Fernox leak sealer F4 liquid is ideal for reducing pressure loss from sealed systems. Seals most weep and small inaccessible leaks. Saves time and money on draining down and repairing. Does not cause blockages of the pump, air vents etc. Compatible with all metals and materials commonly used in central heating systems.

• Volume: 500ml.
• Plugs small internal weeps and leaks in central heating systems
• Ideal for reducing pressure loss from sealed systems
• Saves time and money on draining down and repairing
• Treats 100L system or up to 10 single radiators
• Compatible with all metals and materials commonly used in central heating systems