

Product Code: 604003
Fernox Leak Sealer F4 is used throughout domestic heating systems for sealing small, internal, inaccessible leaks. Leak Sealer F4 works best in warm/hot circulating water and once evenly dispersed will usually be effective within 1 - 24 hours. The sealing efficiency of Leak Sealer F4 has been intentionally limited to prevent blockage of safety devices, pumps, etc.