What is “Sidestream Filtration”?

Recirculating heating or cooling water systems frequently suffer from a build-up of solids and sludge generated by corrosion, scale deposition and solids in the feed water as well as swarf and debris from initial construction. Left in situ these solids can severely impact the performance and energy efficiency of a closed system, block heat exchangers, promote bacterial growth and promote further corrosion.

Our side stream filters are simple to retro fit to your existing heating or cooling system. It will provide continuous filtration of the water in the system with zero water loss through its closed recovery system. There is no need to back wash or flush the side stream filter.

The Culligan products and technology used in these applications represent an ongoing commitment to delivering the very best water treatment solutions for our customers. As a result of continuous development and review, the Culligan range is one of the most comprehensive available within the market today.

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Please note: we are only able to handle enquiries from within the United Kingdom.

Why chose our “Culligan SSF” range of Commercial and
Industrial Sidestream Filters?

The SSF series of cyclone filtration systems are designed for a side-stream flow of water, drawn from the system by the circulation pump built into the SSF units, thats pumped through the cyclone filter where suspended solids or sediment are separated by centrifugal force. The cleaned filtered water is then returned to the system. Suspended solids collected in the filter are periodically purged to drain manually or automatically with minimal loss.

Continuous filtration of closed water systems removes suspended solids and protects control valves and sensitive equipment from damage and blockages whilst maintaining system efficiency and performance.

Typical Appliactions

  • Heating and Chilling Water Systems
  • Fan Coil Systems incorporating Heat Pump Units
  • Systems with Plate Heat Exchangers
  • Old Systems being Renovated or Updated (replacement boilers, etc)
  • Glycol and Brine Systems


  • Continuous filtration with no Backwashing or Flushing required
  • Minimum water lost during purging – closed recovery system provides Zero Water Loss
  • Suitable for a wide range of temperatures and pressures including high temperature hot water and chilled water systems
  • Our unit is SKID mounted, meaning easy installation for new/existing systems
  • Independent of system operation and flow

Compact Packaged System

Compacted sized unit complete with pump and controls provide a high flow filtration system with minimal space requirement. Readily manhandled into position with no site assembly or lifting requirement.


The SSF Series units will remove metal oxides, precipitated hardness ssalts and other seperable solids down to less than 5, 10 or 20 microns on continuous re-circulation.

Installed n connection with the standard cyclone filtration unit, this unit collects the filtered solids in a retaining bag without water loss from the system.

A Monitor with volt free (BMS) contacts is available to indicate when the collector bag is full and requires emptying.

Our Dynamic Seperator

Our Dynamic Seperator uses the centrifugal movement of water to seperate the solids from the liquid down to less than 5, 10 or 25 micron on continuous re-circulation.

Water enters the top of the unit tangentially and is drawn into the chamber where the seperation of solids from water occurs.

The water is accelerated into a rotary motion and flows down this chamber where the centrifugal force seperates solids having higher specific weight. The solids fall by gravity to the collection chamber at the base of the unit.

Water freed from suspended solids is drawn into the central vortex and up to the seperator outlet.

Where would you Typically Install a Sidestream Filter?

The Feed Flow to the Sidestream Filter should be connected to the bottom of the circuit header to help purge debris from the circuit.

The Return Flow from the Sidestream Filter should ideally be connected to the top of the circuit header. Alternatively, it can be connected to the base.

The Feed & Return connections should be at least 500mm apart, preferably further, to avoid back-circulation.

Connections and Piping from the closed water circuit must be equal or larger than the size of the Sidestream Filter pump inlet. Use of smaller connections will reduce flow causing reduced performance of the Dynamic Seperator.

Lagging/trace heating may be required if the unit is located in a position subject to freezing.

The Sidesteam Filter should be drained if it is to be shut down and may be subject to freezing.

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