Abstract: A UV light and socket assembly having a pin and hole arrangement with a central pin and corresponding hole with peripheral pins and corresponding holes arranged approximately 120 degrees from each other from the central pin and opening. The light and socket assembly including a locating projection and corresponding locating opening that receives the projection that is positioned so as to be aligned with one of the peripheral pin and openings and the central pin and opening.

Abstract: A UV light and socket assembly having a pin and hole arrangement with a central pin and corresponding hole with peripheral pins and corresponding holes arranged approximately 120 degrees from each other from the central pin and opening. The light and socket assembly including a locating projection and corresponding locating opening that receives the projection that is positioned so as to be aligned with one of the peripheral pin and openings and the central pin and opening.

Abstract: A spa or hot tub system includes a tub forming a cavity that holds a fluid such as water therein, and a water circulation system provides for circulation of water within the tub. The hot tub includes inner and outer surfaces, and defines an internal space. A heat pump system is operably connected to the water circulation system, and heats the water in the hot tub. The water side heat exchangers of the heat pump may include a polymer housing, and coiled inner elements for refrigerant. The coils may be made of a corrosion-resistant metal tubing or the like. The system may include a conventional electric heating element in addition to the heat pump to provide additional heating capacity.