Method of installation and manufacturing of a stack pipe heat exchanger with integral connectors

A method of installing a drain water heat recovery exchanger for pre-heating water to be heated using a solar, electric or combustion energy hot water heater or to be sent to the cold-water line of a hot-water-consuming apparatus, the method comprising:

• providing a drain water heat recovery exchanger including:
• a copper pipe with an integral copper pipe fitting with a diameter that is smaller than a non-fitting portion of said copper pipe of said drain water heat recovery exchanger and an integral copper pipe outlet fitting with a diameter that is smaller than said non-fitting portion of said copper pipe of said drain water heat recovery exchanger, wherein each of said fittings is fashioned from said copper pipe of said drain water heat recovery exchanger by at least one of rotary-forming, roll-forming, crimping and die-pressing said copper pipe to include barbs for a male plastic pipe connection;
• and
• a core waste water drain tube;
• cutting out a portion of a vertical drain water pipe of a building;
• inserting said drain water heat recovery exchanger into said drain water pipe at a position of said cut-out portion of said drain water pipe;
• connecting said core waste water drain tube to said drain water pipe;
• and
• selecting additional copper pipes or cross-linked polyethylene pipes for connecting to said fittings, and
• when said cross-linked polyethylene pipes are selected, connecting a first one of said fittings to a cold-water supply using a first cross-linked polyethylene pipe of said cross-linked polyethylene pipes, and connecting a second one of said fittings to an inlet of a hot water heater, a hot water tank or a cold-water line of a hot-water-consuming apparatus using a second cross-linked polyethylene pipe of said cross-linked polyethylene pipes by making a bend in a length of said second cross-linked polyethylene pipe between said second one of said fittings and said inlet of said hot water heater, said hot water tank or said cold-water line of said hot-water-consuming apparatus;
• and
• when said additional copper pipes are selected, cutting said fittings to remove a portion of said copper pipe including said barbs, soldering a copper pipe fitting to each end of said copper pipe of said drain water heat recovery exchanger, and connecting a first additional copper pipe of said additional copper pipes and a second additional copper pipe of said additional copper pipes to respectively each of said copper pipe fittings, wherein said first additional copper pipe is connected or connectable to a cold-water supply and said second additional copper pipe is connected or connectable to an inlet of a hot water heater, a hot water tank or a cold-water line of a hot-water-consuming apparatus.