Mr. Steam CU-HTC High Limit Control for Commercial GeneratorsMr. Steam CU HTC High Limit Control for Commercial Generators The CU High Limit Device is for use with any CT Day Spa or CU Commercial Steam Generator System to provide over temperature shutoff and alarm function. If the steam room temperature rises above the set point of 120F, the device will sound an alarm and disconnect the heating source. The Device and the steam generator can only be reset by the attendant after the steam room cools to a point