I have an Atwood water heater with both electric and engine heating (apparently). The water heater will be replaced sobIm fully bypassing it. I connected the red to blue, cold water feeds the hot water lines now. How are the two engine lines affected? Ive disconnected them but dont know what water is in there? Is it from the water heater that flows by the engine to heat or is it engine water that flows through the water heater casing? Should I just tie the two together to create a loop outside of the heater and isolate the engine? If so can I run the engines like that until I replace the heater? The two black hoses are in the pic and disconnected. Thanks!