Waterway structure and water heater

A waterway structure, comprising:

• an inlet pipe;
• and
• a flow regulating valve having a first water inlet and a first water outlet, the first water inlet being connected to the inlet pipe;
• and
• an on-off valve having a second water inlet and a second water outlet arranged opposite to each other, the second water inlet and the second water outlet being fluidly aligned to establish a continuous flow path along a preset water flow direction, and the second water inlet being connected to the first water outlet, and the second water outlet is configured to be connected to a heating assembly;
• and
• a transition valve core rotatably disposed in a valve cavity of the on-off valve about a predetermined axis, the predetermined axis being perpendicular to the preset water flow direction;
• the transition valve core is provided with a water flow passage extending therethrough along a flow direction, the flow direction being perpendicular to the predetermined axis;
• wherein, when the on-off valve is in a closed state, the valve cavity is isolated from an upstream flow passage of the on-off valve, and the transition valve core is positioned at a first angular position relative to the on-off valve such that the flow direction is perpendicular to the preset water flow direction;
• and
• when the on-off valve is in an open state, the valve cavity is communicated with the upstream flow passage of the on-off valve, and the transition valve core rotates relative to the on-off valve in a self-adjusting direction under an impact force of the water flow entering the valve cavity to a second angular position, thereby aligning the water flow passage with both the second water inlet and the second water outlet.