Fernox Cleaner F3 (265 ml) is a central heating system cleaning additive designed to help remove installation debris, oils, flux residues, and loose corrosion products from new or existing heating circuits. It prepares the system water for effective corrosion protection and improves overall efficiency.

Function & Purpose

During installation, servicing, or repair work, contaminants such as soldering flux, metal filings, and rust particles can remain in the heating system. These impurities can reduce flow, impair heat transfer, and contribute to cold spots on radiators or noisy pump operation. F3 Cleaner breaks down and disperses these contaminants so they can be flushed out of the system before adding a long-term corrosion inhibitor.

Compatibility

This cleaner is suitable for use in sealed central heating systems including combi, system, and conventional boiler installations. It is formulated to be compatible with common heating system materials such as steel, copper, and aluminium when used according to instructions.

How It Works

The 265 ml bottle is added to the system via a suitable access point such as a filling loop or filter connection. Once introduced, the system should be run under normal operating conditions for a recommended period to allow the cleaner to circulate and interact with contaminants. After the cleaning period, the system must be thoroughly flushed with clean water to remove the suspended debris. Following flushing, a corrosion inhibitor should be added to protect the system long term.

Key Benefits

Using Fernox F3 Cleaner helps improve heat transfer and circulation by removing soluble and suspended contaminants early in the system’s life or after servicing. Cleaner system water supports quieter operation, more even radiator heating, and reduced risk of performance issues caused by debris build-up. Removing contaminants also allows corrosion inhibitors to work more effectively.

Ideal Applications

F3 Cleaner is ideal for new central heating installations, boiler upgrades, or systems that have been drained and refilled after repair work. It is commonly used as part of a complete system preparation process—cleaning first, then flushing, and finally protecting with a corrosion inhibitor.

Usage Note

Always follow the manufacturer’s dosing and safety instructions. After cleaning and flushing, add a suitable corrosion inhibitor or conditioner to ensure lasting protection against corrosion and scale formation.