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Wilo-Flumen OPTI-RZP 20 ... 40 | Wilo
Your advantages
Wilo-Flumen OPTI-RZP 30

Your advantages

  • Reliable continuous operation due to low clogging propellers and flow housing that is pump in non-clog design.
  • High operational reliability by using stainless steel investment-cast propellers
  • Reduction of energy costs thanks to high pump efficiency
  • Customer-specific configuration taking into account the different pipe diameters and volume flows
  • Simple adaptation to the system parameters through operation with a frequency converter
  • Easy installation and removal, even when the basins are filled due to lowering devices and screwless coupling
  • Simple replacement due to adaptation to existing installations

Recommended services

Series description
Wilo-Flumen OPTI-RZP


Recirculation pump: Submersible mixer, directly driven with attached flow housing.


  • Recirculation between nitrification and denitrification in the biological wastewater treatment
  • Returning return activated sludge to the activated sludge tank or for sludge treatment
  • Water circulation for aquaculture (fish farming)
  • Special applications


For pumping in commercial areas of:

  • Sewage containing faeces
  • Return activated sludge
  • Process water


  • Thermal motor monitoring with bimetallic strip
  • Flow housing
  • Operation with frequency converter possible



Wilo-Flumen OPTI-RZP 40-1.95-6/24Ex S8


Submersible mixer, horizontal


Series: Recirculation pump with standard asynchronous motor


x10 = nominal propeller diameter in mm




Rated propeller speed in rpm


Number of poles


x10 = stator pack length in mm




Propeller code for special propeller (omitted for standard propeller)

Technical data

  • Mains connection: 3~460 V, 60 Hz
  • Fluid temperature: 37 … 104 °F
  • Submerged operating mode: continuous duty (S1)
  • Protection class: permanently submerged (IP68)
  • Insulation class: H
  • Max. switching frequency: 15/h
  • Max. immersion depth: 66 ft


  • Motor housing: ASTM A 351 or ASTM A48 Class 35/40B
  • Seal housing: ASTM A 351
  • Seal:
    • On the motor side: SiC/SiC or nitrile
    • Fluid side: SiC/SiC
  • Propeller: ASTM A 351



Propeller made of solid material with clogging-free propeller geometry. Pump in non-clog design flow housing with guide claw and two flange claws. The guide claw ensures smooth function when lifting and lowering the recirculation pump. The flange claws can be readjusted, ensure optimum centring on the discharge pipe and stabilise the recirculation pump at high operating pressure.

Alternative version with flange connection for direct screwing to the discharge pipe.


Surface-cooled submersible motor in three-phase current design with permanently lubricated und large-size rolling bearings. The motor winding is equipped with temperature monitoring. The motor heat is given off directly to the surrounding fluid via the motor housing. The connection cable is designed for heavy mechanical loads, sealed water pressure-tight against the fluid and is sealed longitudinally watertight. The connection cable has bare cable ends and is 33 ft long as standard.


Large-volume sealing chamber with double shaft sealing. The sealing chamber is filled with white oil and absorbs the leakage from the seal on the fluid side. A corrosion- and wear-resistant mechanical seal is used on the fluid side. The seal on the motor side involves either a rotary shaft seal or a mechanical seal.

Scope of delivery

  • Recirculation pump with attached flow housing and connection cable
  • Installation and operating instructions


  • Thermal motor monitoring as temperature controller and temperature limiter
  • Thermal motor monitoring with PTC sensor
  • Fluid temperatures up to 140 °F, depending on the motor type and motor capacity
  • Sealing chamber monitoring
  • Ex-rated in accordance with ATEX, FM and IEC-Ex
  • Ceram coating for housing parts made of grey cast iron


  • Lowering device
  • Auxiliary lifting device
  • Cable bollard to secure the hoist cable
  • Additional rope anchoring
  • Fixation sets with anchor bolts

Installation and operating instructions

Wilo-Flumen OPTI-TR 20-1, 22, 28-1, 30-1, 40-1, Wilo-Flumen EXCEL-TRE 20, 30, 40

Article Number 6074717
Edition 2021-10
Number of pages 100
Language en, es
PDF (18 MB)

Wilo-Flumen OPTI-RZP 20-1 ... 40-1, Wilo-Flumen EXCEL-RZPE 20-1 ... 40-1

Article Number 6088799
Edition 2021-10
Number of pages 32
Language en, es
PDF (14 MB)

Certification booklet

Wilo-EMU RZP, Wilo-Flumen OPTI-RZP 20...40, Wilo-Flumen EXCEL-RZPE 20...40

Article Number 6074696
Edition 2022-05
Number of pages 44
Language language neutral
PDF (4 MB)


Recirculation Pumps Brochure (RZP)

Number of pages 24
Language en
PDF (3 MB)