The APEC ASO is the Auto Shut Off Valve replacement part for APEC reverse osmosis systems — the small but critical valve that automatically shuts off the RO membrane feed when the storage tank reaches full pressure, preventing water waste and protecting the membrane from over-pressure damage. When this valve fails (typical after 5-8 years of operation), the RO system runs continuously to drain — wasting hundreds of gallons of water per month.
Compatible with APEC RO-45, RO-90, RO-PH90, ROES-50, ROES-PH75, and ROES-UV75 model RO systems — the bulk of APEC’s residential RO lineup. 1/4-inch quick-connect fittings make installation tool-free. Light-weight and easy to install or remove during routine RO system maintenance.
For APEC RO system owners experiencing constant drain-line flow (the classic symptom of a failed ASO valve), this small part is the right diagnostic-and-repair purchase. Replacing the valve restores normal RO operation immediately. APEC Water Systems is designed, engineered, and assembled in the USA at their California facility.
