Introduction: The Role of Valves in HVAC Systems
Heating, Ventilation, and Air Conditioning (HVAC) systems are essential to the comfort, safety, and energy efficiency of commercial buildings, data centres, hospitals, industrial facilities, and marine HVAC installations. These systems rely on the precise control of water, air, steam, and refrigerants, and this control is made possible through the correct selection and installation of valves.
In HVAC applications, valves perform multiple functions:
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Isolating equipment for maintenance
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Regulating flow for temperature control
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Balancing systems to ensure even distribution
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Protecting equipment from over-pressure or backflow
Selecting the wrong valve type or material can lead to poor system performance, energy wastage, noise, premature failure, and costly downtime. As a Singapore-based marine and industrial valve stockist and distributor, Aik Soon Hardware supports HVAC contractors, M&E consultants, and facility managers with reliable valves suitable for both building and marine HVAC systems.
This guide explores the different types of valves used in HVAC systems, their applications, materials, operating mechanisms, and key selection criteria.
1. Key HVAC Systems Where Valves Are Used
Valves are found throughout HVAC systems, including:
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Chilled water systems
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Condenser water systems
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Hot water heating systems
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Steam and condensate lines
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Air handling units (AHUs)
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Fan coil units (FCUs)
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Cooling towers
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Heat exchangers
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District cooling systems
Each system imposes different temperature, pressure, and control requirements on valves.
2. Main Types of Valves Used in HVAC Applications
2.1 Ball Valves (Isolation Valves)
Description
Ball valves use a rotating ball with a bore to provide quick shut-off. They are quarter-turn valves and are among the most commonly used HVAC isolation valves.
Where Used in HVAC
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AHU and FCU isolation
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Pump suction and discharge
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Chilled and hot water branches
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Equipment maintenance isolation
Materials Used
Advantages
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Fast operation
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Compact size
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Tight shut-off
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Low maintenance
Limitations
2.2 Gate Valves (Main Line Isolation)
Description
Gate valves use a sliding gate to fully open or fully close flow.
Where Used
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Chilled water mains
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Condenser water mains
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Pump isolation
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Plant room pipelines
Materials Used
Advantages
Limitations
2.3 Butterfly Valves (Large Diameter HVAC Lines)
Description
Butterfly valves use a rotating disc and are ideal for large-diameter HVAC piping.
Where Used
Materials Used
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Ductile iron body
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Stainless steel disc
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EPDM or NBR rubber seat
Advantages
Limitations
2.4 Globe Valves (Flow Regulation)
Description
Globe valves regulate flow by moving a disc against a seat, offering excellent throttling capability.
Where Used
Materials Used
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Bronze
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Cast iron
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Carbon steel
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Stainless steel
Advantages
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Precise flow control
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Reliable throttling
Limitations
2.5 Balancing Valves
Description
Balancing valves are designed to control and measure flow to ensure even distribution throughout the HVAC system.
Types
Where Used
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AHUs and FCUs
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Branch lines
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Chilled water circuits
Materials Used
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Brass
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Bronze
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Ductile iron
Advantages
2.6 Control Valves (Modulating Valves)
Description
Control valves automatically regulate flow based on temperature, pressure, or flow signals from the Building Management System (BMS).
Where Used
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AHU cooling coils
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FCU units
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Heat exchangers
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Chiller bypass lines
Types
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2-way control valves
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3-way control valves
Materials Used
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Brass
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Cast iron
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Stainless steel
Advantages
2.7 Check Valves (Non-Return Valves)
Description
Check valves prevent reverse flow and protect pumps and equipment.
Where Used
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Pump discharge lines
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Condenser water systems
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Booster pumps
Types
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Swing check valves
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Lift check valves
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Dual-plate check valves
Materials Used
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Cast iron
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Bronze
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Stainless steel
2.8 Pressure Reducing Valves (PRVs)
Description
PRVs reduce incoming water pressure to safe levels.
Where Used
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High-rise HVAC systems
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Zone pressure control
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Mechanical rooms
Materials Used
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Brass
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Bronze
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Stainless steel
2.9 Safety & Relief Valves
Description
Protect HVAC equipment from over-pressure conditions.
Where Used
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Boilers
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Hot water systems
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Heat exchangers
3. Valve Materials Used in HVAC Applications
| Material |
Typical HVAC Use |
| Brass |
FCUs, AHUs, plumbing |
| Bronze |
Hot water, fire systems |
| Cast Iron |
HVAC mains |
| Ductile Iron |
Chilled & condenser water |
| Stainless Steel |
Corrosive environments |
| Carbon Steel |
High-pressure steam |
Material selection must consider corrosion resistance, temperature, pressure, and water quality.
4. How to Select the Right Valve for HVAC Systems
4.1 Define the Valve Function
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Isolation → Ball, Gate, Butterfly
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Regulation → Globe, Control
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Balancing → Manual or PICV
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Protection → Check, Safety
4.2 Determine Operating Conditions
4.3 Consider System Size & Space
4.4 Energy Efficiency
4.5 Automation Requirements
4.6 Compliance & Standards
Ensure valves comply with:
5. Common HVAC Valve Selection Mistakes
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Using gate valves for balancing
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Oversizing control valves
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Incorrect seat material selection
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Ignoring future maintenance access
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Inadequate pressure rating
Conclusion
Valves are essential components that directly influence HVAC system performance, energy efficiency, and reliability. From ball and butterfly valves for isolation to control and balancing valves for temperature regulation, selecting the correct valve type and material is critical for achieving optimal HVAC operation.
As a trusted Singapore-based marine and industrial valve distributor, Aik Soon Hardware supports HVAC professionals with high-quality valves designed for durability, efficiency, and compliance. Whether for commercial buildings, industrial plants, or marine HVAC systems, our expertise ensures the right valve solution for every application.