YDK Foot Valve | Model: KF-16

The YDK Foot Valve Model KF-16 is a combination of a check valve and a strainer. This device helps retain the priming water column in the suction pipe while preventing mechanical contaminants such as waste, gravel, leaves, and other debris from entering the pump. This helps prevent the risk of motor damage and overheating in water supply pumping stations, fire protection pumping stations, and underground water tank suction systems.

Construction of YDK Foot Valve, Model KF-16

The YDK Foot Valve is typically installed at the lowest point, directly at the inlet end of the pump suction pipe, and submerged below the source water level (storage tank, well, pond, reservoir, etc.). The product essentially combines two functions in one device: a check valve that keeps the suction pipe filled with water for fast pump priming and prevents loss of pressure/dry running during restart; and a strainer that prevents debris, sediment, and organisms from entering the suction pipe and causing pump damage.

Construction table of 5 main components of the YDK KF-16 Foot Valve

YDK Foot Valve Dimensions

Detailed Operating Principle & Installation Position of YDK Foot Valve KF-16

Pump Operating Stage (Water Suction)

When the pump operates, it creates suction (a partial vacuum) in the suction pipe, causing the water pressure from the source to push the Disc upward away from the Disc Seat. Water passes through the gap between the disc and seat, flows through the foot valve body, and enters the pump through the suction pipe. At the same time, the Filter Screen surrounding the bottom prevents debris, sediment, and organisms from entering with the water flow.

Pump Shutdown Stage (Backflow Prevention)

As soon as the pump stops operating, the suction pressure disappears and gravity causes the Disc to drop down and make a tight seal against the Disc Seat, completely closing the valve opening. As a result:

• The entire water column in the suction pipe from the foot valve up to the pump is retained and does not flow back into the source.
• The pump remains in a “pre-primed” state for the next startup. Manual re-priming is not required, helping prevent dry running that could burn the mechanical seal or damage the pump impeller.

YDK Foot Valve Installation Position

• Position: Install at the far end of the suction pipe, fully submerged in the water source (storage tank, drilled well, pond/lake, underground fire protection tank, etc.).
• Minimum submergence: The bottom of the foot valve should be sufficiently far from the bottom of the tank/water source to prevent it from drawing in settled sediment, mud, or soil. A recommended minimum distance is 300 – 500 mm, depending on the valve size and pump flow rate.
• Submergence at minimum water level: The top of the foot valve must always remain below the lowest possible water level, including when the tank is nearly empty. Maintain a sufficient distance below the water surface to prevent air intake and vortex formation, which can cause vibration and reduce pump efficiency.
• Installation orientation: Always install vertically or nearly vertically, as the disc opens and closes by gravity. Horizontal installation is not recommended because the disc may not close tightly by itself when the pump stops.
• Clearance around the valve: Avoid placing the valve directly against the tank wall or in a corner. Sufficient clearance should be provided so that water can reach the filter screen from multiple directions, preventing local “water starvation” that could reduce suction flow.

Technical Notes When Selecting and Installing YDK Foot Valve

• Disc Seat tightness: This is the key factor determining the effectiveness of water priming retention. If the rubber seal becomes hardened, cracked, or contaminated with debris trapped between the disc and seat, the valve will not close completely, causing the water level in the suction pipe to gradually drop. This results in loss of pump prime and requires air release/re-priming each time the pump starts. This is one of the most common causes when customers report that the “pump does not deliver water” and the pump itself is not necessarily damaged.
• Ensure flange tightness: Use EPDM/NBR rubber gaskets compliant with BS4504 between the foot valve flange and suction pipe flange to prevent air leakage that could reduce suction pressure.
• Maintenance note: Because the foot valve remains continuously submerged in water and is directly exposed to sediment/debris, it should be regularly lifted out for inspection to check for a clogged strainer, worn disc seat, or trapped sediment.

If you are a customer, design consultant, or MEP contractor and require project-discount pricing or the YDK Model KF-16 Foot Valve catalogue, please contact An Phú Thành directly via Hotline/Zalo: 0946 729 913. Our experienced consulting team is always ready to assist you anytime, anywhere.