Carryover burners for fluid heating systems and methods thereof

A method for manufacturing a burner unit, the method comprising:

• providing an outer sleeve comprising:
• a first plurality of apertures configured to permit a fuel to pass therethrough at a first flow;
• a second plurality of apertures configured to permit the fuel to pass therethrough at a second flow, the second flow being greater than the first flow;
• providing an inner sleeve comprising a third plurality of apertures and an opening to receive fuel;
• and
• locating the inner sleeve substantially within the outer sleeve.

A water heating system comprising:

• a water tank;
• and
• a heat exchanger comprising a burner unit that includes:
• an ignitor;
• a peripheral duct comprising:
• a transport zone having a first plurality of apertures forming a pathway between the ignitor and a combustion zone, the first plurality of apertures configured to permit a fuel to pass therethrough at a first flow;
• and
• the combustion zone located proximate the transport zone and including a second plurality of apertures, the second plurality of apertures configured to permit the fuel to pass therethrough at a second flow, the second flow being greater than the first flow;
• and
• a central duct located within the peripheral duct, the central duct including a dispersion zone having a third plurality of apertures configured to permit the fuel to pass therethrough.