Introduction to Backflow Preventers Valve

Backflow Preventers Valve are installed in water supply and technical piping systems to stop reverse flow from returning to the source. They protect water quality from contamination caused by pressure differences or sudden pressure drops. Depending on risk level, they are available as single check units, double check assemblies, or models with integrated pressure control.

Technically, Backflow Preventers Valve require fast response, reliable sealing, and low pressure loss to maintain normal system flow. Their design supports automatic operation, easy inspection, and compliance with standards used in water supply, HVAC, and fire protection systems, ensuring long-term reliability.

Products from Watts Water Technologies are recognized for application-focused engineering. Watts emphasizes mechanical precision, durable materials, and in-line serviceability, helping systems operate reliably while reducing downtime. Its broad product range also supports easier selection for engineers and contractors across many project types.

Operating Principle of Backflow Preventers Valve

Backflow Preventers Valve operate according to pressure changes within the piping system. Under normal conditions, they allow flow in the intended direction with minimal pressure loss. When abnormal pressure occurs, the internal check components react immediately to stop reverse flow, protecting the water supply and upstream equipment.

• Normal flow condition:  Supply pressure is higher than the downstream pressure. The internal check valves open, allowing fluid to pass in the designed direction while maintaining stable flow.

• Backpressure condition: When downstream pressure exceeds supply pressure, the check valves close automatically, creating a barrier that prevents reverse flow to the source.

• Backsiphonage condition: When supply pressure drops suddenly, the pressure differential may draw fluid backward. The check valves close immediately. Some advanced models also include a relief chamber or intermediate zone for added protection.

• Testing and maintenance function: On models with test ports, technicians can inspect each check valve without removing the device from the pipeline, making maintenance and system monitoring more efficient.

Watts Backflow Preventers Valve Product Line

Watts offers a comprehensive range of Backflow Preventers Valve spanning various configurations and standards to address the technical requirements and protection levels of different systems. Each series targets specific applications, enabling more accurate product selection based on actual operating conditions.

Series 007-QT

The 007-QT series is a double check backflow preventer from Watts, designed to protect water supplies at cross-connection points in distribution systems. The valve features a top-mounted construction that allows in-line testing and maintenance, reducing service time and minimizing operational downtime. Its compact modular design and low pressure loss help maintain stable flow during operation. Compared with many products in the same class, the 007-QT stands out for its high mechanical quality, easy servicing, and long-term reliability in real-world use.

Below are the key technical specifications of the 007-QT series:

• Valve size: DN15 – DN50
• Body material: Bronze
• Nominal pressure: 1.21 MPa
• Temperature range: 0.5°C to 82°C
• Working medium: Water
• Certification: WaterMark

Series 009-QT

The 009-QT series is a Double Check Backflow Preventer from Watts, designed for water supply systems that need reliable backflow protection. The valve features a top-entry design with a single access cover, allowing inspection and replacement of internal components directly on the pipeline. Its modular construction and wide flow path help reduce pressure loss and maintain stable flow performance. Compared with many valves in the same class, the 009-QT stands out for convenient maintenance and long-term durability.

Below are the key technical specifications of the 009-QT series:

• Valve size: DN15 – DN50
• Body material: Bronze
• Nominal pressure: 1.21 MPa
• Temperature range: 0.5°C to 75°C
• Connection standard: G – GB/T 7307
• Working medium: Water
• Certification: WaterMark

Series 7R

The 7R series is a Dual Check Valve from Watts, designed for low-risk residential water supply systems. It is used to prevent backflow and backsiphonage under continuous operating pressure conditions. The valve houses two replaceable check modules in a compact, durable body — fitting easily into tight spaces and meter assemblies alike. Compared with many valves in the same category, the 7R stands out for its strong mechanical durability, low pressure loss, and flexible installation in both horizontal and vertical positions.

Below are the key technical specifications of the 7R series:

• Valve size: DN15 – DN50
• Body material: DR brass
• Nominal pressure: 1207 kPa
• Temperature range: 0.5°C to 82°C
• Connection standard: AS/NZS 2845.1
• Connection type: BSP female thread
• Working medium: Non-corrosive liquids
• Certification: WaterMark

Series 9D

The 9D series is a Dual Check Valve with Intermediate Atmospheric Vent from Watts, designed for small-sized water supply lines. It is especially suitable for laboratory equipment, sterilizers, treatment tanks, dairy equipment, and boiler feed water lines. A key feature of the Series 9D is its atmospheric vent mechanism, which discharges to the atmosphere if the downstream check valve leaks, helping protect potable water systems. Its compact design provides stable operation under continuous pressure and is suitable for both hot and cold water service.

Below are the key technical specifications of the 9D series:

• Valve size: DN15 – DN20
• Body material: Brass
• Nominal pressure: 1210 kPa
• Temperature range: 0.5°C to 121°C
• Connection standard: AS/NZS 2845.1
• Connection type: BSP female thread
• Working medium: Non-corrosive liquids
• Certification: WaterMark

Series SCVT

The SCVT series is a Single Check Testable Valve Assembly from Watts, developed for commercial water supply and fire protection systems. It is installed on large-diameter pipelines to prevent backsiphonage and backpressure from sources that may create contamination risks. The epoxy-coated ductile iron body provides high durability under continuous operating conditions. Its in-line testable design allows convenient inspection and scheduled maintenance, offering advantages over standard check valves.

Below are the key technical specifications of the SCVT series:

• Valve size: DN80 – DN200
• Body material: Ductile iron coated with epoxy
• Nominal pressure: 1200 kPa
• Maximum temperature: 60°C
• Design standard: AS/NZS 2845.1
• End connections:
  • Grooved (cut for steel pipe): AWWA C606
  • Flanged: AS 2129-2000 – Table E
• Certification: WaterMark 
• Working Medium: Non-corrosive liquids

Series SCDAT

The SCDAT is a backflow prevention assembly designed for potable water lines serving fire protection systems, supporting testing and flow monitoring during operation. The device effectively prevents back-siphonage and backpressure from potentially contaminated water returning to the clean water supply. It is built with a durable ductile iron body and includes an auxiliary piping assembly for low-flow detection, helping meet system safety management requirements. The Series SCDAT comes with flanged or grooved end connections, accommodating large pipelines from DN80 to DN200.

Below are the key technical specifications of the SCDAT series:

• Valve size: DN80 – DN200
• Body material: Ductile iron
• Nominal pressure: 1200 kPa
• Maximum temperature: 60°C
• Connection standard: AS/NZS 2845.1
• End connection types:
  • Grooved (cut for steel pipe): AWWA C606
  • Flanged: AS 2129-2000
• Certification: WaterMark

Series DCDA Flomatic

The DCDA Flomatic® is a Double Check Detector Assembly from Watts, designed for fire protection systems operating under continuous pressure. It is intended for medium hazard conditions, helping prevent backflow caused by backpressure or backsiphonage. The integrated detector assembly allows monitoring of low water usage, supporting leak detection and efficient system supervision. Compared with standard double check assemblies, the DCDA Flomatic® stands out for stable performance, in-line testability, and long service life.

Below are the key technical specifications of the DCDA Flomatic® series:

• Valve size: DN65 – DN200
• Body material: Ductile iron coated with epoxy
• Nominal pressure: PN12
• Temperature range: 0°C to 60°C
• Design standard: AS 2845.1
• Test standard: AS 2845.1 Section 11
• Connection type: AS 2129-2000 Flanged Table E 
• Working medium: Non-corrosive liquids
• Certification: WaterMark

Watts Backflow Preventers Valve – Exclusively Distributed by Toan Cau

Watts Backflow Preventers Valve are developed in accordance with strict engineering standards to protect water quality in water supply and fire protection systems. The product range is clearly classified by hazard level and operating conditions, helping engineers and contractors choose the most suitable solution for different project requirements.

In Vietnam, Toan Cau Building Materials Co., Ltd. is the exclusive distributor of Watts Backflow Preventers Valve. In addition, Toan Cau supplies a full range of other Watts products, including automatic control valves, pressure reducing valves, safety valves, and air release valves, supporting complete and coordinated piping system solutions.

With more than 18 years of experience in building material solutions and modern industrial equipment, Toan Cau is trusted by many partners for accurate technical consultation, genuine products, and project-based support. For technical information or a detailed quotation on Watts valve products, please contact the hotline 0911 771 551 for fast and professional assistance.