• Fernox F4 Leak Sealer
• 500ml
• Ideal for reducing pressure loss from sealed systems
• Seals most weeps and small inaccessible leaks
• Saves time and money on draining down and repairing
• Does not cause blockages of pump, air vents etc
• Compatible with all metals and materials commonly used in central heating systems

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.