1. Introduction
The Fernox 56603 Leak Sealer F4 is a high-performance internal leak sealer designed for use in central heating systems. This product effectively seals small, inaccessible leaks and weeping joints, preventing pressure loss and boiler breakdown. It is compatible with all metals and plastics commonly used in heating systems, including aluminum.
This manual provides essential information for the safe and effective application of Fernox 56603 Leak Sealer.
Image of the Fernox 56603 Leak Sealer F4 500ml bottle.
2. Safety Information
Always read the product label and Safety Data Sheet (SDS) before use. Keep out of reach of children. Avoid contact with skin and eyes. In case of contact, rinse immediately with plenty of water and seek medical advice. Wear appropriate protective clothing, gloves, and eye/face protection. Do not ingest. If swallowed, seek medical advice immediately and show this container or label.
- Storage: Store in a cool, dry place, away from direct sunlight and extreme temperatures.
- Disposal: Dispose of contents/container in accordance with local regulations.
3. Setup and Application
Before applying Fernox Leak Sealer F4, ensure the central heating system is clean. For optimal results, it is recommended to clean the system using a Fernox Cleaner F3 or F5 before applying the leak sealer.
3.1. Dosage
One 500ml bottle of Fernox Leak Sealer F4 is sufficient to treat a typical domestic central heating system of up to 100 liters (approximately 10 radiators) or 100m² of underfloor heating.
3.2. Application Methods
Fernox Leak Sealer F4 can be introduced into the system via a radiator, the filling loop, or the F&E (feed and expansion) tank.
Method A: Via Radiator
- Drain a sufficient amount of water from the system to allow for the addition of the product.
- Locate a suitable radiator, preferably a towel rail or a panel radiator with a removable plug.
- Turn off both radiator valves and loosen the bleed plug or remove the blanking plug.
- Using a suitable injector or funnel, pour the entire contents of the 500ml bottle into the radiator.
- Replace the plug, open the radiator valves, and bleed any trapped air.
Method B: Via Filling Loop (for sealed systems)
- Ensure the system is depressurized.
- Connect a Fernox F-Key or similar injector to the filling loop or a suitable access point.
- Attach the bottle of Leak Sealer F4 to the injector.
- Inject the entire contents into the system.
- Re-pressurize the system to the manufacturer's recommended level.
Method C: Via F&E Tank (for open vented systems)
- Pour the entire contents of the 500ml bottle directly into the F&E tank.
- Ensure the product disperses throughout the system.
4. Operating Instructions
Once the Fernox Leak Sealer F4 has been introduced into the system:
- Circulation: Turn on the central heating system and allow it to circulate normally for at least 1-2 hours. For best results, allow the system to circulate for 24 hours.
- Monitoring: Monitor the system pressure (for sealed systems) or water level (for open vented systems) to observe the sealing process. Small leaks should seal within 1-24 hours of circulation.
- Bleeding: Bleed radiators as necessary to remove any trapped air, ensuring full circulation of the product.
The product is designed to remain permanently in the system to provide ongoing protection against future small leaks.
5. Maintenance
Fernox Leak Sealer F4 is a 'leave-in' product and does not require removal from the system. It provides continuous protection against small leaks. Regular system maintenance, including annual checks and the use of a system inhibitor like Fernox Protector F1, is recommended to maintain system efficiency and longevity.
6. Troubleshooting
- Leak persists after 24 hours: If the leak continues after 24 hours of circulation, the leak may be too large for the product to seal. Professional assessment and repair may be required.
- System blockage: Fernox Leak Sealer F4 is designed not to cause blockages in the system when used as directed. If a blockage occurs, it is likely due to pre-existing sludge or debris in the system, or incorrect application. A system flush with a suitable cleaner may be necessary.
- Product not circulating: Ensure all radiator valves are open and the system pump is functioning correctly. Bleed all radiators to remove airlocks.
7. Specifications
| Brand | Fernox |
| Model Number | 56603 |
| Item Type Name | Leak Sealer |
| Item Form | Liquid |
| Unit Count | 16.907 Fluid Ounces (500ml) |
| Material Type | Silicone |
| Compatible Material | Ceramic (and all common heating system metals/plastics) |
| Surface Recommendation | Pipe, Radiator, Radiant Floor |
| Item Dimensions (L x W x H) | 8.27 x 3.86 x 2.68 inches |
| Water Resistance Level | Water Resistant |
| Included Components | 1 Bottle |
| UPC | 798256172106 |
8. Warranty and Support
Specific warranty information for the Fernox 56603 Leak Sealer is typically provided by the manufacturer or the retailer at the point of purchase. Please refer to your purchase documentation or the official Fernox website for detailed warranty terms and conditions.
For technical support, product inquiries, or further assistance, please contact Fernox customer service directly or visit their official website. Contact details can usually be found on the product packaging or the manufacturer's website.
