Is it better to leave air in the receiver (pressure tank) or to drain the pressure to zero nightly as a part of shutting down the shop?

Hello,
I've never heard of "draining" a tank. But, I'd be sure to shut the power off, to the compressor, before I'd leave the shop for any lenght of time, other wise you might come back to a burst line and a burned up compressor!

It goes without saying that the electricity is off when the shop is closed. Water or condensation in the tank should be kept to a minimum by regular checks and removal, and is maintance.

My question was in reference to leaving the tank pressurized or bleeding the pressure down to zero on a daily basis.

We have two big compressors at work and we never empty the tanks, just bleed off the condensation .

You can leave the tank charged, its inefficient to empty the air and refill every day. You would get more condensation if drained the air daily, just drain the moisture once in a while.

Most are designed to hold pressure so air will always be available on demand. Mine stays plugged in and on all the time - it will occasionally run during the day or night, even when not in use. It shouldn't run away and burn up unless something is wrong - as 'frogvalley' said, it's inefficient to empty and drain it every day unless you are only using it once or twice a year.

I just drain the water out once or twice a week, Of course its sort of humid here in Iowa. I also un-plug the compressor when I close up.

The one time I do drain the tank completely is in very cold weather. Water in the tank freezing isn't good for it, and starting the motor under load while it is cold isn't good for it I seem to remember reading somewhere... Especially when the weather is cold enough to effect the lubrication on the compressor, so unless you are heating your shop around the compressor or are using special lubricatants designed for colder temps (when I talked to the engineers over at Quincy they said they made a special oil for low temp installations...) I have gotten into the habit of draining it Just to get the mositure out of the tank, and if your compressor has been sucking coal smoke I would be pretty diligent about keeping it drained, I might also check the ph of the water if I thought it was sucking too much coal smoke... Good Compressor are expensive I try to take care fo mine the best I know how:-) Not that I know that much;-)

My compressor gets used 365 days of the year. I drain it daily and also try and keep the moisture trap clean each time I use it. I have a ball valve at the outlet before the first trap. This is the on/off I use. Power stays on. Only way I can have a FUBAR is for this ball to malfunction (or a bad pressure switch). This compressor is about 8 years old. I changed the oil in it about monthly for the first year of it's life and I now change it couple times a year. 30w MM Phillips oil. Good oil changed frequently I suspect is the lifeblood of any mechanized thing. They make cartrige filters for the air inlets. I DO need to spend the money on a better moisture trap but for now, I continue to drain the one at the compressor, the drip tee downline and the trap on the back of the plasma. Suspect that the welds in the pressure tank should be kept under pressure at all times. My humble opinion.