930005NT Dynamic Flow Balancing Valve

• Self-acting constant flow control across 50–500 kPa – Maintains 25 ± 5 L/min automatically across a ten-to-one differential pressure range without external power, actuators, or controls — using only the energy of the flowing water to operate the internal piston mechanism
• Eliminates manual hydraulic balancing – In systems using static balancing valves, commissioning engineers must manually set each valve to achieve design flow distribution. The 930005NT automatically maintains design flow at each terminal regardless of system pressure changes, eliminating the need for manual re-balancing after system modifications or zone changes
• Maintains design flow under partial load operation – When some zones are closed and system pressure redistribution occurs, the 930005NT continues to deliver design flow to the remaining open terminals, preventing over-flow conditions that waste energy and cause comfort complaints
• Works in both heating and cooling systems – Compatible with water systems from 0°C to 90°C, covering both chilled water cooling distribution and hot water heating circuits in the same product
• Hpb59-1 brass construction – High-quality leaded brass valve body provides durability and corrosion resistance in standard HVAC water circuits
• Dual seal system — EPDM and high-toughness plastic – Provides reliable sealing across the full temperature and pressure operating range of the valve
• No external power or controls required – Purely mechanical operation driven by differential pressure, with no electrical connections, control signals, or batteries needed
• OEM and ODM customization available – Flow rate, pressure range, and connection size can be customized for specific system requirements

The 930005NT uses a spring-loaded piston inside the valve core to regulate flow across three operating conditions based on differential pressure (ΔP) across the valve:

Below 50 kPa (below minimum design pressure difference): The piston does not engage flow control. Flow increases proportionally with differential pressure — the valve behaves like an open orifice. This condition occurs only during startup or in very low-load conditions.

Between 50 kPa and 500 kPa (design operating range): The piston automatically adjusts the variable-diameter orifice in response to differential pressure changes. As ΔP increases, the variable-diameter path progressively closes while the fixed-diameter path compensates, keeping the total combined flow constant at 25 ± 5 L/min. This is the normal operating condition where the valve actively maintains design flow regardless of pressure fluctuations.

Above 500 kPa (above maximum design pressure difference): Water pressure fully closes the variable-diameter orifice. All flow passes through the fixed-diameter path only, and flow increases again with differential pressure. This condition indicates that system pressure is outside the valve’s balancing range.

The valve’s flow-vs-pressure curve shows a flat plateau between 50 kPa and 500 kPa at approximately 1.5 m³/h, confirming consistent flow delivery across the full design pressure range.

• District heating system terminal connections – Each radiator, fan coil, or AHU connection in a district heating network receives a consistent design flow regardless of pressure fluctuations caused by other buildings or zones opening and closing on the network
• Variable flow HVAC systems with multiple zones – In systems where zone control valves open and close based on thermostat demand, residual pressure redistributes across remaining open branches. The 930005NT prevents flow runaway in open branches when other zones close
• Fan coil units in commercial buildings – Each FCU receives its design flow at all times, preventing over-cooling or over-heating due to hydraulic imbalance in large multi-zone commercial HVAC installations
• Air handling units – Maintains consistent coil water flow for accurate supply air temperature control, preventing performance degradation caused by hydraulic pressure fluctuations in the building’s chilled or hot water distribution system
• Radiator systems in multi-apartment buildings – Ensures each apartment’s radiator circuit receives its design flow without requiring manual rebalancing when other apartments adjust their heating or when district supply pressure fluctuates
• Partial load operation scenarios – When only a portion of terminals are active (partial load), the 930005NT maintains correct flow in active terminals regardless of the elevated differential pressure caused by inactive branches

• The 930005NT can be installed in any orientation — the working principle diagram confirms both vertical and horizontal installation are supported
• Ensure water flow direction matches the arrow marked on the valve body. Reverse installation prevents the piston mechanism from functioning correctly
• Flush the pipeline thoroughly before installation to remove grit, scale, and debris that could lodge in the variable-diameter orifice and prevent correct piston operation
• Install isolation valves upstream and downstream to enable valve removal and servicing without draining the system
• The valve operates correctly only within the 50–500 kPa differential pressure range. Verify that the system design provides differential pressure within this range at the valve’s installation point under all operating conditions
• Use appropriate thread sealant or PTFE tape on the G3/4″ FXF threaded connections
• After installation, verify flow rate at the terminal using a flow meter or commissioning device to confirm the valve is operating within its balanced zone

Legom supports OEM and ODM services for the 930005NT Dynamic Flow Balancing Valve. Our engineering team can customize flow rate, differential pressure range, connection size, and body material to match specific system requirements. All customization projects are handled with strict confidentiality. Contact us via WhatsApp or info@legomsmart.com.