+44 (0) 330 100 7750 sales@fernox.com Change Country Leak Sealers Pressure loss within a central heating system is often due to small leaks, weeping joints or pitted pipework produced as a result of internal corrosion within the system. Notoriously difficult to find and seal in inaccessible areas, an internal leak sealer is able seek out and seal microscopic holes effectively. Leak Sealer F4 10L Leak Sealer F4 is an internal leak sealer developed for use in HVAC and light commercial heating and cooling systems to seal small, inaccessible leaks View Product » Leak Sealer F4 500ml Leak Sealer F4 is a internal leak sealer developed for use throughout a central heating system to seal small, inaccessible leaks and weeps which may View Product » Leak Sealer F4 Express 400ml Leak Sealer F4 is a internal leak sealer developed for use throughout a central heating system to seal small, inaccessible leaks and weeps which may View Product » MENU About Us Contact Products BIM Documents USEFUL LINKS Fernox Water Testing Portal Associations & Partners Mobile Apps POLICIES Cookie Policy Privacy Policy Disclaimer Terms & Conditions of Sale Certificate of Conformity Warranty Statement UK Modern Slavery Act Covid-19 Update NEWSLETTER I accept the Fernox terms and conditions, and privacy policy. SUBSCRIBE © Fernox 2021. All rights reserved Cookies To make this site work properly, we sometimes place small data files called cookies on your device. Most big websites do this too. Accept