WFF300 WISY Vortex Rainwater Filter

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The WISY WFF300 Vortex Filter is designed to separate solids from water and can be used for large buildings with 32,290 SF of roof area or for industrial water treatment. A single unit can filter precipitation off of up to 32,290 sq. ft. of roof area to be reused for site irrigation, toilet, and urinal flushing, janitorial use, laundries, fire protection, evaporative cooling tower make-up, process water, or other non-potable uses.

The WFF300 is suitable for below or above ground collection systems. The unit directs debris to the stormwater system and diverts up to 95% of filtered rainwater to a rainwater storage tank. Multiple WFF300 units can be used to cover larger roof areas greater than 32,290 sq. ft. RMS does not recommend the WFF300 to be used when collecting from green-roofs.

The Short WFF300 Vortex Filter can be used when there are piping elevation restrictions. The inlet and outlet elevation height difference of the Short WFF300 is 12.6”, 5.7” shorter than the standard WFF300 (18.25”).

Design Principle

The harvested rainwater flows out of the horizontal inlet pipe into the WFF300 and is drawn in a circular (vortex) motion from inflow level down to the filter insert.  By exploiting water’s natural adhesive forces, the harvested rainwater is drawn through the vertical fine filter and passes through the clean water outlet into the storage tank.  The filtered dirt particles are then diverted to the storm drain.  

The filter insert cannot reach its maximum efficiency until the filter mesh has become completely saturated with water.  This process can take up to 2 minutes if the filter insert was initially completely dry.  During this period, the initial dirt particles from the roof are flushed directly to the storm drain.  This is why the vortex filter can function as a “first flush” rainwater pre-filter and thus meets the requirements defined by ARCSA/ASPE/ANSI Standard 63 for Rainwater Catchment Systems.  


Collection Area: 32,290 ft.

Filtering Efficiency: Up to 222 GPM (14 l/s) (over 90%)

Standard WFF300 with Composite Lid - WF 3010 (alternate part # RH9521-12PC)

Standard WFF300 with 60-ton Rated Steel Lid - WF 3001 (alternate part # RH9521-12XH)

Short WFF300 with Composite Lid - WF 3020

Short WFF300 with 60-ton Rated Steel Lid - WF 3023

Inlet and Outlet elevation difference for WFF300: 18.25 in

Inlet and Outlet elevation difference for Short WFF300: 12.6 in

Housing components: Polypropylene (PP)

Sealing rings: EPDM

Filter insert and mesh, end ring, baseplate, lifting handle material: Stainless-steel 1.4301

Filter mesh: 380 microns 

Rainwater inlet (collar): 12 in.

Clean water outlet: 8”

Debris outlet: 12” 

Dry Weight: with steel cover 238 lbs.;   

Each WFF300 Vortex Filter includes:

  • Polypropylene Filter Housing with 12” inlet, 12” debris outlet, 8” filtered water outlet
  • 380 Micron Stainless Steel Filter Insert 
  • Baseplate
  • Lifting Handle
  • Housing cover (polyethylene or steel)
  • Rotating upper and bottom half of housing for custom installation

Spare Parts:

  • 380 Micron Stainless Steel Filter Insert - WE 0307
  • 380 Micron Stainless Steel Filter Insert coated with Titanium Nitride (for high levels of abrasive stress) - WE 0406
  • 180 Micron Stainless Steel Filter Insert - WE 0311
  • 380 Micron Stainless Steel Filter Insert for the Short WFF300 - WF 0310
  • Steel Lid with 60-ton capacity - WF 4001
  • Lifting Handle - WA 0305

Accessories for WFF300:

  • Extension tube (48” increments) - WV 1030
  • Intermediate ring for connection - RS 1020
  • Extension Handle
    • 20 in - WA 0307 (alternate part # RH9521EX20)
    • 36 in - WA 0309 (alternate part # RH9521EX36)
  • Blind Insert - BE 0306
  • Sieve Basket (aka soakaway strainer) - VS 0310
  • End ring with child safety device (required for steel lid) - RA 1020
  • Cleaning spray nozzle, pump without timer - SC 3000

*contact RMS representative for Short WFF300 accessories




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WFF300 WISY Vortex Rainwater Filter
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