Check Valve, HL4101 #01AD5F

If the small unloader (bleeder) valve on or under your pressure switch leaks constantly AFTER the unit shuts off, replace this part. The check valve is a one-way valve that prevents air from backfeeding from the air tank.

Specifications

NPT - 1/8"  X 27 Port, 3/8" X 18 Port connects to unloader & 3/4" X 14 Tube Port