FLT93L Flow Switch

FCI Model FLT93 with yellow enclosure and stainless steel tube tee flow element

Flow Switch Summary

The FLT93L inline type FlexSwitch for flow and temperature monitoring represents the first true technological breakthrough in thermal technology in over a decade. FCI is the only thermal manufacturer providing temperature compensation to ensure set point accuracy for process temperatures that vary up to ± 100°F. The FLT93L is easily field-configured or factory preset, providing unparalleled flexibility, accuracy and stability for all multiple process sensing and switching requirements.


  • Pump protection
  • Cooling water/heat exchangers
  • Drain line flow
  • Safety spray nozzle monitoring
  • Oil well system testing
  • Relief valve monitoring


For Flow Service - Setpoint Range:
  • Water-based Liquids:
0.015 to 50 cc/sec [0.0009 to 3 lps]
  • Hydrocarbon-based Liquids:
0.033 to 110 cc/sec [0.002 to 6.6 lps]
  • Air/Gas:
0.6 to 20,000 cc/sec [0.036 to 1198 lps]

Accuracy: (whichever reading is higher)
  • Liquids: ± 0.5% reading or ± 0.04 fps [± 0.012 mps]
  • Gases: ± 0.5% reading or ± 2 sfps [± 0.06 nmps]

For Temperature Service:
  • Accuracy: ± 2° F [±1° C]
  • Repeatability: ± 1° F [± 0.6° C]

Response Time: As low as 0.5 seconds.

Enclosure: NEMA 4X/IP66 Rated. Standard: Polyester power coated aluminum, with single 1" NPT conduit port. Optional: Stainless steel. Optional: Dual-conduit port, aluminum with 1/2" NPT or M20 metric conduit ports.

Compliances and Agency Approvals: FM, FMc, ATEX, IECEx, EAC/TR CU, Inmetro. CE mark. PED, CRN.
Meets EC directives for EMC and LVD. Probe complies with Canadian Electrical code requirements of ANSI/ISA 12.27.01-2011 as a single seal device.
  XP, Class 1, Div. 1 Groups B,C,D, T3A or T4 Ta ≤60°C
DIP, Class II/III, Div. 1, Groups E,F,G, T3A or T4 Ta ≤60°C
Nonincendive for Class I, II and III, Division 2, Groups A,B,C,D,E,F, and G, T3A or T4 -40°C ≤Ta≤60°C; hazardous (classified) locations, indoors and outdoors.
Type 4X
ATEX: Integral:                        II 2 G  Ex db IIC T4…T2 Gb
                                     II 2 D  Ex tb IIIC T135°C…T300°C Db
  Remote enclosure
  + electronics:             II 2 G  Ex db IIC T6 Gb
                                     II 2 D  Ex tb IIIC T85°C Db
  Local enclosure
  + sensor                     II 2 G  Ex db IIC T4…T1 Gb
                                     II 2 D  Ex tb IIIC T135°C…T345°C Db
  Pigtail version            II 2 G  Ex db IIC T4…T3 Gb
                                     II 2 D  Ex tb IIIC T135°C…T200°C Db
IECEx: Integral:                        Ex db IIC T4…T2 Gb
                                     Ex tb IIIC T135°C…T300°C Db
  Remote enclosure
  + electronics:             Ex db IIC T6 Gb
                                     Ex tb IIIC T85°C Db
  Local enclosure
  + sensor                     Ex db IIC T4…T1 Gb
                                     Ex tb IIIC T135°C…T345°C Db
  Pigtail version            Ex db IIC T4…T3 Gb
                                     Ex tb IIIC T135°C…T200°C Db
Optional N.I.S.T. Flow Calibration Services
Factory N.I.S.T. calibration in air or water is available as an option for customer specified setpoint(s) or a flow curve based on the media ranges specified above.

Flow Element

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

Process Connection: 
  • Standard: 1 inch male NPT or 0.75 inch female NPT at tee inlet and outlet
  • Optional: Flanges
Inline Tee Length: 3.375 inch [86 mm]

Operating Temperature: 
  • Standard: -40° to +350° F [-40° to +177° C]
  • Optional: -100° to +500° F  [-73° to +260° C]

  • Operating Pressure: To 3500 psig [240 bar(g)]

Control Circuit

Operating Temperature: -40° to +140° F [-40° to +60° C]

Universal AC/DC supply. Input terminals and jumpers on circut board select specific power.
AC 108-132V 13W, 100mA max.
AC 207-253V* 14W, 50mA max.
AC 18-28V 7W, 230mA max.
DC 21-30V 7W, 230mA max.
* AC mains preset by factory: FM & FMc as 108-132 Vac; All others as 207-240 Vac 

Relay Contacts: Field configurable dual SPDT or single DPDT rated 6 amps at 115 Vac, 240 Vac or 24 Vdc. Hermetically sealed relays are available as an option.

Output Signal: Analog DC voltage related to flow or level/interface signal and proportional to temperature.

Electrical Connection: 1 inch female NPT 

Remote Configuration: Available as an option with customer specified interconnecting cable length.