A spa control system designed to reduce maintenance cost by providing modular construction for major control functions, with built-in diagnostic capabilities for isolating defective spa components. Multi-colored LEDs on the spaside panel constantly report the status of each component of the spa as well as the status of the functional modules themselves. Each time a component is activated, measurements of operational parameters, such as load currents, are instantly made and evaluated so that the proper LED color can be presented at the spaside. Since major functions such as audio, LED control, wireless, and spa logic are separated into removable modules, repair of the control system requires less time and less skilled personnel. Other design improvements, such as direct monitoring of heater element temperature and the purging of pumps on an as required-basis, enhance the spa's overall reliability and thus reduce the need for maintenance.