Caleffi 519599A Differential Pressure Bypass Valve 3/4" Sweat Union, Adjustable 2-10 PSI

The Caleffi 519599A is a 3/4" differential pressure bypass valve with 3/4" sweat union connections, used to maintain minimum flow and limit differential pressure in hydronic systems with zone valves.

Installed between supply and return, the valve opens as zone valves close and system differential pressure rises, bypassing flow to protect the circulator and boiler and to reduce flow noise in the zones that remain open. The opening setpoint is adjustable from 2 to 10 psi, and the valve has an angle body pattern.

Before ordering: Confirm the 3/4" sweat union connections suit your piping layout. Set the valve based on the circulator curve and system design; the setting procedure is in the installation manual below.

Specifications

• Brand: Caleffi
• Manufacturer Part #: 519599A
• Series: 519 series differential bypass valve
• Type: Differential pressure bypass valve
• Size: 3/4"
• Connection: 3/4" sweat union
• Body Pattern: Angle
• Material: Brass
• Setting Range: 2 to 10 psi
• Max Pressure: 150 psi
• Max Temperature: 230°F
• UPC: 8016615274745
• Category: Balancing Valves

Documents

• Technical Data Sheet (PDF)
• Installation & Operation Manual (PDF)
• Submittal Sheet (PDF)
• Product Brochure (PDF)

See also: balancing valves, all Caleffi products.