Removing the old gasket and clean the boiler casing and cover plate jointing surfaces.
do not use any grease, adhesives or jointing compounds
Ensure the gasket is the correct size for the cover plate.
Keep cover plate central within the aperture and tighten the crab clamp bolt. Tighten it only sufficiently to avoid leakage, this is vital to avoid overload of the rubber gasket when the boiler pressure is achieved.
Maintain light tension on bold during the service period (normally 12 months)