I noticed on a newer Blue Bird school bus driving around the other day the words "Drain Daily" as a sticker on the front.
Recently after doing research on Air Brakes and Semi Trucks I've learned about draining the tanks. There are 4 valves: Primary, Secondary, Wet, Accessory.
We just toss the 4 valves open and release all the air until there's no more hissing, a good little bit of moisture lands on the ground. Seems Good!
Just thought I'd share this as we went months on end without draining our tanks when we first bought our bus. . . Hoping no damage has been done!
From what I hear some busses have automatic drain valves? I have no idea how to check if ours does or doesn't though, I'm just going to assume it doesn't and keep draining after each use!