Abstract: A circulating bath (10) including a heater (18) configured to heat a fluid (34) in a reservoir (22). The heater (18) is configured to be operatively connected to a source of power (50) by a control circuit (39) operatively coupled to the heater (18). First and second fluid level sensors (14) (16) are operatively coupled to the control circuit (39), and provide signals indicative of a low fluid condition in the reservoir (22). The control circuit (39) is configured to receive the signals from the fluid level sensors (14) (16), and disconnect the heater (18) from the source of power (50) in response to receiving a signal from either of the first and second fluid level sensors (14), (16) indicative of a low fluid condition.