Hi BossMan,
Welcome to the Heartland Owners Forum and to the family. We have a great bunch of folks here with lots of information and all willing to share their knowledge when needed.
You are most likely correct about it being for the water heater, but I'm sure some of our other members with a North Country will jump in soon with better info. You do not want the switch on without water being hooked up and heater full, the element will burn out in just seconds.
Be sure and join our
Heartland Owners Club. Then join us at a rally when you can meet lots of the great folks here and make friends for a lifetime.
Enjoy the forum.
Jim M