FERNOX BOILER SEALER 500ML F4

Ideal for reducing pressure loss from sealed systems | Seeks out and seals inaccessible, internal microscopic leaks fast | Saves time and money on draining down and repairing | Safe to use – does not cause blockages in pipework or vulnerable boiler components such as pumps, air vents and heat exchangers | Left permanently in the system – compatible with all metals and materials, including aluminium | One 1 pint recyclable bottle treats up to 34 gallons of system water (16 radiators)