[QUOTE=rspears;575405]Just curious, why do you drain the tank every night?

Up here in the Pacific Northwest, there is no such thing as moisture free air. Ideally, in a perfect world, your theory is correct: but that has not been my experience. I haven't tried it in a few years, but my old compressor would flood the hose with vaporized water if I left it pressurized. Not as bad in the summer time, but it's so damn wet here 90% of the year that the warm months don't even cross your mind.

It also helps to prevent air leaks due to leaky seals and avoids unnecessary stress on the cylinder reeds. Ideally, the in-tank check valve should be keeping pressure off of the pump heads, once the unloader valve has relieved the pressure in the discharge line after it shuts down. But if the check valve leaks by, and you unplug your compressor when it's not in use (that'd be me) the solenoid doesn't have power to keep the unloader valve open: at least not on mine.

Basically, I've been doing it this way so long that I couldn't break the habit anyhow. Lol