Star S 21BFX, 3-Speed Bronze Star Series Circulator, 1/12 HP Zoom

Star S 21BFX, 3-Speed Bronze Star Series Circulator, 1/12 HP


Brand: Wilo

4106179 has been discontinued.
Please contact customer service at
(888) 757-4774 for help finding an alternative.

Do not use this item for any installation or repair of potable water applications. This product does not comply with the "Safe Drinking Water Act," which requires that products meet low-lead standards in order to be used in systems providing water for human consumption (drinking or cooking). This item is for non-potable (non-human consumption) water applications only.




Application: Heating
Material: Bronze
Horse Power:
Max. Amps: 0.92
Phase: 1
Hertz: 60
Max Pressure (PSI): 140
Max. RPM: 2700
Max Flow (GPM): 19
Max Head (Ft): 21
Temperature Range (F): 14°-230°F
Connection Size: 3/4"
Connection Type: Flange Rotated 90 Deg
Type: 3-Speed Pump

Description for Wilo 4106179

Wet rotor circulation pump, with flanged connection. (Flange parallel to shaft). Pre-selectable speeds to adjust the capacity on "S" versions. Bronze body for domestic hot water applications


  • Suitable for any installation position with horizontal shaft; terminal box in 3-6-9-12 o'clock position
  • Three pre-selectable speed stages for load adjustment ("S" type only)
  • Impedance protected motor, motor protection not required
  • Cable entry both sides of terminal box
  • Quick connection spring clips for simple electrical connection
  • Steel Terminal Box
  • Fits all Competitor's Models
  • Powerful Starting Torque
  • Ultra Quiet
  • Reliable Wet Rotor Technology
  • Optional Check Valve
  • Automatically Vented

  • Pump housing: Bronze
  • Impeller: Engineered Composite (PP - 40% GF)
  • Shaft: Stainless steel (Cr)
  • Bearing: Metal-impregnated carbon

Star S 21BFX, 3-Speed Bronze Star Series Circulator, 1/12 HP


by PowerReviews
WiloStar S 21BFX, 3-Speed Bronze Star Series Circulator, 1/12 HP

(based on 1 review)

Ratings Distribution

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Reviewed by 1 customer

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quiet, low power, and lots of head

By steve P

from Milton, NH

Verified Reviewer

Comments about Star S 21BFX, 3-Speed Bronze Star Series Circulator, 1/12 HP:

Note that the illustration is not the flanged version, which fits the description.

I'm using this pump in a solar hot water system, open drainback, with 18 ft head going to the collector. The Wilo handles the head using the medium setting which is about 80 watts - the only pump I could find that could handle the head with so little power. It is virtually silent, much quieter than my Taco 055. Very nice quality in the casting, nice flanges. The only thing I don't like is the electrical connectors - difficult to use with a stiff #14 wire, which is admittedly overkill. Only time will tell if the unit is durable as well. I am very satisfied so far.

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1 Question | 2 Answers
Displaying question 1
  • Star S 21BFX, 3-Speed Bronze Star Series Circulator, 1/12 HP


    Do I need anything additional to connect this pump to 3/4" copper pipe?
    Asked on 11/6/2012 by Steve

    2 answers



      You just sweat it on. Don't over heat and if not sure take the motor/rotor
      off the housing then sweat.

      Answered on 11/7/2012 by Anonymous


      This circulator connects to system piping with a flanged connection. You would need to buy either 3/4" threaded flanges with sweat adapters or 3/4" sweat flanges in order to connect to 3/4" copper pipe.

      Answered on 11/20/2012 by PexSupply Staff from NY
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