The invention discloses a multi-return gas boiler, comprising a housing, a heating device arranged in the housing, and a
water storage space formed between the heating device and the housing. The shell comprises a water inlet, a
smoke exhaust, and a steam outlet located at the top of the shell. A heat device includes a
combustion chamber dispose at that bottom of the housing, a first cigarette collecting box located above the
combustion chamber, a second cigarette collecting box located between the
combustion chamber and the first cigarette collecting box, a third
smoke collecting box locatedabove the first
smoke collecting box, wherein the
combustion chamber is communicated with the first smoke collecting box through a first pyrotechnic
pipe, the first smoke collecting box is communicated with the second smoke collecting box through a second pyrotechnic
pipe, the second smoke collecting box is communicated with the third smoke collecting box through a third pyrotechnic
pipe, and thethird smoke collecting box is communicated with a smoke exhaust port; The
combustion chamber is provided with a combustion device. The invention has the advantages that the special structural design increases the flow length of the hot smoke, increases the contact area between the hot smoke and the water, makes the
steam generation speed faster, and improves the
heating efficiency of the boiler atthe same time.