De Dietrich 94320214 silicone filler Novasil S17

This is a De Dietrich silicone filler sold under the reference Novasil S17. It is listed under the boiler housing parts category, a group that includes panels, doors, brackets and sealants. Parts of this type are applied to joints and seams in the boiler casing, between access panels or around the combustion chamber door. Their function is to provide a flexible, heat‑resistant seal that prevents flue gas leakage and helps retain heat within the appliance. Such silicone fillers are selected primarily for their ability to withstand the temperature cycling that occurs in a boiler. The material must remain elastic after curing to accommodate thermal expansion of the metal panels without cracking. When replacing an existing sealant, the old residue must be removed thoroughly from the mating surfaces; any remaining hardened filler can prevent a proper seal. The new filler is applied in a continuous bead, and the joint should be closed before the silicone skins over. Because the filler bonds to the housing parts, it is specific to the geometry of the joint rather than to the boiler model itself – but a service technician should verify that the product is intended for the temperature range and exposure conditions of the appliance being repaired. No technical ratings, dimensions or application instructions beyond the manufacturer’s labelling have been provided for this particular article.