FS10i Flow Switch + Monitor

Simple Universal Insertion Type Flow Switch  

The FS10i is a universal flow switch and flow monitor designed for simple insertion into ½” (13mm) or larger diameter pipes and square ducts. The unit is suitable for either liquid or air/gas applications. It is fast responding and highly repeatable to both increasing and decreasing flow rate changes. The standard 1A relay trip point is easily set in the field for low or high trip point and the trip and reset points can be further tuned with hysteresis and time delay adjustments. Also included standard is a 4- 20mA trending output of the flow rate for connection to ancillary controls or alarm systems. The FS10i includes a 10-LED array which provides both an indication the trip point has been exceeded (LED flashes on/off) and of relative flow rate (10% increments) across the flow range.

The FS10i provides best-in-class features for installation in rugged duty and long-life in industrial plants, process and large buildings. Its flow sensor’s thermowells are constructed of highly corrosion resistant Hastelloy C-22, it will operate in fluid temperatures up to 250°F/121°C, IP protection rating to IP67, optional global agency approvals for installation in Division 2/Zone 2 locations and it is the only unit in its price range to carry a SIL 2 compliance rating. It has no moving parts to clog and requires no routine maintenance which saves time and expense over any mechanical-technology based flow switch.


  • Cooling water and fluids
  • Lubricant flow assurance
  • Ventilation flow assurance
  • Relief valve monitoring
  • Nitrogen purge verification
  • Leak detection
  • Chemical injection
  • Filter blockage/change indication
  • Compressor operation assurance
  • Compressed air/gas leak alarm


  • Materials of Construction (Wetted Parts)
316L SS with Hastelloy C-22 thermowells
  • Flow Sensitivity/Setpoint Range
Water:    0.01 FPS to 0.5 FPS [0,003 MPS to 0,15 MPS]
Air/Gas: 0.25 FPS to 400 SFPS [0,076 MPS to 122 MPS]
  • Repeatability: ±0.5% of reading
  • Temperature Coefficient For temperatures > ±30°F [±16°C]
Gas: Maximum ±0.025% of reading/°F up to 250°F [±0,05% of reading/°C up to 121°C]
Liquid: Maximum ±0.2% of reading/°F up to 250°F [±0,367% of reading/°C up to 121°C]
  • Operating Temperature
-40°F to 250°F [-40°C to 121]
Teflon ferrule maximum temperature is 200°F [93°C]
  • Operating Pressure
2000 psi [138 bar]
Teflon ferrule maximum pressure is 150 psig [10 bar(g)]
  • Insertion “U” lengths
2″[50 mm] fixed
6″[150 mm] with variable insertion depth, compression fitting with Teflon or metal ferrule


  • Display
10 segment LED array, sequential lighting related to flow rate and flashing when trip point exceeded
  • Output Signals
Relay: SPDT, 1A @ 24 Vdc, 120 Vac Analog: 4-20 mA trending*
Serial: RS232C I/O
*500 ohm maximum load; user scalable, general purpose, uncalibrated output proportional to flow rate for trend monitoring or assignable to temperature; fault indication per NAMUR NE43 guidelines, user-selectable for high (>21.0mA) or low (<3.6mA) default
For linearized and calibrated analog outputs, see FCI’s line of thermal mass flow meter products
  • Operation
Two top-mounted buttons to program switch/trip point, zero and span setting, fail-safe, relay hysterisis and relay time delay; button operation may be user disabled to prevent unwanted changes; all set-up function are also user programmable via the RS232C serial port
  • Trip Point Hysteresis Control: 0-100% of span
  • Trip Point Time Delay: user settable for 0-65,000 seconds
  • Input Power
 24 Vdc (21.5 Vdc to 30Vdc); 2.5 watts maximum
  • Operating Temperature
 -40°C to 160°F [-40°C to 71°C]


  • Material: stainless steel body; aluminum end-cap/top with polyester overlay and clear, silicone sheath impact guard
  • Protection Rating:
Non-Ex Installations:      IP65 IP66, IP67
FM, FMc approved:         NEMA 4X
ATEX, IECEx approved:   IP64

Agency Approvals

  • FM, FMc:  Nonincendive, Class I, Division 2, Groups A,B,C,D; Class II, Division 2, Groups E,F,G; Class III, T4@Ta=71°C, Type 4X
  • ATEX, IECEx:  Nonincendive for gas and dust, Zone 2; II 3 G Ex ec IIC T4 Gc;  II 3 D Ex tc IIIC T81°C Dc; IP64
  • EAC/TR CU:  Pending. Contact FCI
  • Other CE Mark, CRN, complies with Canadian electrical code requirement of ANSI/ISA 12.27.01-2011 as single seal device.
  • IEC 61508 (SIL):  SIL 2 Compliant, SFF 90%


  • ATEX
  • CE
  • CRN
  • FMc
  • FM
  • EAC/TR CU (Russia) *pending
  • IECEx
  • SIL