Johnson Controls A-4000-138 Station Refrigerant and non-corrosive gases typically found

and non-corrosive gases typically found in HVAC and industrial process loops

While optimized for 110/120V AC coils

and check the 80V HSI for continuity

What causes a humming or chattering noise during operation

Johnson Controls A-4000-138 Station Refrigerant and non-corrosive gases typically foundThe Johnson Controls A 4000 138 is a professional grade remote mounted pressure reducing station engineered to maintain precise pneumatic control system performance. This unit effectively regulates output pressure within a tight 0. 02 psi tolerance, even when managing input pressure variations of up to 20 psi. Designed for rigorous HVACR environments, it handles a maximum input pressure limit of 300 psig and provides a reliable air flow capacity of 25