A spot which has all kinds of good ways to look at lots of the parts on an interactive site is here for your specific RV:
This does not give much info on how/ where to get to those parts but it may help to know they are there?
It shows you have two types of check valves with one on each line, in/out!
Click these snips to get a better view or go direct to the parts drawing?
This will also let you find an item in the PDF style list at right if you know the name and when you click it there, it will light that item in yellow to help spot it on the drawings.
Works the same in reverse if you click item on drawings, it highlights that on the parts list.
One way to get the "real" name of parts I find that I don't know!
The question of drain or not may depend on how you use the RV.
We do not go often but the RV may set for several weeks between trips, leaving any water with the remaining bacteria to get warm and let that bacteria multiply hundreds of times.
So how we use that water can also matter. If we use the water for cooking rinsing food, etc. after it sets for several weeks, there is a good chance we are raising our chances for illness from the polluted water.
Things like rinsing pasta come to mind!
We just feel it worth the time to open the drain and get away from any questions of being safe to use it any way we need. But I also add a small valve to open rather than pulling the big awkward plugs as I do for winter.
Point to keep in mind is the level of water treament is set to cover the normal bacteria public water, not enough to kill ALL bacteria but just enough to get it down to safe to drink for most people.
Even bottled water has expiration dates due to the bacteria growing over time, even in the closed bottles.