Sidestream Filters 

Sidestream filtration diverts a small percentage (typically 5–15%) of fluid from the main loop (like HVAC or chilled water systems) through a particulate filter. This continuous cleanup removes rust, sludge, and scale, protecting the entire system without disrupting main flow.

You offer three variants:

• SideLoop filters – Compact, inline filters
• Packaged Skid systems – Pre-assembled units with pumps and vessels
• Continuous Disk filters – Self-cleaning, automatic disk systems.

Common uses include:

• HVAC closed-loop systems
• Cooling tower makeup water
• Boiler feed water protection
• Industrial process loops

It enhances system longevity, reduces corrosion, and improves heat transfer. 

Read more in our “Sidestream Filtration and the Benefits to Building Services” blog.

Sizing is based on main system flow and particulate load. Use filter curves and your flow to calculate a differential pressure of 50 to 100 mbar at the 5-15% of total flow. This leads to the best balance between initial capital costs and running costs leading to optimal filter lifetime costs.

See our “Filtration System Optimal Sizing” post for further discussion of lifetime cost considerations and sizing data

Housings are typically stainless steel or carbon steel with corrosion-resistant coatings.

Filter media vary: micron-rated stainless mesh cartridges for general cleanup, or meltblown polypropylene filter for unfiltered systems and pleated polypropylene filter media for finer filtration in critical loops.

They typically remove particles 5 µm and larger with >99.9% plus efficiency, depending on media. SideLoop and Packaged Skid systems with micron-rated cartridges are widely effective.

Cartridge filters generally require quarterly inspection, but replacement depends on differential pressure drop. Once this exceeds 2 bar consider change, but definitely prior to 2.5 bar. 

Refer to “What Issues Cause You to Consider Changing Filtration Systems” for troubleshooting guidance.

Yes! By cleaning sideflow, filters prevent scale and fouling in main heat exchangers, leading to improved efficiency and reduced energy costs across the system.

Yes - packaged skid systems can operate at pressures up to 10 bar and temperatures to 95 °C, depending on design. Always confirm temperature and pressure ratings to match your system.

Sidestreams should be located at a low point in the system for effective dirt removal. Ideally near pump return lines, with isolation valves and a safe bypass. Use flexible hoses or flanged connections for retrofit ease.

Install a differential pressure gauge across the filter cartridge. A rising differential pressure drop over 2.0 bar indicates clogging and replacement is necessary before 2.5 bar.

Yes - by continually removing suspended particles and limiting stagnant zones, filters reduce biofilm formation in HVAC loops. Regular dosing of biocides, as part of the system, complements this clean-up effect.