The 2008 models probably still uses the three valve setup...
My three valves are laying on the floor in front of the water heater behind a cabinet door... Maybe someone with your model RV will check in soon...
The three valve bypass does this... Note the oblong shape of the valves tell you if they are open or closed...
I am not a fan of putting the pink stuff through all the pipes etc etc... I drain all of my water from their low water points and blow out the lines with a 12VDc tankless air compressor. Then add some pink stuff to the P-traps... We camp alot off the power grid and usually late into the season. We can do this method anytime we need to and only takes a few miniutes... Then the next morning can just add water back into the tanks and go on...
Always a good idea to learn all you can about your RV Unit before getting caught out in the woods somewhere and not know where things are located...
Roy Ken