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Thermal Flow Switches

FSW-420 & FSW-430 Series

Thermal Flow Switches | FSW-420 & FSW-430 Series

Thermal Flow Switches

$450.00 FSW-433

1 year warranty CE
  • Automatic Scaling and Set-Point
  • No Moving Parts
  • Pushbutton Re-Scaling if Needed
  • Easy to Install
  • Normally Open Standard, Normally Closed Available
Variable Area Flowmeters, Rotameters & Switches - View related products


The FSW-420/30 Series monitors your relative flow rate for applications where the actual flow rate is not important. The FSW-420/30 series is easy to install and use. Just put it into the pipe and it’s ready to go. The FSW-420/30 series sets your present flow-rate at 100% at power up. Relative flow rate is indicated by the 7 LED lights. When the flow rate drops to 50%, an alarm goes off. If you prefer, you can adjust the alarm point to fit your needs. A green output indicating LED is also included.

Media: Liquids
Low Flow Set Point: Pre-set to 50% (field adjustable)
Operating Temperature: -20 to 80°C (-4 to 176°F)
Response Time: 25 seconds (typical)
Repeatability: 1%
Hysteresis: 10% of set-point value typical
    FSW-420 Series: 0 to 150 cm/sec
    FSW-431: 0 to 2.25 L/min
    FSW-432: 0 to 5.1 L/min
    FSW-433: 0 to 14.1 L/min
Operating Pressure: 30 Bar (450 psi)
Protection Class: NEMA 6 (IP67)
Housing: Anodized aluminum
Sensor Material: 303 stainless steel
Tube Housing (FSW-430 series): Polyacetal
Mounting (FSW-420 Series): ½ NPT
Connection Tube OD:
    FSW-431: 6 mm (0.24")
    FSW-432: 8 mm (0.31")
    FSW-433: 12 mm (0.47")
Electrical Connection: M12 male socket 4-pin, 2 m (7') cable with M12 connector and pigtail leads
Supply Voltage: 20 to 30 Vdc (short circuit protected)
Switching Current: <200 mA
Power Consumption: 6 W max
Initial Operation: 15 seconds
Output: PNP normally open (closed with flow), optional normally closed (open with flow)
Place Order(Specify Model Number)

What Other People Bought: When you see this icon, click on it to expand a list of products that other people have bought when they purchased this model.

Part Number/Desc.
Normally Open Flow Switch
Availability: In Stock  
Insertion flow switch, 12.5 mm (0.5") insertion length
Availability: In Stock  
In-line flow switch 12 mm (0.47") tube
Availability: In Stock  
FSW-400 Series connection cable 2m (7')
Click to expand/minimize a list of what others bought with the70A-1
Availability: In Stock  
audible alarm
Click to expand/minimize a list of what others bought with thePSU-93
Availability: In Stock  
power supply
All amounts shown in USD
Note: Comes complete with operator's manual and pre-wired 2m(6/5') cable.

Standard valves are Normally Open. For optional Normally Closed valves, add "-NC" to model number, no additional charge.

Ordering Example: (1) 70A-1 Audible alarm, $25.00   plus (1) PSU-93 Power supply, $49.00, $25.00 + 49.00 = $74.00