Cleaner F3 265ml

Product Code: 62455

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Fernox Cleaner F3 265ml is a universal, fast-acting and effective pH neutral cleaner for central heating systems.


  • Universal cleaner for pre-commissioning new systems in accordance with BS 7593:2019
  • Removes sludge, limescale and installation debris
  • Suitable for use on new and existing systems to optimise efficiency
  • Compatible with all metals and materials in heating systems, including aluminium
  • Smaller volume product – less packaging waste and lower environmental impact
  • pH Neutral, non-hazardous formulation

Fernox Cleaner F3 265ml is a universal, fast acting and effective pH neutral cleaner for central heating systems. It is designed to remove debris, sludge and scale from existing systems. In this way, it will restore heating efficiency and eliminate or reduce boiler noise. It has also been designed for pre-commission cleaning of new installations in accordance with BS 7593:2019, removing flux residues and other debris to help extend the life of a system.

Part of the tried and tested Fernox Cleaner range, this, this 265ml product offers reduced packaging and waste without compromising on high performance, quality and ease of use. This conveniently size bottle can treat an average 100 litre system or 12 radiators and maybe dosed via a TF1 Filter.

Cleaner F3 can be used for all types of cleaning methods; manual or magnetic flushes and for older, sludged systems, Cleaner F3 can be used in conjunction with a powerflushing unit. If an existing system is heavily contaminated repeat applications of Cleaner F3 maybe used or the use of Fernox Power Cleaner F8 may be required. If the system is heavily scaled the use of Fernox DS40 System Cleaner and Descaler is recommended. Cleaner F3 is a neutral, non-hazardous product that is well inhibited and compatible with all metals and materials, including aluminium, commonly used in heating systems.

For continued long term protection systems should be thoroughly cleaned and flushed in accordance with BS 7593:2019 and Benchmark using Fernox Cleaner F3, before treating with Fernox Protector F1. Inhibitor levels should be checked regularly as part of the annual maintenance service.

Cleaning a central heating system using Fernox Cleaner F3 and protect with Fernox Protector F1 can restore and maintain system efficiency resulting in a gas saving of up to 15% every time you heat your room.

Application One 265 ml bottle of Cleaner F3 is sufficient to clean an average domestic central heating system (100 litres). Additional/repeat applications of Cleaner F3 may be used for larger, dirty systems. Alternatively, Power Cleaner F8 may be used for heavily contaminated systems. First, drain and refill the entire system with plain water. For optimum results, the entire system, including drop feed radiators where fitted, should be completely drainable. Preferably, full bore gate valves with hose connectors should be provided temporarily for this purpose. Motorised and thermostatically controlled valves must be set so that no part of the system is closed off during cleansing or rinsing. Discharges must be made to the foul drain and not to surface water drain. For open vented systems add Cleaner F3 via the header tank. For sealed systems add via a suitable dosing point or TF1 Filter or use Fernox Cleaner F3 Express 400ml. Fernox Cleaner F3 can also be used in conjunction with a powerflushing unit. In this case, please refer to the unit manufacturer’s instructions. When pre-commission cleansing new systems, Fernox Cleaner F3 should be circulated for a minimum of one hour at normal operating temperature. For cleaning existing systems, sludge and debris should be dispersed also within one hour at normal operating temperatures. However, to remove hardened iron oxides and limescale, the cleaning time can be extended to up to one week under the normal heating cycle. If a radiator still has a cold spot after one hour, increase the flow through the radiator by closing the valves on the other radiators. An additional or repeat dose of Cleaner F3 may be necessary in some cases. Drain and flush thoroughly, at least twice, until the water runs clear. When using Cleaner F3 with a powerflushing machine, cleaning should be completed within an hour. Use dynamic flushing with plain water until the water is clear. Refill system adding Fernox Protector F1 for long-term protection against corrosion and limescale. In single feed indirect cylinders, e.g.”Primatic” or similar, potable water chemicals must be used. Packaging, Handling and Storage Fernox Cleaner F3 is supplied in 265ml bottles. Fernox Cleaner F3 is classified as non-hazardous for human health, but as with all chemicals keep out of reach of children. In case of contact with eyes or skin, rinse immediately with plenty of water.