Leak Sealer F4 is a internal leak sealer developed for use throughout a central heating system to seal small, inaccessible leaks and weeps which may cause pressure loss and boiler breakdown. Once dispersed within the system, the product finds the area of oxygen ingress and forms a polymer to seal the pinhole. Effective within 1-24 hours after application, the unique sealing efficiency of this market-leading water treatment chemical has been proven to prevent blockages or restrictions within the boiler or vulnerable system components such as pumps and safety devices. A leak can be quickly and efficiently sealed, without the need for a complete system drain down.

• Ideal for reducing pressure loss from sealed systems
• Seeks out and seals inaccessible, internal microscopic leaks fast
• Saves time and money on draining down the system and repair costs
• Safe to use – does not cause blockages in pipework or vulnerable boiler components such as pumps, air vents and heat exchangers
• Designed to be left permanently in the system – compatible with all metals and materials, including aluminium
• One 500ml recyclable bottle treats up to 130 litres of system water (16 radiators) and the equivalent of 250m2 of underfloor systems.