I have one valve that is attached to the frame - I was told this is the fresh water tank drain.
I have two valves under the outdoor kitchen - I was told these are low point drains for the kitchen hot/cold.
I haven't had warm enough weather to dewinterize yet, so I'm going off what they told me.
2016 Jayco Eagle HT 29.5BHDS (ordered 12/30/15, delivered 3/8/16)
2015 F-350 crew cab, short bed, 6.7L PSD, Pullrite Superglide 3300 hitch