IT would help to know WHAT you are replacing......A Suburban or Atwood water heater.
Nautilus wiring
Black (-)12VDC
Red (+) 12VDC
Blue and Orange - For a lamp connection
White - 2 white lines for the On Demand Control Center
RV wires.....
The Black/White/Copper are 120V AC wires and NOT USED. Nautilus is all 12V DC ONLY
Open the 120V AC Circuit Breaker for water heater (electric element)...MARK it and wire nut/tape off those wires.
Need Old water heater brand/model....???
Here is the wiring diagram for the Nautilus (which should be with installation instructions)
Nautilus Service/Training Manual
