Swimming pool and spa pumps
Swimming pools and spas have pumps for two typical uses. The main swimming pool pump sucks water in from either the main drain, the skimmers, a dedicated vacuum port or a wall suction port. It the brings the water through the pump followed by the filter. After the swimming pool water is filtered the pump pushes it through the heater, salt water generator(if installed) and then back to the pool via the return lines and ports. Spa pumps can be used to provide back and calf jets or for circulation through the filters and heater. Most spas have in floor suction which provides enough water to run through the heater and return via these back ports. You may also have an additional pump that is solely used to provide jets for larger spas.
Swimming pool heaters
Swimming pool heaters can be either gas, electric, or solar.
Gas heater- this is the most common type of heater. Water is brought to the heater via the electric swimming pool pump and ran over a heat exchanger. This heat exchanger is heated by gas flame similar to how a hot water heater works. The water is then returned to the swimming pool via the returns. This cycle is repeated until enough of the water has been heated to bring the total temperature of the swimming pool up to the desired levels.
Solar heater-solar swimming pool heaters are a collection of heat exchanges that are either mounted on a roof or in an area of a yard that allow enough space for the sun to heat the water. The water passes through this exchanges and the sun heats it up. It is then returned to the swimming pool and is able to slowly heat the water.
Swimming pool coolers
Salt water generators