Patent ID: 6875961

Claim:
The method of controlling heating of a pool or spa body of liquid, that includes a) operating a pump and a pump motor, for circulating a stream of water to and from the body of water, the motor being an electric motor, b) transferring heat from the motor or from a separate heater, to the stream as it is circulated, c) monitoring the voltage level of electric power to be delivered or being delivered to the motor or heater, d) monitoring the temperature of water in said body of water in the spa or in the stream of water being circulated, e) providing a monitor or monitors operating to effect said monitoring, f) and controlling electrical power delivery to the motor or heater in response to said c) monitoring and/or said d) monitoring, while maintaining electrical power delivery to said monitor or monitors in the event of decrease of power delivery to the motor or heater below a predetermined threshold.