F4 Leak Sealer Express from Fernox is suitable for use throughout a heating system for sealing small weeps and inaccessible leaks. It works best when you have circulating hot or warm water in the system and it’s usually effective within 1 to 24 hours after use.

Safety devices, pumps and other similar parts will not be blocked while in use.

One 265ml can is suitable for approximately 10 single radiators or an average sized heating system and is added via a filling loop or a radiator.


Features and Benefits:

  • Doses in 30 seconds making this one of the fastest leak sealers on the market.
  • No mess makes this product a breeze to use.
  • Supplied with a filling loop, or alternatively can be added directly into a radiator.
  • No need to drain down your central heating system which saves you money.
  • Seeks out to seal most leaks and weeps.
  • Environmentally friendly formulation in a 100% recyclable can
  • 265ml can
CE Approved

Fernox Central Heating Leak Sealer F4 Express Aerosol 265ml - 58232 Video


Techincal Drawings

£17.33 (Inc. VAT)

7 Available

Fernox Central Heating Leak Sealer F4 Express Aerosol 265ml - 58232 Reviews

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5.0/ 5
1 reviews
  • Lauryn Andrade
    5/ 5

    Follow instructions carefully if using via radiator to avoid a mess on the floor. Make sure rad valves are closed before removing vent and that a valve is open after attaching tube and before injecting the product and closed again before removing the tube. Obvious but worth taking care. After about 4 weeks there is no pressure drop in the system at all. It took a few days to work but it seems to have fixed my problem.