It is recommended that a ball valve is placed prior to the drain in the circuit to aid on site servicing. Norgren Automatic Drain. A fully automatic drip leg drain for removing liquids from pneumatic/compressed air systems. Manufactured from zinc alloy with a transparent polycarbonate bowl. A G1/8 connection on the bottom of the bowl allows the collected liquids to be piped away and a vent valve allows pressure to be vented easily prior to carrying out maintenance. G1/2" Fitting G1/8" Drain fitting Maximum operating pressure 10bar Accepts ISO 228 (BS 2779) parallel and ISO 7 (BS 21) taper connections