Wilo-Sub TWI 6 | Wilo
Your advantages
Wilo-Sub TWI 6

Your advantages

  • Long service life thanks to corrosion-resistant stainless steel, optionally available in V4A quality
  • Individually configurable motors and materials to ensure reliable operation in all applications
  • Drinking water versions with ACS approval
  • 4", 6", 8" and 10" versions for high flexibility
  • Volume flow performance from 1 to 250 m³/h
Series description
Sub TWI 6


Multistage 6" 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 of the water level
  • For pumping water in industrial applications
  • For pumping water without long-fibre and abrasive constituents


  • Multistage submersible pump with radial or semi-axial impellers
  • Integrated non-return valve
  • NEMA coupling
  • Three-phase current motor
  • Hermetically sealed motors
  • Rewindable motors



Wilo-Sub TWI 6.18-04-C-SD


Submersible pump


Diameter of the hydraulic unit in inches ["]


Rated volume flow [m3/h]


Number of hydraulic stages


Series generation


Motor shroud in 1.4571, motor connection via flat male tab


Starting mode Without = direct starting SD = star-delta starting

Technical data

  • Mains connection: 3~400 V, 50 Hz
  • Submerged operating mode: S1
  • Fluid temperature: 3 – 30 °C
  • Minimum flow rate at motor:
    • Hermetically cast motors: 0.08 - 0.16 m/s
    • Rewindable motors (SD-R): 0.1 - 0.5 m/s (depending on type)
  • Max. sand content: 50 g/m3
  • Max. number of starts: 20/h
  • Max. immersion depth:
    • Hermetically cast motors: 350 m
    • Rewindable motors: 100 m
  • Protection class: IP68
  • Pressure connection: Rp 2½ - Rp 3


  • Hydraulics housing: Stainless steel 1.4301
  • Impellers: Stainless steel 1.4301
  • Hydraulic shaft: Stainless steel 1.4057
  • Motor housing: EN-GJL or stainless steel 1.4301
  • Motor shaft: Stainless steel 1.4305 or 1.4301


Submersible pump with ACS approval for vertical or horizontal installation.


Multistage submersible-motor pump with 4" or 6" 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.


Three-phase motor for direct and star-delta start. Sealed, hermetically cast motor with enamel-insulated winding, resin-impregnated, or rewindable motor with PVC-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 system. Standard models are without mounted non-return valves. The maximum inlet pressure is 10 bar.

Delivery state

  • Hydraulics and motor ready assembled
  • 4/5/10 m connection cable approved for drinking water (cross-section: 4x2.5 mm2 or 4x4 mm2)
  • Installation and operating instructions

Installation and operating instructions

Wilo-Sub TWI 4-6

Article Number 4069717
Edition 0801
Page format A4
Number of pages 60
PDF (3 MB)

Wilo-Sub TWI 4-6

Article Number 4069717
Edition 0801
Page format A4
Number of pages 15
PDF (891 KB)

General overview (Documents)

General overview 2019 International version

Article Number 2200591
Edition 2018
Page format 209.9 x 297.0 mm
Number of pages 74
PDF (40 MB)

General overview 2021 International version

Article Number
Edition 2020
Page format 209.9 x 297.0 mm
Number of pages 74
PDF (10 MB)

Certification booklet


Article Number 6080454
Edition 1702
Page format A4
Number of pages 8
PDF (417 KB)

Wilo-EMU D/DCH/K/KD/KM/NK/SCH / Wilo-Sub TWI/TWU / Wilo-Zetos K8

Article Number 6080455
Edition 1702
Page format A4
Number of pages 71
PDF (1 MB)

Wilo-EMU D/DCH/K/KM/SCH (w/o motor)#Wilo-Sub TWI/TWU (w/o motor)#Wilo-Actun ZETOS-K8 (w/o motor)#Wilo-Actun ZETOS-K10 (w/o motor)

Article Number 6080455
Edition 2021-06
Page format 209.9 x 297.0 mm
Number of pages 72
PDF (7 MB)

Certificate REACH (Documents)

REACH regulation

Edition 2020-08
Page format 209.9 x 297.0 mm
Number of pages 2
PDF (158 KB)

Certificate (Documents)

Wilo-Sub TWI

Article Number 6080451
Edition 1612
Page format A4
Number of pages 14
PDF (388 KB)
Product list
Number of results: 95
0.55 … 37 kW
Product descriptionMotor diameter ØRated power P2Minimum efficiency index (MEI)ConnectionArticle number