Closed loop pre-treatment cleaning

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What is closed loop pre-treatment cleaning?

Closed loop pre-treatment cleaning (CPC) is an advanced water treatment process designed to prepare closed heating and cooling systems for commissioning in accordance with BSRIA BG29:2021. The process uses chemically treated or filtered water circulated through the system to remove contaminants, reduce bacterial activity, and prevent early corrosion or fouling.

At Complii, we use purpose-built CPC rigs equipped with proportional dosing, filtration, and microbiological control technology to ensure optimum system cleanliness before commissioning. This process allows for dynamic flushing using side-stream or full-flow filtration, significantly reducing water consumption and minimising environmental impact.

Closed loop pre-treatment cleaning is ideal for projects where water discharge is restricted or where sustainability and compliance are priorities.

Why choose Complii?

How we can help.

Protect your people, property, and business. Here’s why we’re the right choice for closed loop pre-treatment cleaning.

Water-efficient and environmentally responsible

CPC significantly reduces the amount of water required for flushing by recirculating treated water through filtration systems. This saves thousands of litres compared with traditional methods and supports sustainable building practices.

Prevents corrosion and microbiological fouling

Pre-treatment water contains chemical inhibitors and microbiological control agents that protect pipework, coils, and components during filling and pressure testing, reducing early corrosion and bacterial contamination.

Compliant with BSRIA BG29:2021

All CPC works are completed to the latest BSRIA BG29:2021 guidance, ensuring the system meets industry standards for water cleanliness and commissioning readiness.

Ideal for restricted or sensitive sites

CPC is especially effective where site conditions limit access to mains water or where trade effluent discharge is restricted. It enables safe and compliant cleaning with minimal disruption.

Integrated microbiological protection

Each CPC unit can be fitted with advanced filtration stages and optional UV sterilisation, providing a highly effective 99.99% removal rate for bacteria, viruses, and organic contaminants.

Proven performance and measurable results

Our CPC rigs deliver real-time monitoring of flow, pressure, and water quality, with chemical and microbiological testing conducted during and after cleaning to confirm compliance.

Your questions answered.

CPC removes debris, flux residues, and other contaminants before a system is commissioned. It ensures that the water used during filling and testing supports corrosion control and microbiological stability.
Unlike traditional chemical cleaning, CPC uses filtration and controlled dosing to clean the system without large water discharges. It can operate as a closed process, reducing environmental impact and conserving water.
CPC should take place during the system filling and pressure testing stages, before the system is balanced or brought into service. This ensures protection and cleanliness from the start.
CPC can be used on all closed heating and cooling systems, including LTHW, CHW, MTHW, and condenser circuits, particularly where large volumes or complex installations are involved.
Yes. Our CPC units can include in-line UV sterilisation for enhanced microbiological protection. UV treatment achieves over 99.99% effectiveness against bacteria and viruses.
Once water testing confirms the required chemical and microbiological standards, the CPC unit can be removed or left in place temporarily to maintain water quality during commissioning.

Closed loop pre-treatment cleaning.

What is closed loop pre-treatment cleaning?

How we can help.

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