Leak Sealer F4 is suitable to be used throughout a central heating system to seal small leaks and weeps which may cause pressure loss and boiler breakdown. Once dispersed within the system it will be effective 1-24 hours after application. The unique sealing efficiency of this proven product has been specifically developed to prevent blockages or restrictions within the boiler or vulnerable system components such as pumps and safety devices.

  • Ideal for reducing pressure loss from sealed systems
  • Seeks out and seals most weeps and leaks
  • Does not cause blockages of pumps, air vents, etc
  • Easily and quickly added via one of the radiators
  • Universal applicator included
  • Patented application
  • Ideal for pressurised systems and combination boilers

Application and Dosage

One pack (290ml) will treat an average sized system (up to ten single radiators) and is added via a radiator. A standard mastic gun is used to dose the Fernox Leak Sealer F4 directly into a radiator air-vent using the special adapter supplied with the product. The entire process can be completed in less than five minutes! In single feed indirect cylinders, e.g. 'Primatic' or similar, potable water chemicals must be used.

Physical Properties

Colour: White
Form: Viscous liquid
Odour: Faint
pH: 5.0 - 7.0
SG: 1.0 @ 20°C

Packaging, Handling and Storage

Fernox Superconcentrate Leak Sealer F4 is supplied in 290 ml cartridges with a universal applicator set. Fernox Superconcentrate Leak Sealer F4 is classified as non-hazardous, but as with all chemicals: Keep out of reach of children. In case of contact with eyes or skin, rinse immediately with plenty of water.

Please contact the supplier to check availability of stock