Wilo-Sub TWI 4

Series description


Multistage 4" submersible pump in tie strap version for vertical or horizontal installation


  • For water and drinking water supply from boreholes and rainwater storage
  • Process water supply
  • For municipal water supply, sprinkling and irrigation
  • Pressure boosting
  • Lowering the water level
  • For pumping water in industrial applications
  • For pumping water without long-fibre and abrasive constituents

Type key

E.g.Wilo-Sub TWI 4.01-09-CI
TWISubmersible pump
4Diameter of the hydraulic unit in inches ["]
01Rated volume flow [m3/h]
09Number of hydraulic stages
CSeries generation
IMotor shroud in 1.4571, motor connection via flat motor socket

Special features/product advantages

  • Long service life thanks to corrosion-resistant stainless steel, optionally in V4A quality
  • ACS certified for drinking water applications
  • A high degree of flexibility thanks to versions in the 4, 6, 8 and 10-inch area
  • High range of performance from 1 to 250 m³/h


  • Multistage submersible-motor pump with radial impellers
  • Integrated non-return valve
  • NEMA coupling
  • Single-phase or three-phase motor
  • Hermetically cast motors

Technical data

  • Minimum Efficiency Index (MEI) to ≥ 0.7
  • Mains connection: 1~230 V, 50 Hz or 3~400 V, 50 Hz
  • Submerged operating mode: S1
  • Fluid temperature: 3 – 30 °C
  • Minimum flow rate at motor: 0.1 m/s
  • Max. sand content: 50 g/m3
  • Max. number of starts: 20/h
  • Max. immersion depth: 150 m
  • Protection class: IP68
  • Pressure connection: Rp 1¼ – Rp 2


  • Hydraulic housing: 1.4301 stainless steel
  • Impellers: 1.4301 stainless steel
  • Hydraulics shaft: 1.4057 stainless steel
  • Motor housing: 1.4301 stainless steel
  • Motor shaft: 1.4305 stainless steel


Submersible pump with ACS approval for vertical or horizontal installation.


Multistage submersible-motor pump with 4" NEMA connection and radial or semi-axial impellers with sectional construction. Integrated non-return valve. All parts that come in contact with the fluid are made of corrosion-free materials.


Corrosion-free single-phase or three-phase motor for direct starting. Sealed and hermetically cast motor, resin-impregnated, with enamel-insulated winding, self-lubricating bearing, with water-glycol filling.


The motor is cooled by the pumped fluid. The motor must always be immersed when operated. The limit values for maximum fluid temperature and minimum flow velocity must be adhered to. Vertical installation is possible with or without cooling jacket. Horizontal installation must be performed in conjunction with a cooling jacket.

Pressure shroud

The pressure shroud is used for the direct installation of the unit in the pipe network. Standard models are without mounted non-return valves. The maximum inlet pressure is 10 bar.


  • No suction mode is possible with these units!
  • The unit must be fully immersed in water during operation.

Scope of delivery

  • Hydraulics + motor fully assembled
  • 1.5/2.5 m connecting cable approved for drinking water (cross-section: 4x1.5 mm2)
  • Single-phase version including switchbox with capacitor, thermal motor protection and On/Off switch
  • Installation and operating instructions


  • Hydraulics in stainless steel 1.4401
  • Motor in stainless steel 1.4401
  • 60 Hz version

General notes - ErP (ecological design-) directive

The benchmark for most efficient water pumps is MEI ≥ 0.70The efficiency of a pump with a trimmed impeller is usually lower than that of a pump with the full impeller diameter. The trimming of the impeller will adapt the pump to a fixed duty point, leading to reduced energy consumption. The minimum efficiency index (MEI) is based on the full impeller diameter.The operation of this water pump with variable duty points may be more efficient and economic when controlled, for example, by the use of a variable speed drive that matches the pump duty to the system.Information on benchmark efficiency is available at www.europump.org/efficiencycharts

Duty chart

Duty chart (3~400 V)

3~400 V, 50 Hz, p = 1 kg/dm3, v = 1x10-6 m2/s, ISO 9906 Annex A, η = pump efficiency



NEMA connection

Standardised connection


Integrated non-return valve

Without non-return valve


AC motor

Three-phase motor

Direct activation

Star-delta activation


FC operation

Motor with cast stator

Rewindable motor


Oil motor filling


Water-glycol motor filling

Drinking water motor filling


Hydraulics/motor preassembled


Horizontal installation

Vertical installation


Motor temperature monitoring, PT100


PTC motor temperature monitoring


Capacitor box for 1~230 V

Dry-running protection


Integrated lightning protection



Bearing brackets for horizontal installation


Cooling jacket


Non-return valve


Pressure shroud



Pump housing


Pump housing (special version)




Impeller (special version)


Motor housing


Motor housing (special version)



Certification Booklet Wilo-Sub TWI

Article Number 6080451
Edition 1612
Version number 02
Page format A4
Number of pages 14

PDF (397 kB)


Certification Booklet Wilo-EMU D/DCH/K/KD/KM/NK/SCH / Wilo-Sub TWI/TWU / Wilo-Zetos K8 (w/o motor)

Article Number 6080455
Edition 1702
Version number 02
Page format A4
Number of pages 71

PDF (1 MB)


Certification Booklet Wilo-EMU NU/U-Motor

Article Number 6080454
Edition 1702
Version number 01
Page format A4
Number of pages 8

PDF (427 kB)


General overview

Page format A4
Number of pages 72

PDF (46 MB)


Clean Water

Edition 2017
Page format A4
Number of pages 24

PDF (8 MB)


Wilo-Sub TWI 4…, TWI 4-…-QC

Article Number 6061724
Edition 1110
Version number 01
Page format A4
Number of pages 28

PDF (529 kB)



PDF: Wilo-Sub TWI 4


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