Leak sealer CALEFFI C4 (model 570914) — pipe and radiator leak repair compound

CALEFFI C4 leak sealer is a specialist compound formulated to repair small leaks in heating and plumbing systems by being added directly to system water. Intended for maintenance and emergency use in residential and light commercial installations, the product works on pinhole leaks in pipes, joints, radiators and fittings to reduce fluid loss and minimise downtime without requiring immediate disassembly of components.

Advantages

CALEFFI C4 is designed for easy integration into circulating systems and acts without mechanical intervention, enabling temporary or short-term repair of small leaks. The compound is compatible with typical heating system materials and works while the system is in operation, allowing rapid response to minor faults. Its formulation aims to localise and seal leaks at their source, helping to preserve system pressure and reduce the need for urgent component replacement during the initial incident.

Suitable for

• Repairing pinhole and small leaks in central heating pipework
• Sealing leaks at radiator connections and valves
• Temporary repair of leaks in domestic and light commercial plumbing systems
• Maintenance use to limit fluid loss before scheduled service

Key specifications

• Form: liquid additive for system water
• Application method: introduced into circulating system water
• Target leaks: small leaks, pinholes, joints, radiator connections and fittings
• Use case: maintenance and emergency leak reduction
• Compatibility: formulated for use with common heating system materials

How to use

Introduce the recommended quantity of CALEFFI C4 into the system water following the manufacturer’s dosing guidance. Ensure the system is circulating so the compound can reach the leak site; in many cases this means operating the pump and restoring normal temperature and pressure conditions. After addition, monitor the system for signs of reduced leakage and maintain usual safety checks for pressure and temperature. If leaks persist or are extensive, plan for mechanical repair by a qualified technician.

Usage recommendations

Use CALEFFI C4 as a temporary or maintenance measure for small leaks. Do not treat as a permanent replacement for mechanical repair when fittings, joints or components show significant damage. For best results, follow the product dosing instructions and consult system documentation or a heating professional if unsure about compatibility with specific system fluids or materials.