Years ago I worked for a company that built a new shop. The air compressor was installed over a small "room" double entry to stop cold air entry in the winter. The air outlet from the tank had a loop up to stop any moisture getting into the shop air lines. After a while I noticed the compressor would cut in almost immediately. So I mentioned that I thought the compressor needed to be drained. Response was the loop stopped the water, to which I replied "where does the water go?"