The GV310R-50B35 is a 3-way mixing globe valve from the VG310R series, sized for DN50 pipe with Rp internal threads. Bronze body, PN16 pressure class, and a 35 kvs flow coefficient — that kvs figure tells you the flow capacity in m³/h at 1 bar pressure drop with the valve fully open. Equal-percentage flow characteristic gives you fine control near the closed position and more authority as the valve opens, which is the standard curve for modulating hydronic systems. The seat leakage is Class III (0.1%) on both the A-AB and B-AB ports, which means a small dribble at full shutoff — acceptable for mixing applications where absolute tight shutoff isn't required. If you need bubble-tight closure, this isn't the valve; look at a Class IV or V trim instead. Stem-up-closed action: when the actuator stem extends, the valve closes. That's the fail-safe default for normally-closed systems. The 11 mm stroke is short, so the actuator needs to be matched to that travel — an over-stroking actuator will damage the seat.
Materials and medium compatibility
Bronze body, brass plug (UNS C36000), brass trim — that's a standard combination for closed-loop hydronic systems with water or water-glycol mixtures up to 60% concentration. The operating fluid temperature range is -7 to 100 °C, which covers chilled water loops and low-temperature hot water heating. Don't use it for steam or high-temperature hot water above 100 °C.