Caleffi Differential Pressure Bypass Valve NPT

The Caleffi Differential Pressure Bypass Valve (also called a differential by-pass valve or hydronic bypass valve) is part of the Caleffi 519 Series. It is built for hydronic heating systems that use a fixed-speed circulator to feed several zones controlled by two-way zone valves. The valve connects the supply and return lines. It lets flow recirculate in proportion to the number of zone valves that have closed.

Key Features:

• Limits pump differential pressure: As zone valves close, the valve bypasses the excess pressure. This helps prevent water hammer and flow noise.
• Adjustable setting: A graduated scale and knob let you set the bypass pressure. The adjustment range is 2 to 10 psi.
• Brass body: The durable brass construction suits hydronic heating and cooling circuits.
• EPDM seals: EPDM O-rings are used for sealing.
• NPT threaded connections: Threaded NPT connections allow conventional installation. Some versions of the 519 Series also offer sweat union outlets.
• Rated for demanding service: Maximum working pressure is 150 psi. Maximum working temperature is 230°F. It is intended for water and glycol solutions.

Caleffi is a well-known maker of hydronic and plumbing components. This valve helps protect circulators, zone valves and piping from excess differential pressure. It is a good fit for zoned radiant and baseboard heating systems. Choose the connection configuration and size that match your piping.