A heating system includes a first pipe portion configured to connect to piping that returns water from a heat exchanger in a building back to a boiler in the building. A longitudinal axis of the first pipe portion can extend vertically. A second pipe portion can have a first end, a second end, and a longitudinal axis extending therebetween. The first end of the second pipe portion can be configured to connect to piping that supplies water to the heat exchanger. The second end of the second pipe portion can be configured to connect to the second end of the first pipe portion. The longitudinal axis of the second pipe portion can extend parallel to the longitudinal axis of the first pipe portion. The second pipe portion can be spaced-apart from the first pipe portion. The system can be in the form of an installation kit for a heating appliance.

The current invention disclose a method and apparatus for production of hot water or steam in a firetube boiler, said method comprising the steps of producing a first flue gas using a first stage of a burner in a first pass of a firetube boiler; passing at least a portion of said first flue gas through a second pass of said boiler, wherein said second pass comprises a plurality of firetubes; routing said portion of said first flue gas to a second stage of said burner to reduce NOx emissions from said second stage of said burner; producing a second flue gas from said second stage of said burner in a third pass of said boiler; passing said second flue gas through a fourth pass of said boiler, wherein said fourth pass comprises a plurality of firetubes.

A downward mobile gasification boiler for surface gas-phase combustion and pyrolysis of biomass briquette is provided. The boiler includes a gasification combustion chamber, a gas combustion chamber, a stranding cage slag remover, a heat exchanger, a water jacket, an air duct and an air distribution system. The air duct connected with the air distribution system is arranged in the inner cavity of the wall surface of the gasification combustion chamber. The gas combustion chamber is arranged at the upper part of the gasification combustion chamber, and an air outlet is arranged in the middle to communicate the gas combustion chamber with the gasification combustion chamber. The lower part of a port of the gasification combustion chamber is provided with a twisting cage slag remover.

A downward mobile gasification boiler for surface gas-phase combustion and pyrolysis of biomass briquette is provided. The boiler includes a gasification combustion chamber, a gas combustion chamber, a stranding cage slag remover, a heat exchanger, a water jacket, an air duct and an air distribution system. The air duct connected with the air distribution system is arranged in the inner cavity of the wall surface of the gasification combustion chamber. The gas combustion chamber is arranged at the upper part of the gasification combustion chamber, and an air outlet is arranged in the middle to communicate the gas combustion chamber with the gasification combustion chamber. The lower part of a port of the gasification combustion chamber is provided with a twisting cage slag remover.