Balancing Valve

Introduction to balancing valves

In HVAC systems and technical piping networks, balancing valves regulate and maintain the design flow rate at each branch. They help distribute flow evenly across zones, prevent overflow or insufficient flow, and establish a stable hydraulic balance from the commissioning stage.

During operation, balancing valves allow required flow settings to be adjusted and maintained over time. Many models include measuring ports for on-site testing and commissioning, making hydraulic adjustment easier for engineers. Their optimized design helps reduce energy consumption and improve overall system efficiency.

Watts products are well recognized for their extensive range and strong focus on HVAC applications. From manual balancing valves to pressure-independent flow control solutions, Watts emphasizes accuracy, stability, and long-term control performance, making them a preferred choice in the market.

Operating principle of balancing valves

In principle, balancing valves control flow by creating defined hydraulic resistance within the piping system. When adjusted to design requirements, they maintain the required flow rate at each branch and reduce the impact of pressure differences across the system. Depending on design and application, balancing valves operate in different ways.

• Manual Balancing Valve: Flow is adjusted manually by rotating the valve stem to a set position. After adjustment, the valve maintains the selected opening to keep the flow stable. Many models include pressure test ports for field measurement and commissioning.
• Balancing Valve with Measuring and Flow Limiting Function: The valve uses predefined flow characteristics for each opening position. Engineers can set the required flow using a scale or reference chart, reducing commissioning time and adjustment errors.
• Pressure Independent Control Valve (PICV): The valve automatically maintains constant flow within a specified differential pressure range. When system pressure changes due to other branches opening or closing, the internal mechanism adjusts to keep the preset flow rate.
• Differential Pressure Balancing Valve: This valve stabilizes the pressure difference between supply and return lines, helping downstream control valves operate more accurately and maintaining long-term hydraulic balance.

Watts Balancing Valve Product Line

Watts offers a comprehensive range of balancing valves, with each series optimized for specific operating conditions and flow control requirements. This allows engineers to select the most suitable solution for each project application. Below are some Watts balancing valve series currently distributed by Toan Cau:

Series W-STBV-25T         

The W-STBV-25T is a static balancing valve designed for chilled water, heating water, and process water systems. It is used to set and maintain the required design flow rate, helping the system operate stably and remain easy to control. The valve features integrated self-sealing test ports, a numeric opening position indicator, and a memory stop function that locks the preset position, making commissioning and maintenance more convenient. With these features, the W-STBV-25T meets the technical demands of modern HVAC systems.

Below are the key technical specifications of the W-STBV-25T series:

• Valve size: DN15 – DN50
• Body material: DZR Brass
• Nominal pressure: PN25
• Temperature range: -10°C to 120°C
• Connection standard: ISO 7-1
• Working medium: Non-corrosive liquids

Series W-STBV-25T

The W-STBV-25T is a static balancing valve designed for cooling water, heating water, and process water systems. The valve allows flow to be set and maintained according to design values, supporting fast and accurate system balancing. Key features of this series include self-sealing test ports, a clear graduated handwheel scale, and a locking function for the preset position. With a structure optimized for field measurement and commissioning, the W-STBV-25T performs reliably in HVAC applications requiring stable hydraulic operation.

Below are the key technical specifications of the W-STBV-25T series:

• Valve size: DN15 – DN50
• Body material: Bronze
• Nominal pressure: PN25
• Temperature range: -10°C to 120°C
• Connection standard: AS3688
• Working medium: Non-corrosive liquids 
• Certification: WaterMark

Series STBV-25 / 25N

The STBV-25 / 25N is a fixed orifice double regulating valve developed for cooling water, heating water, and process water systems that require accurate flow control from the commissioning stage. The valve is equipped with an integrated fixed orifice and measuring points, allowing faster flow measurement and balancing with reduced error. Its handwheel includes a numeric indicator and shut-off function, making maintenance more convenient. These features clearly distinguish the STBV-25 / 25N from conventional static balancing valves.

Below are the key technical specifications of the STBV-25 / 25N series:

• Valve size: DN15 – DN50
• Body material: Bronze
• Nominal pressure: PN25
• Temperature range: 0°C to 120°C
• Design standard: BS7350
• Connection standard: Threaded to ISO 7-1 / ASME B1.20.1
• Test standard: BS6755
• Working medium: Water
• Certification: WRAS

Series W-STBV-16Q

The W-STBV-16Q is a static balancing valve with a variable orifice design, developed for large HVAC systems and process water applications. The valve allows flexible flow adjustment through its variable throttling structure, making it suitable for large pipelines that require precise balancing. Key features include a pressure-balanced valve core, a handwheel with a clear numeric indicator, and self-sealing test ports. These features help the W-STBV-16Q deliver stable flow control, easy commissioning, and reliable long-term operation.

Below are the key technical specifications of the W-STBV-16Q series:

• Valve size: DN65 – DN500
• Body material: Ductile iron
• Nominal pressure: PN16
• Temperature range: -10°C to 120°C   
• Connection standard: BS EN 1092-2
• Working medium: Cold and hot water/glycol
• Certification: WRAS

Series W-STBV-25Q

The W-STBV-25Q series is a static balancing valve specifically designed for cooling water, heating water, and process water systems that operate under high flow demand. The valve allows accurate flow setting and stable flow maintenance, helping achieve proper system balancing from the initial commissioning stage. Key features include an optimized balancing valve core, a handwheel with numeric opening indication, and self-sealing test ports. With its durable ductile iron body, the W-STBV-25Q is well-suited for medium and large-sized HVAC systems.

Below are the key technical specifications of the W-STBV-25Q series:

• Valve size: DN65 – DN500
• Body material: Ductile iron GGG40
• Nominal pressure: PN25
• Temperature range: -10°C to 120°C
• Connection standards: GB/T 17241.6, ISO 7005
• Working medium: Cold and hot water/ethylene glycol

Series W-TDV-16Q/25Q

The W-TDV-16Q/25Q series is a multifunction 3-in-1 valve designed to combine the functions of shut-off valve, regulating valve, and check valve in a single unit. This solution helps reduce the number of valves required in the pipeline, optimize installation space, and simplify system operation. The valve allows direct flow adjustment through the handwheel while preventing reverse flow through its fast-closing internal mechanism. This integrated design is a key advantage of the W-TDV compared with traditional separate-valve arrangements.

Below are the key technical specifications of the W-TDV-16Q / 25Q series:

• Valve size: DN50 – DN500
• Body material: Ductile iron
• Nominal pressure: PN16 / PN25
• Temperature range: -20°C to 120°C
• Test standard: BS EN 12266-1
• Connection standards: GB/T 17241.6, EN 1092-2
• Connection type: Flanged
• Working medium: Water, glycol 

Series W-DPBV-20T

The W-DPBV-20T is a differential pressure balancing valve designed to maintain a stable pressure difference between supply and return lines at branch circuits, control valves, or terminal units in HVAC systems. The valve automatically compensates for differential pressure fluctuations caused by varying system loads, helping reduce hydraulic instability and improve operating consistency. The W-DPBV-20T offers a notable advantage: fully mechanical differential pressure control, which operates without electrical power. This makes it especially suitable for systems that demand high reliability and accurate pressure control.

Below are the key technical specifications of the W-DPBV-20T series:

• Valve size: DN15 – DN50
• Body material: Brass
• Nominal pressure: PN20
• Temperature range: -10°C to 120°C
• Connection standards: GB/T 7306.1, ISO 7/1
• Working medium: Cold and hot water/ethylene glycol

Series W-DPBV-16/25Q

The W-DPBV-16/25Q is a differential pressure balancing valve designed for medium and large HVAC systems where a stable pressure difference between supply and return lines is required. The valve automatically compensates for differential pressure changes caused by varying system loads, helping reduce hydraulic instability and protect downstream control valves. A key advantage of this series is its wide adjustment range, fully mechanical control mechanism, and design optimized for higher flow capacity. As a result, the W-DPBV-16 / 25Q provides high stability and reliable long-term operation.

Below are the key technical specifications of the W-DPBV-16 / 25Q series:

• Valve size: DN65 – DN150
• Body material: Ductile iron
• Nominal pressure: PN16, PN25
• Temperature range: -10°C to 130°C
• Connection standard: ISO 7005
• Working medium: Cold and hot water/ethylene glycol

Series W-DPBV-16Q

The W-DPBV-16Q is a differential pressure balancing valve designed to maintain a stable pressure difference between supply and return lines at branch circuits, control valves, or terminal units in HVAC systems. The valve operates through a fully mechanical mechanism that automatically compensates for differential pressure fluctuations caused by changing system loads. 

Key advantages of the W-DPBV-16Q include a wide differential pressure control range, a structure optimized for high flow capacity, and the ability to perform direct field measurement. These features help the system operate steadily while effectively reducing hydraulic instability.

Below are the key technical specifications of the W-DPBV-16Q series:

• Valve size: DN65 – DN150
• Body material: Ductile iron QT450-10
• Nominal pressure: PN16
• Temperature range: -10°C to 95°C
• Connection standard: ISO 7005
• Working medium: Cold and hot water/ethylene glycol

Series W-DP15-25T

The W-DP15-25T is a dynamic flow balancing valve designed for air conditioning and heating systems that require stable, design-specified flow rates. The valve automatically adjusts the valve core opening when system differential pressure changes, ensuring the flow rate does not exceed the preset value. A key advantage of this series is its high accuracy, with factory-preset flow settings that eliminate the need for field balancing. This makes it particularly well-suited for constant-flow systems, helping simplify operation and reduce installation costs.

Below are the key technical specifications of the W-DP15-25T series:

• Valve size: DN15 – DN40
• Body material: Brass
• Nominal pressure: PN25
• Temperature range: 0°C to 110°C
• Test standard: GB/T 13927-2008
• Connection standard: GB/T 7306.1-2000
• Connection type: Threaded
• Working medium: Water/Ethylene glycol

Series W-DP71-25Q

The W-DP71-25Q is a dynamic flow-balancing valve designed for large air-conditioning and heating systems where flow must be maintained within the design limit. Responding to differential pressure shifts, the valve automatically repositions its plug to maintain stable flow throughout operation. A key advantage of the W-DP71-25Q is its factory-calibrated cartridge, which delivers high accuracy alongside a wafer-style installation that saves space.

Below are the key technical specifications of the W-DP71-25Q series:

• Valve size: DN50 – DN500
• Body material: Ductile iron QT450-10
• Nominal pressure: PN25
• Temperature range: 0°C to 110°C
• Connection standards: GB/T 17241.6, GB/T 9113.1-2000
• Connection type: Wafer
• Working medium: Water / Ethylene glycol 

Series W-DP915-25T

The W-DP915-25T is a two-way electrically actuated dynamic balancing valve designed for FCU applications in air conditioning and heating systems. The valve combines on/off control through electrical signals with automatic flow balancing, helping eliminate hydraulic interference between terminal units. A key advantage of this series is the internal dynamic balancing cartridge, which maintains stable flow even when differential pressure changes. As a result, the W-DP915-25T improves temperature control accuracy and overall system efficiency.

Below are the key technical specifications of the W-DP915-25T series:

• Valve size: DN15 – DN25
• Body material: Anti-dezincification Brass CW602N
• Nominal pressure: PN25
• Temperature range: 0°C to 110°C
• Connection standard: ISO 7-1
• Connection type: Threaded
• IP grade of actuator: IP54
• Working medium: Water, ethylene glycol, propylene glycol 

Series W-PICVXXX-25T / 25Q

The W-PICVXXX-25T / 25Q is a pressure independent control valve (PICV) designed for terminal units in AHU, PAU, and MAU systems. The valve maintains stable flow through the valve even when the system differential pressure changes, eliminating interaction between branches. A key advantage of this series is its precise flow control combined with linear modulation, helping HVAC systems operate more steadily and efficiently. It is a preferred solution for applications requiring high accuracy and long-term energy performance.

Below are the key technical specifications of the W-PICVXXX-25T / 25Q series:

• Valve size: DN15 – DN50
• Body material:
  • DZR brass: DN15 – DN25
  • Bronze: DN32
  • Ductile iron: DN40 – DN50
• Nominal pressure: PN25
• Temperature range: -10°C to 120°C
• Connection standards: GB/T 7306.1, ISO 7-1
• Connection type: Threaded
• IP grade of actuator: IP54
• Working medium: Air conditioning hot and cold water, ethylene glycol solution

VAL-KIT

The WATTS VAL-Kit is a pre-assembled PICV kit for FCU applications, designed to achieve optimal hydraulic balancing in variable flow cooling and heating systems. The kit provides pressure-independent flow control, helping prevent overflow and maintain stable terminal unit performance. Its compact design integrates control, isolation, flushing, draining, and measuring functions into one complete accessory package.

Below are the key technical specifications of the WATTS VAL-Kit:

• Nominal pressure: PN20
• Temperature range: -10°C to 100°C
• Connection type: Threaded ends
• Working medium: Cold/hot water, 50% ethylene glycol

Series W-PICV-16/25Q (DN65-DN150)

The W-PICV-16/25Q is a pressure independent control valve (PICV) designed for terminal units in medium and large AHU, PAU, and MAU systems. The valve simultaneously regulates flow and maintains constant differential pressure across the valve, eliminating flow fluctuation when system operating conditions change. A key advantage of this series is its self-balancing pressure mechanism combined with electric control, delivering high accuracy and long-term stability. As a result, the W-PICV-16 / 25Q helps HVAC systems operate efficiently while reducing energy consumption.

Below are the key technical specifications of the W-PICV-16 / 25Q series:

• Valve size: DN65 – DN150
• Body material: Ductile iron QT450-10
• Nominal pressure: PN16/PN25
• Temperature range: -10°C to 130°C
• Connection standards: GB/T 17241.6, GB/T 9113.1-2000, ISO 7005
• Protection class: IP54
• Working medium: Water/ethylene glycol

Series W-PICV-16/25Q (DN200-DN250)

The W-PICV-16/25Q is a pressure independent control valve (PICV) engineered for large-flow AHU, PAU, and MAU terminal units. It maintains stable differential pressure across both ends while regulating flow, preventing flow disturbances from branch interactions elsewhere in the system. Its self-balancing structure, paired with electric control, provides high accuracy and reliable long-term operation. This makes it a suitable solution for HVAC systems that require high efficiency and energy savings.

Below are the key technical specifications of the W-PICV-16 / 25Q series (DN200 – DN250):

• Valve size: DN200 – DN250
• Body material: Ductile iron
• Nominal pressure: PN16 / PN25
• Temperature range: -10°C to 130°C
• Connection standards: GB/T 17241.6, ISO 7005
• Protection class: IP54
• Working medium: Water/ethylene glycol/propylene glycol

Series W-SCBV-20T/16Q/16C

The W-SCBV-20T, W-SCBV-16Q, and W-SCBV-16C belong to the smart control valve group developed for HVAC systems, water treatment, and central energy management applications. These products integrate a pressure independent control valve, intelligent actuator, and energy monitoring capability into one single device. A key advantage of the SCBV series is its real-time control accuracy, flexible communication with BMS platforms, and ability to optimize system operating efficiency.

Below are the key technical specifications of the W-SCBV-20T/16Q/16C:

• Valve size: DN15 – DN400
• Body material: 
  • Brass (DN15-DN50)
  • Ductile iron (DN50-DN200)
  • WCB (DN250-DN400)
• Nominal pressure:
  • PN20: Threaded connection DN15 – DN50
  • PN16: Flanged connection DN50 – DN400
• Temperature range: 4°C to 95°C
• Connection standards: 
  • GB/T 7307 (DN15-DN50)
  • GB/T 17241.6 (DN50-DN200)
  • GB/T 9113 (DN250-DN400)
• Protection class:
  • Actuator: IP67
  • Energy meter: IP65 (threaded), IP67 (flanged)
• Working medium: Hot and cold water, ≤50% ethyl/propylene glycol solution

Series W-WMS-16/25P

The W-WMS-16/25P is a flow measurement station designed to measure differential pressure and flow rate on both upstream and downstream sides of piping systems. Its compact wafer construction allows flexible installation, making it suitable for HVAC systems and technical water applications. A key advantage of this series is its simple design, durable SS304 stainless steel body, and high measurement stability. As a result, the W-WMS helps engineers monitor, evaluate, and balance systems more accurately in the field.

Below are the key technical specifications of the W-WMS-16 / 25P series:

• Valve size: DN50 – DN600
• Body material: Stainless steel
• Nominal pressure:
  • PN16: W-WMS-16P
  • PN25: W-WMS-25P
• Temperature range: -10°C to 120°C
• Connection type: Wafer
• Working medium: Water

Series W-STBV-TP

The W-STBV-TP is a pressure and flow test point used in heating and cooling systems for measurement, inspection, and operational record keeping. The device allows quick connection to field measuring instruments without interrupting system operation. Key advantages of this series include a self-sealing mechanism, compact structure, and strong corrosion resistance. With its simple design, the W-STBV-TP helps make testing procedures faster and safer.

Below are the key technical specifications of the W-STBV-TP:

• Body material: DZR brass
• Temperature range: -10°C to 120°C
• Connection standards:
  • BSPT 1/4 to BS21-1985
  • NPT 1/4 to ASME B1.20.1
• Working medium: Cold and hot water/glycol

Toan Cau – Exclusive Distributor of Watts Balancing Valves

Watts balancing valves are specially developed for HVAC systems, covering static balancing valves, dynamic balancing valves, differential pressure balancing valves, PICVs, and related measuring accessories. These products focus on flow accuracy, stable operation, and effective support for system commissioning, testing, and field adjustment, meeting the technical requirements of diverse project types.

In Vietnam, Toan Cau Building Materials Co., Ltd. is the exclusive distributor of Watts valve products, including the balancing valve range. The company also supplies pressure-reducing valves, air release valves, hot water control valves, and automatic control valves — all with genuine products and technically accurate consultation. For product selection support and a fast quotation, please contact the hotline 0911 771 551.