The object is to provide a water heater capable of efficiently transmitting radiation heat of a burner to hot water in a hot water storage chamber with improved thermal efficiency. In the water heater, a second restriction part having a shallower depth than a first restriction part is arranged along a peripheral edge of a lower mirror plate of a hot water storage chamber with a protrusion part protruding in a ring shape toward the center side of the lower mirror plate. The protrusion part is further arranged between the first restriction part and the second restriction part, and a burner is positioned so that the burner combustion surface faces the protrusion part.
1. A water heater comprising:
a cylindrical main body;
a hot water storage chamber arranged above a mirror plate that includes an upwardly protruding first restriction part having a first predetermined length in the axial direction of the water heater, wherein the upwardly protruding first restriction part is continuously inwardly tapered towards a center axis of the water heater;
the hot water storage chamber positioned above the mirror plate and in the cylindrical main body;
a combustion chamber having a burner positioned below the mirror plate such that hot water in the hot water storage chamber is heated by combustion of the burner; and
a second restriction part protruding outwardly in a curved ring shape and having a second predetermined length in the axial direction of the water heater that is less than the length of the first restriction part, wherein the second restriction part includes,
a peripheral edge of the minor plate that smoothly merges with and abuts an inside cylindrical surface of the cylindrical main body, and
a protrusion part protruding inwardly in a ring shape toward a center side of the mirror plate, said protrusion part continuously extending between the first restriction part and said peripheral edge;
wherein the burner is positioned such that a combustion surface of the burner directly radially faces said protrusion part and said peripheral edge.
2. The water heater according to claim 1 , wherein:
the burner is an all-primary air burner having a cylindrical burner head, wherein a side surface of the cylindrical burner is said combustion surface;
the burner is arranged so that an upper end edge of the burner head is located above said protrusion part of the mirror plate, and
the side surface of the burner is positioned such that said combustion surface of the burner faces said protrusion part and said peripheral edge.