WATTS LF919-QT-S Reduced Pressure Zone Backflow Preventer
( Brand: Watts ), ( Manufacturer Part Number: LF919-QT-S ), ( Part Type: Pressure ), ( Pipe Size: 2 In ), ( Backflow Preventer Type: Reduced Pressure Zone ), ( Country Of Origin: United States )
Review WATTS Lf919 Quart Inch Reduced Pressure Zone Backflow Preventer Assembly
The **Watts LF919-QT-S LF919 Reduced Pressure Zone (RPZ) Backflow Preventer** is a high-performance, full-port, double-check valve assembly designed to provide superior protection against backflow contamination in critical water distribution systems. Engineered to meet or exceed the rigorous standards set by the American Society of Sanitary Engineering (ASSE) 1050 and the International Association of Plumbing and Mechanical Officials (IAPMO), this RPZ backflow preventer is an indispensable solution for commercial, municipal, and industrial applications where water quality integrity is non-negotiable. The LF919-QT-S features a robust, cast iron body with a durable, powder-coated finish, ensuring long-lasting durability and resistance to corrosion in harsh environments. Its compact yet full-port design minimizes pressure loss while maintaining optimal flow rates, making it ideal for high-demand systems such as fire protection, irrigation, and potable water supply lines.
At the heart of the LF919-QT-S is its advanced Reduced Pressure Principle (RPP) mechanism, which combines a primary check valve, a secondary check valve, and a pressure differential relief valve to create a sealed, reduced-pressure zone that effectively isolates the supply system from potential contaminants. The primary check valve prevents backflow during normal operation, while the secondary check valve acts as a fail-safe, ensuring that even if the primary valve fails, the system remains protected. The pressure differential relief valve further enhances safety by venting excess pressure, preventing overstress on the system and reducing the risk of catastrophic failure. The assembly is equipped with a built-in test port and a pressure gauge, allowing for easy and accurate testing to verify the integrity of the backflow preventer and ensure compliance with local and national regulations.
The LF919-QT-S is designed with user convenience in mind, featuring a quick-connect coupling system that simplifies installation and maintenance. The valve s compact footprint and full-port design allow for seamless integration into existing piping systems without requiring extensive modifications, saving time and reducing labor costs. Additionally, the assembly is equipped with a robust gasket system and threaded connections, ensuring a secure and leak-proof seal that maintains water quality and system efficiency. For added reliability, the LF919-QT-S is available with optional stainless steel components, including the check valve seats and springs, which further enhance resistance to corrosion and wear, extending the device s operational lifespan in demanding applications.
Watts Industries has incorporated several innovative features into the LF919-QT-S to improve functionality and safety. The valve includes a built-in bypass valve, which allows for maintenance or testing without shutting down the entire system, minimizing downtime and operational disruptions. The assembly also features a clear, labeled test cock and pressure gauge, making it easy for operators to perform routine inspections and tests in accordance with industry best practices. Furthermore, the LF919-QT-S is designed to accommodate a wide range of pipe sizes, from 1 to 2 inches, providing flexibility for various applications while maintaining consistent performance. Whether installed in a residential sprinkler system, a commercial building s potable water supply, or a municipal water treatment facility, this RPZ backflow preventer delivers unmatched protection and reliability.
In summary, the **Watts LF919-QT-S LF919 Reduced Pressure Zone Backflow Preventer** is a cutting-edge, full-port valve assembly that combines superior engineering, durability, and ease of use to safeguard water systems against backflow contamination. Its advanced design, compliance with industry standards, and innovative features make it a trusted choice for professionals who demand the highest level of performance and protection in their water distribution systems. With minimal maintenance requirements and a focus on long-term reliability, the LF919-QT-S ensures that water quality remains pristine while maintaining optimal system efficiency.
The **Watts LF919-QT-S Reduced Pressure Zone (RPZ) Backflow Preventer** is a high-quality device designed to protect potable water systems from contamination by preventing backflow. Below is a detailed breakdown of its pros and cons, followed by a conclusion and recommendation.
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### **Pros of the Watts LF919-QT-S RPZ Backflow Preventer**
1. **Superior Backflow Protection**
The RPZ assembly is one of the most reliable types of backflow preventers, offering double-check valve protection with an integral atmospheric vacuum breaker. This ensures that even if one valve fails, the other remains operational, preventing contamination of the water supply.
2. **Compliance with Industry Standards**
Watts is a well-known manufacturer in the water control industry, and this model meets or exceeds **NSF/ANSI Standard 61** (for materials) and **NSF/ANSI Standard 312** (for performance), ensuring it is safe for potable water applications. It is also **ASSE 1015** certified, which is a key requirement for many municipal and commercial installations.
3. **Durable Construction**
The assembly is built with **brass or stainless steel components**, which are resistant to corrosion and long-lasting. The reduced pressure zone design helps maintain consistent water pressure while preventing backflow.
4. **Easy Installation and Maintenance**
The LF919-QT-S is designed for straightforward installation, with clear labeling and standard thread sizes for easy connection to piping systems. Maintenance involves periodic testing and occasional lubrication of the internal components, which is relatively simple compared to other backflow devices.
5. **Wide Range of Applications**
This model is suitable for **residential, commercial, and light industrial** applications, including single-family homes, apartment buildings, and small businesses. It is often required by **municipal water departments** where backflow prevention is mandatory.
6. **Reliable Pressure Differential Operation**
The RPZ assembly uses a **pressure differential mechanism** to close the valves when backflow is detected, making it highly responsive to changes in water flow direction.
7. **Tested and Certified for Safety**
The device undergoes rigorous testing to ensure it functions correctly under various conditions, including pressure surges and backflow scenarios. This reduces the risk of system failure.
8. **Available in Multiple Sizes**
Watts offers this model in various sizes (e.g., 3/4", 1", 1-1/4", etc.), allowing for flexibility in different plumbing setups.
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### **Cons of the Watts LF919-QT-S RPZ Backflow Preventer**
1. **Higher Upfront Cost**
Compared to simpler backflow preventers (such as reduced pressure principle assemblies or double-check valves), the LF919-QT-S is more expensive due to its advanced design and certification. The cost can range from **$300 to $800 **, depending on the size and material.
2. **Requires Professional Installation**
While the installation is not overly complex, it should ideally be done by a **licensed plumber or backflow tester** to ensure proper sealing, alignment, and compliance with local codes. DIY installation may void warranties or fail inspections.
3. **Regular Testing and Maintenance Required**
RPZ assemblies must be **tested annually** by a certified backflow tester to ensure they are functioning correctly. Failure to do so can result in fines or service disruptions. Maintenance may also require occasional replacement of seals or lubrication of internal parts.
4. **Space Constraints**
The LF919-QT-S is a larger assembly compared to some other backflow preventers, which may require additional space in tight plumbing setups. This could be a consideration in older homes or commercial buildings with limited access.
5. **Potential for False Positives in Testing**
In rare cases, the assembly may trigger false backflow alarms during testing if not properly adjusted or if there are minor leaks. This can lead to unnecessary service calls.
6. **Limited Lifespan Compared to Simpler Devices**
While durable, RPZ assemblies have a **lifespan of 10 15 years** under normal conditions, after which components may wear out and require replacement. This is longer than some basic backflow preventers but shorter than permanent installations like pressure vacuum breakers in non-critical applications.
7. **Dependence on Water Pressure**
The RPZ assembly relies on consistent water pressure to function correctly. In areas with **fluctuating pressure**, it may require additional monitoring or adjustments.
8. **Not Suitable for All Applications**
While versatile, the LF919-QT-S is **overkill for very low-risk residential applications** (e.g., a single hose bib in a suburban home). In such cases, a simpler device like a **pressure vacuum breaker (PVB)** may suffice, reducing cost and complexity.
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### **Conclusion**
The **Watts LF919-QT-S RPZ Backflow Preventer** is one of the most robust and reliable options for protecting potable water systems from backflow contamination. Its **double-check valve design, compliance with industry standards, and durability** make it an excellent choice for **residential, commercial, and light industrial settings where backflow prevention is legally required or highly recommended**.
However, its **higher cost, need for professional installation and testing, and maintenance requirements** may not justify its use in low-risk scenarios. If backflow protection is mandatory by local water authorities or if the application involves **hazardous substances (e.g., fertilizers, chemicals)**, this assembly is an ideal investment. For less critical applications, a simpler and less expensive backflow device may be sufficient.
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### **Recommendation**
**Buy the Watts LF919-QT-S RPZ Backflow Preventer if:**- You are required by **municipal or commercial water regulations** to install an RPZ assembly.
- Your application involves **hazardous or non-potable substances** that could contaminate the water supply.
- You need **maximum backflow protection** for a residential or commercial property.
- You are willing to **budget for professional installation and annual testing**.
**Consider an alternative (e.g., Watts LF919-QT or a simpler PVB) if:**- Your application is **low-risk** (e.g., a single hose bib in a residential home).
- You want to **reduce upfront costs** and maintenance complexity.
- Local codes allow for a **less stringent backflow device** (e.g., a reduced pressure principle assembly or double-check valve).
For most **high-risk or legally mandated installations**, the LF919-QT-S is the **best choice** due to its reliability and compliance. However, always verify local regulations and consult a **licensed plumber or backflow tester** to ensure it meets your specific needs.
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part #: lf919qt prices
- $275.00-$695.00
specifications valvesplumbing:
- brand: Watts
- mpn: Lf919-qt-s
- part type: Pressure
- pipe size: 2 In
- backflow preventer type: Reduced Pressure Zone
- country of origin: United States
general valvesplumbing:
- Hydraulics, Pneumatics, Pumps Plumbing > Valves Manifolds > Backflow Preventers
- condition: Used
offer valvesplumbing:
- started: March 28, 2026
- quantity: 1
- availability: In Stock
- sold: 0
- options: Ship-to-home
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- transit: 4-7 Days
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- carrier: UPS
- cost: $0.00
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- # reviews: 38984
- city: Columbus, Ohio
- rating: 99.4%
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returns valvesplumbing:
- time: 30 Days
- paid by: Seller
- method: Money back
- policy: Returns Accepted
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