Draining Custom Loop

[jpp354]

I am trying to drain a custom cooling loop but even with a ball valve I end up with a substantial amount of water left in the loop. The loop is made up entirely of PETG tubing and metal components, would there be a problem with removing one of the empty tubes and using an extremely weak air compressor or hand pump to blow out the rest of the water?

 

[grimfox]

Open a fitting at the top of the loop and see if that helps to drain. I've had similar issues with my loop I didn't plan on draining the loop when I built it at first and now I've been trying to modify it since to make it more serviceable. Flex tubing makes it lots easier.