Wilo-Drain STS 40

Series description


Submersible sewage pump for intermittent operation for stationary and portable wet well installation.


Pumping of

  • Sewage containing faeces
  • Pre-cleaned sewage without faeces and long-fibre components
  • Wastewater

Type key

E.g.:Wilo‐Drain STS 40/10‐A
STSTauchmotorpumpe (submersible pump)
40Nominal diameter [mm]
10Max. delivery head [m]
AWith float switch

Special features/product advantages

  • Attached float switch (A-model) enables easy operation
  • Integrated pump base for easy installation
  • Impeller made of stainless steel
  • Low weight

Technical data

  • Mains connection: 1~230 V, 50 Hz or 3~400 V, 50 Hz
  • Immersed operating mode: S1 or S3 25%
  • Protection class: IP 68
  • Insulation class: B
  • Thermal winding monitoring
  • Max. fluid temperature: 3 - 35 °C
  • Cable length: 10 m
  • Max. immersion depth: 7 m
  • Free ball passage: 40 mm


  • Ready-to-plug single-phase version
  • A-model version including float switch
  • Thermal motor monitoring


Submersible sewage pump as submersible monobloc unit for stationary and portable wet well installation.


The outlet on the pressure side is designed as vertical screwed connection Rp 1½. Vortex impeller are used as the impeller shapes.


Glanded motors give off their heat directly to the surrounding fluid via the housing components and can be used in immersed state for permanent or intermittent operation.

A sealing chamber protects the motor from fluid ingress. The filling fluid used is potentially biodegradable and environmentally safe.

The single-phase AC motors are equipped with shockproof plugs, and A-model versions with float switches. The three-phase motors are equipped with bare cable ends.


Sealing on the fluid side is achieved by a bidirectional mechanical seal, while sealing on the motor side is achieved by a rotary shaft seal.


  • Pump housing: EN-GJL-250
  • Pedestal: grey cast iron
  • Impeller: stainless steel 1.4301
  • Shaft: stainless steel 1.4404
  • Mechanical seal on pump side: carbon/ceramic
  • Shaft seal on motor side: NBR
  • Static gasket: NBR
  • Motor housing: stainless steel 1.4301

Scope of delivery

  • Pump ready for connection with 10 m connection cable
    • For 1~230 V with shock-proof plug
    • For 3~400 V with bare cable end
  • A-model version with attached float switch
  • Installation and operating instructions


  • Non-return valve and gate valve
  • Various pressure outlets and hoses
  • Switchgears and relays

Duty chart

Drain STS 40




Single-channel impeller


Vortex impeller

Multi-channel impeller


Open multi-channel impeller






Sealing chamber

Leakage chamber


Sealing by mechanical seal on motor side


Sealing by rotary shaft seal on motor side

Sealing by mechanical seal on fluid side

AC motor

Three-phase motor

Direct activation

Star-delta activation


FC operation


dry motor

Motor with oil cooling


Dry motor with closed-circuit cooling



Wet well installation, stationary


Wet well installation, portable

Dry well installation, stationary


Dry well installation, portable



Motor leakage monitoring


Sealing chamber monitoring


Leakage chamber monitoring


Motor temperature monitoring, bimetal

PTC motor temperature monitoring


Explosion protection


Float switch

Version A

Capacitor box for 1~230 V





Pump housing

Cast iron


Cast iron

Motor housing

Stainless steel


General overview

Edition 2017
Page format A4
Number of pages 72

PDF (46 MB)


Wilo-Drain STS 40/...A, STS 40/...

Article Number 2068717
Edition 0701
Version number 01
Page format A4
Number of pages 13

PDF (1 MB)



PDF: Wilo-Drain STS 40


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