After a bit of searching, found exactly what I need: automatic drain valve , $2.35 each. smile

This should work for air, but I'm not 100% certain...only one way to find out! Maybe a small pressure reducer so that 150psi doesn't blow this out, but should be OK. Whatcha think?

As soon as the compressor leaks down to 4psi, the system drains itself. Perfect!

-Boyo

'48 Willys CJ-2A / '55.1 Chevy 3600 / '66 Austin-Healey 3000 / '04 Volvo wagon (parenthood!?)