Fernox F4 Express Central Heating Leak Sealer at Boiler Parts Center is part of the Fernox central heating water treatment range from Fernox. The Fernox Leak Sealer F4 Express is used in domestic heating systems for sealing small inaccessible leaks.
The Fernox Leak Sealer F4 Express works best in warm/hot circulating water. Once dispersed evenly in the system water it is effective within 1 - 24 hours. The sealing efficiency of Fernox Leak Sealer F4 Express has been formulated to prevent blockage of safety devices, pumps, etc.
For long term protection against corrosion and limescale we recommend systems are cleaned using Fernox Cleaner F5 Express and inhibited with Fernox Protector F1 Express.
Fernox F4 Express Central Heating Leak Sealer
Quick and convenient – doses in 30 seconds
Simple to use with no mess
Added via a radiator adapter or filling loop supplied
Non-toxic, environmentally friendly formulation
100% recyclable can
Seeks out and seals most weeps and leaks
Saves time and money on draining down and repairing
Does not cause blockages of pumps, air vents, etc.
Compatible with all Fernox Protectors