Chimney tee DN 180/250, 90° double-wall for boilers with open combustion chamber SDBT90180250

Double-wall chimney tee DN 180/250 – 90 degrees

The key element in constructing a modern flue gas exhaust system is the material used for the duct. In the case of gas and oil boilers with an open combustion chamber, condensates formed during operation are highly acidic. Standard stainless steel may not withstand this environment in the long term. Therefore, this chimney tee is manufactured from acid-resistant sheet metal, which constitutes its main advantage over standard solutions. The core sheet thickness is 0.8 mm, ensuring adequate structural rigidity and resistance to chemical corrosion.

The double-wall system allows for the installation of an independent flue duct without the need to utilize existing masonry channels. This enables installation both inside the building and on the external facade. The space between the inner and outer jackets is filled with 30 mm thick mineral wool. This insulation serves a dual function: it maintains high flue gas temperatures (preventing rapid cooling and the formation of additional condensate) and protects the surroundings from the high temperature of the pipe. Consequently, this component can be mounted directly against walls or other building materials without risk of thermal damage.

Application and Technical Characteristics

This component is used to change the direction of flue gas flow by 90 degrees and to connect an additional heat source or ventilation at a single point (tee function). It is dedicated to devices with a nominal diameter DN 180 (core) and an outer jacket dimension of DN 250.

The interior of the pipe is made of acid-resistant steel alloy 1.4521, which effectively resists the action of acidic condensates formed during the combustion of gas and oil. The outer casing is made of stainless steel (alloy 1.4509), providing aesthetics and mechanical protection for the insulation. Between these layers lies 30 mm thick mineral wool, which effectively reduces heat loss and protects against burns in case of accidental contact with the pipe. The entire assembly is characterized by resistance to soot fires, increasing installation safety in the event of a sudden temperature rise in the duct. Connections are made using a bell-and-spigot system, which facilitates quick installation and ensures tightness without the need for additional gaskets or adhesives at each component.

Parameters such as the deflection angle of 90 degrees and nominal diameters DN 180/250 define the precise scope of application for this component in gas and oil installations with an open combustion chamber. CE certificates of conformity confirm compliance with EU requirements for construction products, which is crucial during the acceptance of the installation by a supervising inspector or chimney sweep checking the continuity of the ventilation and flue gas system.

Installation and Operating Conditions

Installation of double-wall system components is simple thanks to the use of bell-and-spigot connections. The installer inserts one component into another, which automatically centers the pipe and creates a tight mechanical joint. Such a construction eliminates the risk of leaks resulting from inaccurate fitting or errors in soldered or riveted seams, which occur in older single-wall systems.

It is worth remembering that although thermal insulation allows for mounting against a wall, one must always maintain the minimum distances required by the boiler manufacturer's instructions and occupational health and safety regulations regarding gas and oil installations. Acid resistance ensures that this tee will perform well even in installations operating under heavy load or with low boiler efficiency, where the amount of condensate is higher than standard.