How to repair system leaks

Leaks in water systems can result from external frost damage, dry solder joints, accidental perforation during maintenance or decoration, or internal corrosion.

Sealing internal leaks (central heating systems only)
Small leaks, including pressure drops on combination boilers and other sealed systems, can be repaired using Fernox Leak Sealer F4. Each Leak Sealer F4 product treats 100 litres or up to 10 single radiators.

On an open vented system, pour the Leak Sealer F4 into the tank and simply draw off 5-10 litres of water from the drain cock initially returning this to the header tank to ensure that no treated water is thrown away. Repeat the previous step until all Leak Sealer F4 has been absorbed into the circulating system.

Switch on the circulating pump and apply at least a small amount of heat to achieve even distribution.

An alternative solution for dosing is to inject Fernox Leak Sealer F4 Express or Fernox Superconcentrate Leak Sealer F4 directly into the radiator via the bleed valve.

Repairing external leaks (to all types of water pipes)
To repair leaking external pipes and fittings, use Fernox LS-X External Leak Sealer with a bandage of PTFE tape or another suitable reinforcement tape.

After turning off the water and draining down to remove water pressure from the leak, apply Fernox LS-X External Leak Sealer to a dry surface around the area of leakage. Wrap the pipe with a layer of PTFE tape or other reinforcement tape with 50% overlap and extend well beyond the area of the leak.

Immediately apply repeat coats of Fernox LS-X External Leak Sealer and further layers of bandage to form a repair about 5mm in total thickness before allowing to cure.

Share:

More posts:

How to descale a hot water system manually

The damaging effects that limescale can have on the lifespan of a boiler and the energy efficiency of a central heating system are significant. Part L of the Building Regulations stipulates that where mains hard water exceeds 200 ppm, feed water to water heaters and the hot water circuit of combination boilers must have a scale reducing device fitted. Why

Read More »

Why do I need to test system water?

A core requirement under BS 7593:2019 is that central heating systems are tested annually, to help maintain system health and to identify and rectify any issues before they cause damage to the system. The Benchmark Commissioning Checklist further supports this practice to evidence the correct servicing and installation of boilers. The onsite Express Inhibitor Test makes compliance with these industry

Read More »

Country