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Flow Switch FH12B04-M12 ideal for medium flows of oil - 1/2"G

Eicos flow switch FH12B04-M12, ideal for medium liquid flows

1 pc.

168.00 € pc.
In stock
CONTACT   min. 50%*
1.5 8.0
1.0 6.0
CONTACT   min. 50%*
0.40 5.00
0.05 4.00

*Half-scale reference.



The fluid flow causes the displacement of magnetic piston and closes the electrical contact of sensor (reed switch).

The Eicos flow switch FH12B04-M12 of 1/2"G port is ideal for medium flows of oils. The sensor has an operation range that allows to adjust the ideal flow of liquid to be detected in application.

The sensor works Normally Open (NO), with ON signal when the flow (liters per minute) is higher that the sensitivity adjusted in the sensor and OFF signal when the flow decreases below the set point.

Output connection in male M12 plug (not included with sensor).

For water applications, see the model FH12B02-M12.

Advertência 2

Liquids with magnetic particles will cause deposition/magnetic sedimentation and it will prejudice the operation of the sensor. Use magnetic filter before the sensor.

Liquids with encrustation particles and/or solids require tests.

Technical specifications

BodyPPA - Polyphthalamide
Internal clearance 114mm²
Maximum operation pressure 25bar
Operating temperature range 0ºC to 100ºC | 140ºC @1h
Inlet/outlet port G 1/2" female (BSP - Parallel)
Spring AISI 302 stainless steel
Sealing NBR (nitrilic rubber) O'Ring
Output connection M12 male, 2 pins (A-code)
Enclosure rating IP66
Electrical contact Reed Switch 20W/VA
Warranty 2 years

Switching Voltages

Operating Voltage Max. switching power Max. switching current
110Vac 20VA 0.2A
220Vac 20VA 0.1A
5Vdc 2.5W 0.5A
12Vdc 5W 0.5A
24Vdc 10W 0.5A
  • 24Vac: Use with Schneider relay coupler model RSLZVA1 or equivalent.
  • Relay coupler (110Vac-220Vac): Use 4K7 10W resistor in series.


Beware of EXCESSIVE force to which the sensor will be submitted in its installation.
FLOW Montagem correta

Dimensions (mm) and weight

Sensitivity adjustment 200g Scale   Inlet fittin Outlet fittin dimensões


O'Ring (NBR) for sealing
Parker code 2-116

Typical connection to contactor and electrical connection

AUXILIARY CONTACTOR (mini contactor)
Check the distance:
Direct connection
to the sensor
Use 22R 5W
in series
24Vdc voltage
Distância ligação
Esquema ligação contator

Installing the snubber filter extends the lifespan of the sensor’s electrical contact.

Never connect the sensor directly to a motor, pump, lamp or any other load over 20W.
Always use a contactor or relay.
M12 male connector 2 pins M12 female connector Flow Switch 1-BR 3-BL Esquema Plug M12
SwitchNO - SPST
OutputContact ON/OFF
Enclosure ratingIP66


  1. Open the plug, remove the spring and clean using a nylon brush if there is encrustation;
  2. Mount the sensor again as illustrated bellow:
Plug O'Ring Spring Piston Allen Wrench 12mm Scale Brush M12 conector Manutenção


1) The electrical contact keep on closed WITHOUT flow.
  • Check if there si overload;
  • Test with an ohmmeter;
  • Open the plug and check if the piston is not blocked.
2) There is flow and the electrical contact remains always open.
  • Adjust the sensitivity;
  • Check the electrical contact with an ohmmeter;
  • Possible overload that damaged the electrical contact.

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