Another bypass valve question.

I have a 2017 R178. I have owned it a couple of months and thought I had the by-pass valve for the hot water heater figured out. However I noticed yesterday that I previously hadn't looked close enough at my set up. I discovered a 3rd valve I somehow missed in my earlier inspections. And I was told that my unit may have 2 valves or 3 valves. Previously I only noticed 2 valves, one for the hot water side and one for the cold water side of the hot water tank. I didn't see a valve that you would expect for the by-pass valve located in a link between  the hot and cold water hoses. However yesterday I noticed a valve I hadn't noticed before (don't ask me how I could possibly miss it). The 3rd valve really has me perplexed. I assume it almost has to be a by-pass valve for the hot water heater but it is not a valve between the hot and cold water hoses leading to the hot water heater. This valve appears to come off the water pump and the hose from the valve goes into the floor near the fresh water tank. I am really at a loss for what valve this is and where it should be set if it is not the by-pass valve?

Originally posted by StephenH That is a winterizing valve for the water system. It allows one to change to pulling RV antifreeze in through the stub hose and pump it through the system. It has nothing to do with the hot water tank. When we first got our 179, it was set to the winterizing position. I had a time trying to figure out why the water pump was not drawing water from the tank. I finally found the valve and changed it over and all was well. I don't recall this being covered in the dealer walk-through. It is not readily visible without removing the bed platform in the 179, so it was easy for it to be skipped.