable).

Optional Remote Configuration:
  • Flow Element Enclosure: Powder coated aluminum rated for NEMA Type 4X and hazardous locations Groups B, C, D, E, F and G, CENELEC EEx d IIC.

  • Flow Transmitter Enclosure: Powder coated carbon steel rated for NEMA and CSA Type 4, water and dust tight (equivalent to IP66).

Optional Interconnecting Cable: 25 ft. [7.6 m] PVC cable for remote configuration.

Optional Communicator/Programmer: FCI Model FC88 Hand-held plug-in interface.

Note 2: Output signal is isolated from input power on Vac powered units only.


  • ATEX
  • BelGIM (Products)
  • BelGIM (Pattern)
  • CCoE
  • CE
  • CPA
  • CRN
  • CSA
  • FM
  • EAC/TR CU (Russia)
  • IECEx
  • IECEx Test Report
  • HART