Abstract: A whirlpool type hydrotherapy unit includes a centrifugal pump which circulates water in a tub. The pump has a pair of outlets, one of which is a primary outlet immersed in the water to provide a whirlpool effect. A vibrating spray head accessory may be attached to a secondary outlet to provide a water spray and accompanying massage. A large volume of air is induced by aspiration to mix in with the water that discharges into the tub from the primary outlet. The pump is driven by a battery powered D. C. motor which is controlled as to speed and time of operation by solid state controls. Special circuitry also prevents operation of the motor when the battery charger is coupled to an A.C. power supply or when the voltage of the battery falls below a specified value.