A diverter/mixing valve comprising: a main outer housing having a first inlet port , a second inlet port , an outlet port , and an inner support having a frustoconical shape, a first end connected to the first inlet port of the main housing that forms a channel disposed around an inner perimeter of the first end of the main housing , a second end distally located from the first end , a side surface that extends circumferentially from the first end to the second end , and inlet openings defined in opposite sides of the side surface ; a barrel assembly rotatably disposed inside the main housing , the barrel assembly including an inner sleeve having inner flow openings defined therein and an outer sleeve having outer flow openings defined therein, the inner sleeve having a conical shape and includes a first end slidably disposed in the channel , a second end distally located from the first end , a side surface circumferentially extending from the first end to the second end , and inner flow openings defined in opposite sides of the side surface , the inner sleeve mating with the inner support of the main housing when the barrel assembly is inserted into the main housing ; and an actuation device rotatably connected to the inner sleeve of the barrel assembly , the actuation device rotating the barrel assembly between an open end inlet position where a first fluid stream flows into the first inlet port , through the inner sleeve , and out the outlet port and a second fluid stream (SFS) is blocked from flowing into the second inlet port , and an open side inlet position where the second fluid stream (SFS) flows into the second inlet port , through the outer sleeve , and out the outlet port and the first fluid stream (FFS) is blocked from flowing into the first inlet port . a main outer housing having a first inlet port , a second inlet port , an outlet port , and an inner support having a frustoconical shape, a first end connected to the first inlet port of the main housing that forms a channel disposed around an inner perimeter of the first end of the main housing , a second end distally located from the first end , a side surface that extends circumferentially from the first end to the second end , and inlet openings defined in opposite sides of the side surface ; a barrel assembly rotatably disposed inside the main housing , the barrel assembly including an inner sleeve having inner flow openings defined therein and an outer sleeve having outer flow openings defined therein, the inner sleeve having a conical shape and includes a first end slidably disposed in the channel , a second end distally located from the first end , a side surface circumferentially extending from the first end to the second end , and inner flow openings defined in opposite sides of the side surface , the inner sleeve mating with the inner support of the main housing when the barrel assembly is inserted into the main housing ; and an actuation device rotatably connected to the inner sleeve of the barrel assembly , the actuation device rotating the barrel assembly between an open end inlet position where a first fluid stream flows into the first inlet port , through the inner sleeve , and out the outlet port and a second fluid stream (SFS) is blocked from flowing into the second inlet port , and an open side inlet position where the second fluid stream (SFS) flows into the second inlet port , through the outer sleeve , and out the outlet port and the first fluid stream (FFS) is blocked from flowing into the first inlet port . <EOS>