Description
The Caleffi 519700A Differential Pressure By-pass Valve is a precision-engineered brass valve designed to protect hydronic heating and cooling systems by maintaining proportional pump head pressure as zone valves open and close. With 1-1/4″ NPT inlet and outlet connections, this adjustable by-pass valve automatically diverts excess differential pressure to reduce water hammer noise, stabilize flow, and improve overall system efficiency in multi-zone boiler and HVAC applications.
Features & Benefits:
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Model: Caleffi 519700A Differential Pressure By-pass Valve
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Connection Size: 1-1/4″ NPT inlet and outlet
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Adjustable pressure range (approx. 2–10 psi) for precise control
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Maximum working pressure: 150 psi
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Operating temperature up to 230 °F
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Flow capacity up to 45 GPM
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Durable brass body with stainless steel and EPDM internal components
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Reduces water hammer and maintains stable differential pressure in hydronic systems
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Ideal for multi-zone boiler, radiant heat, and HVAC hydronic applications
