Shallow well pumps are essential components in water supply systems, designed to draw water from wells with depths up to 25 feet. Understanding the intricate details of each part is crucial for proper installation, maintenance, and troubleshooting. In this comprehensive guide, we’ll delve into the measurable and quantifiable aspects of the key components that make up a shallow well pump system.
The Pump: The Heart of the System
The pump is the central component of the shallow well system, responsible for drawing water from the well and delivering it to the user. Shallow well pumps are typically centrifugal pumps, which utilize a spinning impeller to create suction and push water up the suction pipe. The impeller’s diameter and the number of vanes directly impact the pump’s performance, with larger impellers and more vanes typically resulting in higher flow rates and greater lift capabilities.
Centrifugal pumps for shallow wells are available in a range of sizes, with horsepower ratings typically ranging from 1/2 HP to 2 HP. The pump’s flow rate is measured in gallons per minute (GPM) and can vary from 5 GPM to 20 GPM, depending on the pump’s size and the well’s depth. The pump’s inlet and outlet sizes are also crucial, with common sizes ranging from 1-1/4 inches to 2 inches in diameter.
The Suction Pipe: Connecting the Pump to the Well
The suction pipe is the conduit that connects the pump to the well, allowing the pump to draw water from the underground source. These pipes are typically made of PVC or steel, with PVC being the more common choice due to its corrosion resistance and ease of installation.
The size of the suction pipe is determined by the pump’s inlet size and the well’s depth. For shallow well pumps with a capacity of up to 5 GPM, a 1-1/4 inch suction pipe is commonly used. As the well depth increases or the pump’s capacity grows, the suction pipe size may need to be increased to 1-1/2 inches or 2 inches to minimize friction losses and ensure efficient water flow.
The suction pipe’s length is directly proportional to the well’s depth, with longer pipes required for deeper wells. It’s important to ensure that the suction pipe is properly sized and installed to prevent air leaks, which can lead to pump cavitation and reduced performance.
The Foot Valve: Preventing Backflow
The foot valve is a critical component located at the bottom of the suction pipe, just above the well’s water level. Its primary function is to prevent water from flowing back into the well when the pump is not in operation. This helps maintain the prime in the suction pipe, ensuring the pump can start up quickly and efficiently.
Foot valves are typically made of brass or stainless steel, with a screen or filter to prevent debris from entering the system. The valve’s size is matched to the suction pipe diameter, with common sizes ranging from 1-1/4 inches to 2 inches. The valve’s opening and closing mechanism is designed to create a tight seal, minimizing the risk of backflow and maintaining the system’s integrity.
The Check Valve: Protecting the Pump
The check valve is positioned between the pump and the pressure tank, serving as a one-way gate that allows water to flow in the desired direction while preventing backflow. This component is essential in maintaining the pressure tank’s charge and protecting the pump from the potentially damaging effects of reverse flow.
Check valves for shallow well pumps are typically made of brass or plastic, with a spring-loaded disc that opens and closes to allow water to flow in a single direction. The valve’s size is matched to the pump’s outlet diameter, with common sizes ranging from 1-1/4 inches to 2 inches.
The check valve’s performance is measured by its cracking pressure, which is the minimum pressure required to open the valve and allow water to flow. For shallow well pump applications, a cracking pressure of 5 to 10 PSI is typical, ensuring the valve opens promptly when the pump is in operation.
The Pressure Tank: Regulating Water Flow
The pressure tank is a crucial component in the shallow well pump system, serving to store water under pressure and regulate the flow of water to the user. Pressure tanks are typically made of steel or fiberglass, with an internal bladder that separates the water from the air.
The size of the pressure tank is determined by the pump’s capacity and the water demand of the user. For shallow well pumps with a capacity of up to 5 GPM, a 2-gallon pressure tank is commonly used. As the pump’s capacity or the water demand increases, the pressure tank size may need to be scaled up accordingly.
The pressure tank’s performance is measured by its pre-charge pressure, which is the air pressure maintained in the tank’s air chamber. This pre-charge pressure is typically set between 20 and 40 PSI, with the pump turning on when the pressure drops to the lower limit and turning off when the pressure reaches the upper limit.
The Pressure Switch: Controlling the Pump’s Operation
The pressure switch is the final component in the shallow well pump system, responsible for turning the pump on and off based on the pressure in the pressure tank. This switch is typically located near the pressure tank and has adjustable settings to control the pump’s activation and deactivation points.
For a shallow well pump system, a common pressure switch setting is 20/40 PSI. This means the pump will turn on when the pressure drops to 20 PSI and turn off when the pressure reaches 40 PSI. The pressure switch’s settings can be adjusted to match the specific requirements of the well and the user’s water demand.
The pressure switch’s performance is also measured by its electrical rating, which determines the maximum current and voltage it can handle. For shallow well pump applications, pressure switches with a rating of 30 amps or less are commonly used.
By understanding the measurable and quantifiable details of each component in a shallow well pump system, you can ensure proper installation, maintenance, and troubleshooting, ultimately providing a reliable and efficient water supply.
Reference:
- Well Pump, Parts, and Components Explained – YouTube
- Homemade Hydraulic Ram Pump for Livestock Water
- Pump Parts | Do it Best
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