Water heater venting system and components thereof all made of plastic comprised of a vent kit body, a concentric vent pipe and a rain cap; pipe fittings and vent pipe, all made of plastic for ventilation applications; rain cap made of plastic; concentric ventilation pipe made of plastic; flue gas ventilation kit for venting tankless water heaters and components thereof, all made of plastic comprised of a plastic exhaust pipe, a fresh air intake pipe, a rain cap, and a ventilation kit body co...