P/N 18545

Model 1500, Gaseous Flow Switch, 1/2" FNPT, 2.0-200 SCFM Increasing Flow, SPDT 20VA Pilot Duty, -14.7 to 1000 PSIG, -20°F to 225°F

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Product Information; Click to jump to Specifications

Description: This flow switch is an excellent choice for applications that may see high pressures as well as when flow set point adjustability is needed or desired. Having this adjustability is great for applications where you're not sure of the flow rate statistic, but know when the system is operating correctly. See our help page on flow switch adjustability for how this works.

Operation: Liquid flows through the housing, with flows below the "set point" the liquid flows around the piston and through the adjustable bypass channel, as the flow rate increases the piston with internal magnet starts to move backwards compressing the spring until the flow rate reaches the set point in which case the magnet actuates a hermetically sealed reed switch inside of another cavity of the flow switch. Flows above the set point pass by the piston and go through the bypass channel without issue holding the unit actuated until the flow rate begins to decrease where the spring begins to push the piston back down to resting position until the piston extends far enough away from the switch causing it to de-actuate. Flow rates below the set point do not effect the unit and do not cause it to actuate. Adjusting the flow set point is easy with a flat-head screwdriver, simply spin the vane to the desired location, the vane can spin around and around without stopping. When the slot on the vane is perpendicular to the inlet and outlet, the flow set point is at the lowest end of the range, and when the slot is parallel to the inlet and outlet, the flow set point is at the highest end of the range.

Common Applications: Some common places where you might see the model 1500 flow switch is in the Machine Tool industry, HVAC equipment.

Advantages Specialty Options
  1. Easy field-adjustable flow set points
  1. Strain reliefs are standard. Optional silicon potting available
  2. Optional 100VA SPST reed switches are stocked
  3. Relays for higher loads, junction boxes, terminal strips, etc. are available. See accessories section for details
  4. Optional cables/ cordsets available
  5. Optional SST identification tags attached to unit
  6. Optional M/S connector MS3102E10S-3P, Hirschmann or other connectors available
  7. Optional port sizes and process connections such as BSP, SAE, silver braze, socket-weld etc. are available
  8. High temperature units up to 400°F available
  9. Calibration in other substances or flow conditions are available
  10. Monel trim
  11. All metal such as SST or Brass shuttles instead of Teflon available
  12. Buna O-Rings instead of Viton
Special Notes

Product Specifications

Flow Switch 2000

Manufacturer :
Thomas Products LTD.
Model Number :
Model 1500
Type :
Gaseous Flow Switch
Special Features :
Mounting Type:
In-line/ Pipe Installation, Includes Dual 7/32" Mounting Holes For Flexible Tubing/ Solid Mounting
Housing :
Process Connection :
1/2" FNPT
UL Listed :
Flow Set Point :
2.0-200 SCFM Increasing Flow
Set Point Accuracy :
Not specified, unit is adjustable
Set Point Differential :
15% Max
Repeatability :
1% Max Deviation
Mounting Attitude :
Suggested: Ports horizontal, set point may slightly change otherwise
Reed Switch :
SPDT 20VA Pilot Duty
Reed Switch Logic :
SPDT, Black-Common, Red-NC, Orange-NO
Leads :
24" 18 AWG Polymeric
Wetted Materials :
Brass, SST, Viton "A", + Piston type chosen
Pressure Range :
-14.7 to 1000 PSIG
Proof Load :
2500 PSIG
Burst Strength :
5000 PSIG
Temperature Range :
-20°F to 225°F
"O" Ring :
Viton "A"
Spring :
Piston :
Variable, choose from dropdown
Check out these helpful videos for cleaning & general maintenance for some of our field serviceable products! https://www.youtube.com/playlist?list=PL_oLXohRDc29JLFLatP9Ainn_aF5FKeCL
Revision Level Changes Status
-NO Original release Current and active

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