Hot tubs, similar to automobiles, are made up of many third party supplied parts. The manufacturers do not actually manufacture every component in the spa, but source them from hopefully reliable vendors. The longer a manufacturer has been in business, the greater the likelihood that the parts being supplied are working for their brand and their customers since otherwise there would be many unhappy customers.
Some of the most widely used hot tub parts include hot tub pumps, blowers, ozonators, circuit boards and entire hot tub spa packs which usually contains an electric heater. A topside control panel controls the electronics below and safety mechanisms are included in the design such as sensors that monitor water temperature and pressure within the heater. A high limit sensor functions to shut the spa off in the case of an overheating condition just as freeze sensors can start the spa up automatically in the case of very low water temperatures.
There are even automatic parts that relate to maintaining water quality such as the spa ozonator and the bromine or chlorine salt systems which produce sanitizer out of salts. Finally, there are also luxury accessories such as radios, led lighting systems and even televisions that are fitted into hot tubs. As these are also third party supplied items, they can also be sourced after-market in the case a replacement part is needed.
Hot tub parts can be found online. Once the hot tub troubleshooting has been completed and a part has been determined to require replacement, simply find the part online and have it shipped! In some cases, online vendors will even ship spa parts free of any shipping or handling costs.