(1). Draining of air tankThe frequency for draining is depended on environment condition and operation time, but usually once every 2-3 days. The way to drain off the condensate is as follows: Put the drain pipe connecting drain valve quick coupling ( See Fig.1-17 ) in a container, with compressed air in the air tank slowly turns counterclockwise the knob on the drain valve to drain off the water in the air tank until all accumulated water comes out from the pipe. After that turn tightly clockwise the knob to ensure no leakage.