Awesome explanation Richard! You should get a job writing the owners' manuals! My owners' manual had pages of installation instructions and a tiny paragraph of operating instructions with no mention of the inside switches. We figured it out after a little trial and error, but I was nervous about it for a few days. I know the same water heaters are used in many different RV brands that have different switch locations (explaining the vague manual for the water heater) but I wish the actual Heartland owners' manual had discussed the water heater switches, or maybe a little sticker inside the main control panel by the switches would be helpful.