Protector F1 is a market-leading inhibitor which prevents corrosion and limescale formation in central heating systems. This high-performance product offers superior protection by uniquely combining three inhibitors of organic particles, which bind to the metal within the heating system to protect from debris alongside anodic inhibitors which react with the system’s metal surface to create a protective layer, and cathodic inhibitors that combine with hard water salts to form an insoluble layer.
Fernox Protector F1 also includes enhanced pH buffering to ensure the system water pH level does not drop below 6.5 or above 8.5 – the optimum pH range for preventing corrosion and limescale build-up. In line with BS 7593:2019 regulations and best practice, and for long-term protection of the system, concentration levels should be maintained and checked annually as part of the boiler or system service. Protector F1 is compatible with all other Fernox products and is suitable for use with all materials and metals used in central heating systems, including aluminium.
Fernox Protector F1 gives long-term protection of domestic central heating systems against internal corrosion and limescale formation. It is suitable for all types of boiler, radiators and pipework systems. Protector F1 is compatible with all metals and materials commonly used in central heating systems. It is suitable for use with all types of water, including softened water and deionised water. A single dose of this product treats and protects a larger sized property with a heating system of 130 litres, up to 16 radiators, or 250 sqm of underfloor heating. For open vented systems add via the feed and expansion tank. For sealed systems add via a suitable dosing point (e.g. a towel rail, or an in-line system filter). Alternatively, use a suitable dosing vessel to inject the product into the system.
In single feed indirect cylinders, e.g. ‘Primatic’ or similar, potable water chemicals must be used. Protector F1 has been formulated to have best-in-class pH buffering ability, which keeps system water pH between 6.5-8.5, giving optimum protection for mixed metal systems. To comply with BS 7593:2019, Protector F1 levels should be checked annually. The concentration of the product can be easily measured on site using a Fernox Express Inhibitor Test, Protector Test Kit or by using the Fernox Water Quality Test postal service. BS 7593:2019 also states that after 5 years systems should either be re-dosed, or a laboratory test performed, such as the Fernox Water Quality Test.
“If you protect a central heating system using Fernox Protector F1, after cleaning with Fernox Cleaner F3, you can restore and maintain system efficiency, resulting in a gas saving of up to 15% every time you heat your room. This saving is equivalent to 110 Kg CO2e per typical home per year.” independently verified.
Fernox Protector F1 is supplied in 500 ml bottles.
Fernox Protector F1 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.
Protector F1 is a blend of inorganic and organic corrosion and scale inhibitors.
Form: Light yellow liquid
Odour: Slightly aromatic
pH (conc.): 8.3
pH (in-use): 7.8-8.5
SG: 1.14 at 20 °C
Single Unit Dimensions
Single Unit Barcode
Outer Carton Dimensions
Outer Carton Barcode (ITF)
52 × 88 × 182 mm
195 x 265 x 180 mm