Today, probably almost every house has heating gas boilers. Gas boilers are very diverse: someone has atmospheric boilers, and someone has turbocharged, that is, boilers with a closed combustion chamber. But all these boilers are united by the fact that in each of them a chimney should be installed. The chimney for gas boilers can also be the most different. For example, there are chimneys that have a round, rectangular or oval pipe. This type of chimney is used for gas boilers with an open combustion chamber. There are coaxial chimneys of a different cross -section, which should be used in boilers with a closed combustion chamber. In some boilers there are chimneys that has plastic pipes. This type of chimneys is used in boilers, outgoing gases of which have a very low temperature.