What are Boiler Flues?
A boiler flue is a duct, pipe, or chimney that is used for conveying exhaust gases from a fireplace, furnace, boiler, or generator to the outdoors. In other countries like the United States, they are also known as vents. For combi boilers they are known as breaching for water heaters and modern furnaces. The flue boiler is usually operated by buoyancy which is also known as the stack effect, or the combustion products that may be persuaded via a blower. Because combustion products contain carbon monoxide and other dangerous compounds, the proper draft, and admission of replacement air is important. Thus, flue boiler is used to ensure that the combi boilers are working efficiently.
Single or Twin-Wall Flue
While many producers promote single-walled boiler flues for condensing boilers, certain factors must be taken into great consideration. The combi boiler must only ever work in condensing mode to maintain safe external temperatures on the flue boilers. However, single-wall flues are generally accepted as being the correct choice for condensing boilers with long external runs and where condensation freezing in winter could be an issue. Therefore, it is not incorrect to install a twin-walled flue.
Plastic Flue and Its Functions
Because condenser boilers have low flue-gas temperatures, manufactures can use plastic boiler flues for some applications. Boilers such as Hamworthy’s Milborne condensing wall-hung range can safely work with a polypropylene flue. These types of boilers have a flue-gas temperature of 55°C when condensing at 50°C this enables them to use a Class B1 fire rated 50 mm polypropylene flue system with a flue run of up to 30 m. Plastic flue headers are said to connect up to three Milborne 502 boilers using 50 mm-diameter pipes into a single 125 mm-diameter flue for exiting the plant room. These plastic components of the flue boilers also assimilate a silicone ring seal to guarantee simple push-fit watertight joints.