Paddle Series V4

Product Applications

  • Protects pumps, motors and other equipment against low or no flow
  • Controls sequential operation of pumps
  • Automatically starts auxiliary pumps and engines
  • Stops liquid cooled engines, machines and processing when coolant flow is interrupted
  • Shuts down burner when air flow through heating coil fails
  • Controls dampers according to flow


The Series V4  Flow Switches are rugged and reliable, ideal for automatically protecting equipment and pipeline systems against damage from reduction or loss of flow. Time tested in thousands of pipeline installations and processing plants around the world this Series is Weatherproof, designed to meet NEMA 4 and Explosion-proof (listing included in specifications). This series can be used in pipes 1-1/2″ (38.10 mm) and up.


ServiceGases or liquids compatible with wetted materials.
Wetted MaterialsVane: 316 SS; Body: Brass or 316 SS standard; Magnet Keeper: 430 SS standard, 316 SS optional; Options: Other materials also available, consult factory (e.g. PVC, Hastelloy, Nickel, Monel, Titanium).
Temperature Limit-4 to 275°F (-20 to 135°C) standard, MT high temperature option 400°F (205°C) [MT option not UL, CSA, ATEX or IECEx] ATEX and IECEx options, ambient temperature -4 to 163°F (-20 to 73°C); Process temperature -4 to 163°F (-20 to 73°C).
Pressure LimitBrass body 1000 psig (69 bar), 316 SS body 2000 psig (138 bar), optional 5000 psig (345 bar) available with 316 SS body and SPDT switch only.
Enclosure RatingWeatherproof and Explosion-proof. **Listed with UL and CSA for Class I, Groups C and D; Class II, Groups E, F, and G. ATEX CE 2813 EX II 2 G Ex db IB T6 Gb -20°C≤Tamb≤73°C. -20°C≤Process Temp≤73°C. EU-Type Certificate No.: KEMA 03 ATEX 2383. ATEX Standards: EN 60079-0:2012+A11:2013;EN 60079-1:2014.
IECEx Certified: For Ex db IB T6 Gb – 20°C≤Tamb≤73°C. -20°C≤Process Temp≤73°C. IECEx Certificate of Conformity: IECEx DEK 11.0071. IECEx Standards: IEC 60079-0: 2011; IEC 60079-1: 2014. Zone I. Also FM approved.
Switch TypeSPDT snap switch standard, DPDT snap switch optional.
Electrical RatingUL, FM, ATEX and IECEx models 10 A @ 125/250 VAC. CSA models: 5 A @ 125/250 VAC; 5 A res., 3 A ind. @ 30 VDC . MV option: 1 A @125 VAC; 1 A res., .5 A ind. @ 30 VDC. MT option: 5 A @ 125/250 VAC. [MT and MV option not UL, CSA, FM or ATEX or IECEx].
Electrical ConnectionsUL and CSA models: 16 AWG, 6″ (152 mm) long. ATEX and IECEx unit: Terminal block.
Conduit Connection3/4″ female NPT or 19.05 mm standard or M25 with -BSPT option.
Process Connection1-1/2″ male NPT or 1-1/2″ male BSPT or 38.10 mm.
Mounting OrientationWithin 5° of vertical for proper operation. Units for horizontal installation (vertical pipe with up flow) available.
Set Point AdjustmentFor universal vane: five vane combinations.
Weight4 lb 8 oz (1.9 kg).
Agency ApprovalsATEX, CE, CSA, FM, IECEx, UL**.


  • Leak proof body machined from bar stock
  • Choice of custom vane calibrated for your application, Model V4, or field adjustable multilayer vane, Model V4-2-U (see set point chart)
  • Installs directly and easily into pipeline with a threadolet, tee, or flange (see application drawings)
  • Can be used in pipes 1-1/2″ and up
  • Electrical assembly can be easily replaced without removing the unit from installation so that the process does not have to be shut down
  • High pressure rating of 1000 psig (69 bar) with the brass body and 2000 psig (138 bar) with the 316 SS body
  • Unique magnetically actuated switching design gives superior performance
  • Features a free-swinging vane which attracts a magnet within the solid metal switch body, actuating a snap switch by means of a simple lever arm with no bellows, springs, or seals to fail