The Comprehensive Guide to Check Valves for Shallow Well Pumps

A check valve is a crucial component in a shallow well pump system, ensuring the proper functioning and longevity of the pump. Its primary role is to prevent water from flowing back into the well when the pump turns off, maintaining the prime and protecting the system from various issues like backspin, water hammer, and upthrust.

Understanding the Importance of Check Valves in Shallow Well Pumps

Shallow well pumps are designed to draw water from a water table that is relatively close to the surface, typically less than 25 feet deep. These pumps rely on the atmospheric pressure to push water up the suction pipe and into the pump. However, without a check valve, the water in the suction pipe can flow back into the well when the pump is turned off, causing the pump to lose its prime and potentially leading to issues like:

1. Backspin: When the pump shuts off, the water in the suction pipe can flow back into the well, causing the pump to spin in reverse, which can damage the motor and other components.
2. Water Hammer: The sudden reversal of water flow can create a pressure surge, known as water hammer, which can damage the piping and other system components.
3. Upthrust: The backflow of water can create an upward force on the pump’s impeller, leading to increased wear and tear on the bearings and other moving parts.

By installing a check valve, you can prevent these issues and ensure the long-term reliability and efficiency of your shallow well pump system.

Selecting the Right Check Valve for Your Shallow Well Pump

When choosing a check valve for your shallow well pump, there are several technical specifications and hands-on details to consider:

Flow Velocity

The ideal flow velocity for most check valves is below 3 m/s (9.8 ft/s) to ensure optimal service life. Exceeding this flow velocity can lead to increased wear and tear on the valve components, reducing its lifespan. To calculate the flow velocity, you’ll need to know the pump’s flow rate and the diameter of the pipe or valve.

System Pressure

The check valve must be rated for the maximum system pressure, which includes not only the pump’s pressure setting but also the static head and any other pressure drops in the system. Underestimating the system pressure can result in a check valve that fails prematurely.

Spring-Assisted Poppet

The recommended check valve for a well pump’s plumbing system is a spring-assisted poppet valve. This type of valve quickly closes when the pump shuts off, minimizing the risk of water hammer and other issues caused by backflow.

Installation Considerations

Before installing the check valve, ensure that it has no defects and that the spring-assisted poppet moves freely. The arrow on the valve’s body should face the intended flow direction when the pump operates.

Materials

Select a check valve made of durable materials suitable for well pump applications, such as brass, stainless steel, or engineered plastics. The materials should be compatible with the system’s pressure and temperature requirements.

Installing a Check Valve for a Shallow Well Pump

If you’re taking a DIY approach to installing a check valve for your shallow well pump, follow these steps:

1. Inspect the Current Setup: Examine the existing plumbing system to identify the best location for the check valve, typically between the pump and the water intake.
2. Choose the Right Check Valve: Select a check valve that meets the system’s flow velocity, system pressure, and material requirements. Consider the valve’s size, connection type (threaded, flanged, etc.), and any special features like a built-in strainer or isolation valves.
3. Prepare the Piping: Before installing the check valve, ensure the piping is free of debris and obstructions. If necessary, clean the piping to ensure proper check valve operation.
4. Install the Check Valve: Position the check valve in the desired location, aligning the arrow on the valve’s body with the intended flow direction. Secure the valve using appropriate fittings and connections, such as threaded or soldered joints.
5. Test the System: After installing the check valve, run the pump to verify that it maintains prime and that the check valve functions correctly, preventing water from flowing back into the well.

Maintaining and Troubleshooting the Check Valve

Regular maintenance and inspection of the check valve can help ensure its long-term performance and prevent potential issues. Some key maintenance tasks include:

• Checking for any signs of wear or damage, such as cracks, corrosion, or stuck poppets
• Verifying that the spring-assisted poppet moves freely and closes quickly when the pump shuts off
• Cleaning the valve’s interior and any attached strainers or filters to remove debris
• Replacing the check valve if it is no longer functioning properly or if the system’s requirements have changed

If you encounter any issues with the check valve, such as a loss of prime or water hammer, troubleshoot the problem by:

• Inspecting the check valve for any visible defects or obstructions
• Checking the system pressure and flow velocity to ensure they are within the valve’s specifications
• Verifying that the check valve is installed in the correct orientation and location
• Considering the need to replace the check valve if it is worn or damaged beyond repair

By understanding the importance of check valves in shallow well pump systems and following best practices for selection, installation, and maintenance, you can ensure the reliable and efficient operation of your water supply system.

References

1. Question about shallow well pumps and check valves : r/Plumbing
2. CONTROL VALVE HANDBOOK | Emerson
3. Check valve between pump and tank – Love Plumbing & Remodel
4. Well Pump Check Valve | Tameson.com
5. Purpose of Check Valve combined with shallow well pump? – Plbg.com