Plus get rid of the oiler, especially if you ever want to use your air lines for painting.  In fact, all your air lines after the oiler are now ruined for painting from what I've read over on GJ.

Agree on ditching oiler. Water/oil separator, dryer is good. Need a drop with ball valve to drain condensed water.

Run your lines in copper. Fun to work with and helps condense water vapor before it reaches the separator. And it won't fail like pvc.

My old house...
Attached File

Agree.  Copper is fun.  Not that expensive.  If you can't sweat pipe, call up a friend/neighbor and offer them beer.  

I used a QD type screw coupler where my filter/reg attaches.  I had a reg go bad and it was easy to remove the assembly for replacement without being stuck up against a wall.

Mo bettah than copper and tons easier to install:



https://www.northerntool.com/shop/tools/product_200484023_200484023

He went up, over, got slope, got a drain, t'd off the top to drop down...and then went into the separator. Someone was paying attention.

That is another dryer/regulator combo.  I don't have that style personally, but I think it may have a filter inside.  I could be wrong.  

Realistically, if you are adding a dryer/regulator at each line drop you will be fine with Harbor Freight stuff unless you do a lot of sandblasting and painting.  Those jobs require very dry air.  

My personal setup has a water drop at every outlet.  I have a dryer going into the system, then I have a second dryer at my hose reel I use for painting and sandblasting.  I also use one of those small round "last chance" filters at my paint gun when I'm painting.  Even with the water drops and 2 dryers I still get moisture in my air lines from time to time.