[C320-list] Hot Water Heater Cold Water Line - Check Valve

[Paul Rickman]

A few days ago, I put out a question about the Whale Quick Connect fitting and a back flow preventor
on the cold water line right next to the hot water heater. I didn't get any answer. So lets try this:

Does the cold water line require a "check valve"? Will a check valve prevent the hot water from flowing
back into the cold water line? Does anyone know what people use for a check valve, if any, in the cold water
line? Check valve = back flow preventor. 

I'm going out to some of my local boat supply stores tomorrow to check on plumbing supplies.

Thanks,
Paul
Affinity 657
Baby Bridge Marina