Water heating system

A water heating system, comprising:

• a heating unit that comprises
• a lead water-heating body configured for heating water in a heating volume,
• at least one inlet for receiving a feed of cold water into said heating volume,
• a hot-water outlet downstream the lead water heating volume for egress of hot water from the heating unit,
• a first two-directional port for allowing water flow into the heating unit upon egress of water through the hot-water outlet and water flow out of the heating unit towards a water container when there is no water flow through the hot-water outlet,
• a second two-directional port for allowing flow of water between a bottom portion of the water container and the heating volume when there is no consumption of hot water, and flow of water between the at least one inlet and the bottom portion of the water container when there is a consumption of hot water through the outlet.

A water heating system, comprising:

• a first heating unit that comprises
• a lead water-heating body configured for heating water in a lead heating volume,
• at least one inlet for receiving a feed of cold water into said lead heating volume,
• a hot-water outlet downstream the lead water heating volume for egress of hot water from the heating unit,
• a two-directional port for allowing water flow into the heating unit upon egress of water through the hot-water outlet and water flow out of the heating unit when there is no water flow through the hot-water outlet;
• wherein the heating unit comprises one or more following heating bodies configured for heating respective one or more following heating volumes downstream the lead heating volume and upstream the hot-water outlet, said one or more following heating bodies are switchable between active and non-active modes, said one or more following heating volumes are connected in to and in fluid communication with the lead heating volume and one another.

A water heating system, comprising:

• a first heating unit that comprises
• a lead water-heating body configured for heating water in a lead heating volume,
• at least one inlet for receiving a feed of cold water into said lead heating volume,
• a hot-water outlet downstream the lead water heating volume for egress of hot water from the heating unit,
• a two-directional port for allowing water flow into the heating unit upon egress of water through the hot-water outlet and water flow out of the heating unit when there is no water flow through the hot-water outlet;
• wherein the heating volume comprises two or more common heating bodies, wherein one of the two or more common heating bodies is said lead water-heating body.