Wilo-Star-ZD Glandless circulating tandem pump with screw connection


  • Twin pumps used in single pump operation and in parallel operation of two pumps.
  • Suitable for installation in any position with horizontal shaft; terminal box in position 3-6-9-12 hours
  • Intra-system bypass circulation to protect against legionella in the standby pump
  • Increased reliability in single pump operation by a standby unit available at all times


Glandless circulation twin pump with threaded connection; speed levels can be preselected for capacity regulation


Potable water circulation systems for industrial and civil engineering applications.


Operation modes

  • Switching speed stages

Manual control

  • Speed step setting (3 steps)


  • Built-in diverter valve in the pump casing
  • Double conduit entry option
  • Internal bypass
  • Quick connection by means of spring clamps
  • Electric motor resistant to blocking currents

Model overview

Those. information

Scope of delivery

  • Pump
  • Seals
  • Installation and Operating Instructions

Explanation of designation

Example: Wilo-Star-ZD 25/6
Star-ZD Double circulation pump for drinking water
25/ Nominal connection diameter
6 Nominal head [m] at flow rate Q=0 m³/h

Technical Specifications

  • Temperature of pumped liquid
    • Drinking water up to 3.21 mmol/l (18 °dH): max. +65 °C, in non-uniform mode (2 h) up to +70 °C
  • Connection to mains 1~230 V, 50 Hz
  • Protection class IP44
  • Nominal diameter Rp 1
  • Max. operating pressure 10 bar


  • Pump casing: bronze
  • Impeller: synthetic material
  • Shaft: ceramic
  • Bearings: graphite impregnated with synthetic resin


Wilo-Star-Z/-ZD Download
Documentation Download



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