Balancing valves work to achieve hydraulic balance within hydronic systems by regulating fluid flow and pressure. By maintaining flow conditions in HVAC systems and allowing control valves to function correctly, balancing valves eliminate unbalanced system issues such as wide temperature variations and increased energy needs.
Types of Balancing Valves
Various types of balancing valves are available to suit different hydronic systems, including:
Automatic Balancing Valves
Also known as pressure-independent or dynamic balancing valves, these valves automatically maintain a fixed flow rate value, despite changes in differential pressure, to optimize system operation. In contrast to manual balancing valves, these valves have internal parts that move to compensate for changes in differential pressure, enabling them to operate more efficiently under variable load conditions.
Manual Balancing Valves
Also called pressure-dependent balancing valves, manual balancing valves offer a fixed resistance to water flow. Their settings are calculated before installation and adjusted when installed in the field. The internal valve parts of manual balancing valves remain static during system operations.
Fixed-Orifice Balancing Valves
These valves are static balancing valves that feature a fixed orifice, such as a Venturi insert, combined with pressure/temperature ports that enable measurement of the differential pressure across the orifice. Because the orifice remains set during valve adjustments, the system’s flow rate can be derived by the pressure drop measured across the ports. Fixed-orifice balancing valves are very efficient.
Direct Reading Balancing Valves
A variation of a fixed-orifice valve, direct reading valves do not require ΔP readings. Instead, they use a built-in flow meter. A balancing technician directly reads the flow rate, simplifying balancing, reducing balancing labor time significantly, and eliminating errors. Direct reading valves contain a bypass channel connected to both sides of a fixed venturi.
Pressure-Independent Flow Control Valves
All-in-one devices that combine the capabilities of balancing valves, control valves, and differential pressure regulators, pressure-independent flow control valves feature built-in differential pressure regulators that automatically accommodate changes in system pressure to stabilize flow within the heating or cooling components to meet different temperature demands. In addition, these valves can be used with actuators that provide remote flow control capabilities.
Thermal Balancing Valves
Designed primarily for balancing domestic hot water recirculation circuits, thermal balancing valves modulate the flow rate within a circuit to maintain a fixed temperature and ensure adequate water temperature at the fixtures. In addition, some thermal balancing valve models are available with a bypass feature that allows for use in a thermal disinfection application to control Legionella. Both fixed temperature (non-adjustable) and field-adjustable thermal balancing valves are available.
Bell & Gossett Balancing Valves
Bell & Gossett manual and flow balancing valves provide adjustability and efficiency. Circuit setter valves provide pre-set proportional balance and assure optimum system flow balance at minimum operating horsepower. Venturi valves provide balance, ease of commissioning, and shut-off in various HVAC systems.
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NIBCO Balancing Valves
Automatic and manual balancing valves from NICBO are ideally suited for HVAC and other mechanical applications requiring a balanced system providing optimum flow. NIBCO FLO-BOSS® valves and connectors keep indoor spaces comfortable and energy efficient. NIBCO balancing and control valves work with heating, cooling, or water distribution systems to deliver optimum performance and trouble-free maintenance.
