Paddle flow switches, micro-switch contact, 3/4” BSPP union nut


Main uses: Water flow detection on water pipes

Functional principle: Balanced paddle, perpendicular to the main flow, actuating a micro- switch. Flexible elastomeric gasket between

paddle and electric switch

Weight N/A
Flow sensing

Main housing material

Paddle material


Electrical rating

Ingress protection

Maximum flow detection (L/min)

Minimum flow detection (L/min)

Nominal pressure at 20°C

Max operating temperature (°C)

Liquids temperature range (°C)


Size and pressure Flow sensing:

Cleavable paddle


¾” BSPP Union nut



Electrical rating Mounting position Type




Type A Standard cleavable paddle

1: Paddle

2: Body

3: Cable

Type B Paddle for DN15 tee


1: Paddle

2: Body

3: Cable

Main uses: Water flow detection on water pipes

Functional principle: Balanced paddle, perpendicular to the main flow, actuating a micro- switch. Flexible elastomeric gasket between

paddle and electric switch

Main housing material: PPO, fiber glass reinforced, usable with potable water.

Paddle material: Polypropylene, resistant to ozone and water disinfection products

Paddle gasket: Santoprene, resistant to ozone and water disinfection products

Electrical rating: 5A resistive, 230V AC

Electric contact type: SPDT, open or close by flow rise

Liquids compatibility: For use with clean water and liquids without chemical incompatibility with PPO and Santoprene

Nominal pressure at 20°C: 1MPa (PN10)


Assembly on pipes with ¾” union nut:

Assembly on pipes with snap-in fitting:


Average Flow detection values vs pipe I.D. and paddle length (Liters/min)


Paddle length

Pipe ID (mm)***

15*** 20 25 32 40 50 63
*Close **Open *Close **Open *Close **Open *Close **Open *Close **Open *Close **Open *Close **Open
1 8.3 7,2 16,3 11,6 37 36 77 68 157 128 260 202 598 412
1+2 24 18 53 50 108 97 183 160 421 327
1+2+3 43 38 88 82 168 140 386 286
1+2+3+4 70 68 130 118 299 241
1~5 52 50 110 98 253 200
1~6 90 88 217 170
1~7 78 77 178 158
1~8 150 135
1~9 135 122
* Close by flow rise (L/min) of contact open at no flow position

** Open by flow decrease (L/min) of contact open at no flow position. Average values for indication only. Standard tolerances ±30%

*** With3/4 DN15 brass tee (see accessories) and type B non cleavable paddle

Nominal diameter: Can be used on 20 to 63 mm internal diameter pipes The paddle is cleavable and can be cut at various lengths upon pipe diameter. There are cutting lines numbered 1 to 9 every 5mm.

Recommended mounting position: Vertical, with paddle downside. Other positions are possible with a change in the calibration value related to the paddle weight. .

Water pipe connection: Supplied with a fiber glass reinforced PA66G3/4”(BSPP) union nut and NBR gasket. Must be used on a BSPP3/4 male fitting perpendicular to the main pipe.

Recommended torque: 7Nm. Version for snap-in mounting (see accessories) has no nut

Liquids temperature range: 5 to 80°C

Ambient temperature range: 5 to 50°C

Ingress protection: IP65

Electrical connection: 3 x 0.75 mm² cable, PVC insulation, T80°, style H05VVF.

Installation instructions:

  • Check carefully the paddle orientation: The arrow on housing must be exactly parallel to the pipe
  • A 5 mm minimum gap must be respected between end of the paddle and tube wall opposite to the 3/4”
  • We recommend the use of nozzles of length less than or equal to 18mm between the gasket seat and the inside of the tube and with an inner diameter greater than or equal to 14mm, to avoid blocking of the

Accessories: 3/4” PVC saddles forDN40 to DN100 (OD) PVC pipes, and other fittings: see last section of this catalogue


  • Cable with connector or terminals, other cable length, nickel plated brass


Main references

Technical specifications sheet



Technical informations associated to this product

  • Flow switches historical foreword

    In antiquity, the flow measurement was one of the first means of time measurement. But it was not until the steam engines development and the need to control their water supply, that measuring devices were developed.
  • Flow switches technical foreword

    A certain force is required to actuate the electrical contact device. It can range from a few tenths of grams for systems with reed contacts with a power rating of 10 to 20VA (0.5Amp), to 50 grams for snap action micro-switches with a 5Amp 250V rating
  • Electrical contacts

    As numerous mechanisms exist, we decided not to distinguish on the basis of constructive technique, but according to their operation speed, which is the key element.