Reading the
brochure for your model, I read the 30.1 has an electric portion to the WH, so that begs the question where is that switch on your panel? Could it be one of the two switches below it? Also there are to be tank heaters...
EDIT: Not that any of this pertains to your original question, but any info helps, like what make/model of heater is it?
• Below-Floor Mounted 6-gallon DSI Gas/Electric Water Heater (27.1, 29.2 & 30.1)
• Heated & Enclosed Holding Tanks(27.1, 29. 2 & 3 0 .1)