Antifreeze Protector Alphi-11 is a combined antifreeze and inhibitor product, which provides protection against internal corrosion and limescale formation in domestic central heating systems . Antifreeze Protector Alphi-11 is suitable for use with all metals and materials commonly used in heating systems. For long-term protection ensure concentration levels are maintained and checked annually as part of the boiler or system service. Available as 25 litre liquid product, Non-toxic, environmentally friendly formulation,NSF CIAS , KIWA and Belgaqua approved. Antifreeze Protector Alphi-11 is compatible with all other Fernox products.
The minimum recommended ‘in-use’ concentration of the product is 25% in order to ensure adequate corrosion protection. This concentration will protect down to -11°C. A concentration of 40% will protect down to -22°C. Alphi-11 Antifreeze Protector can be introduced via the feed and expansion tank, or injected directly into the system via a suitable point (e.g. dosing pot). Introduce into the system after draining off a quantity of water at least equal to the amount of Alphi-11 to be added. Engage the circulating pump and have the system online for a few hours in order to achieve an even distribution.
Concentration 25% 30% 35% 40%
Protection -11°C -15°C -18°C -22°C.
In single feed indirect cylinders, e.g. “Primatic” or similar, potable water chemicals must be used. We recommend untreated systems are thoroughly cleansed and flushed, in accordance with BS 7593:2019 and Benchmark, using Fernox Cleaner F3, before treating with Fernox Alphi-11 Protector, as existing debris can damage the installation.
Fernox Alphi-11 Antifreeze Protector is supplied in 5 and 25 litre containers.
Fernox Alphi-11 Antifreeze Protector is classified as non-hazardous and non-irritant, but as with all chemicals, keep out of reach of children. Do not mix with other chemicals, with the exception of Fernox products. Do not take internally. In case of contact with eyes or skin, rinse immediately with plenty of water.
Fernox Alphi-11 Antifreeze Protector contains mono-propylene glycol.
Odour: Aromatic (slight)
Form: Clear liquid
pH (conc.) 6.9
pH (25% solution): 6.4 – 7.4
SG: 1.04 at 20°C
Single Unit Dimensions
Single Unit Barcode
Outer Carton Dimensions
Outer Carton Barcode (ITF)
250 × 280 × 445 mm
x x mm