A: It's more convenient to connect the drain valve to the outside for drainage; otherwise, you need to turn the drain valve at the bottom of the air tank to drain the water. Without the drain valve connected, it's located below the air tank, requiring the machine to be lifted to turn it, which is inconvenient. When connecting the extension hose, the drain valve is usually moved to a more easily accessible position. If not needed, it can remain below the original air tank location.Example of a drain valve modified to drain outside the pipe (HOSE):

A valve must be installed on the pipe. The valve should only be opened when drainage is needed; otherwise, air will continue to leak. Therefore, an automatic drain can be installed to drain water on a regular schedule. The drain should be automatic every day, with a timer set to open and close at fixed times.