180/280

180/280 insulated chimneys are intended for truly high-power heating appliances. This designation indicates the chimney’s two main dimensions:

180 mm: The chimney’s internal diameter. This is large enough to ensure smooth flue gas removal and strong draft, which is important for larger heating systems.
280 mm: The chimney’s external diameter. This provides sufficient space for a thick and effective insulation layer, which keeps the chimney’s outer surface cool and safe.