| Check Valve |
Allows flow in one direction and prevents reverse flow when the pump stops. |
Discharge piping, near the pump outlet, or in vertical risers. |
Protects the pump from reverse rotation, reduces backflow, and helps maintain system pressure. |
Water hammer, reverse flow, pressure loss, noisy operation, or a pump that rotates backward after shutdown. |
Inspect for debris, worn hinges, damaged discs, and restricted movement. Verify that the valve closes fully. |
Match the valve size, pressure rating, flow direction, connection type, and fluid compatibility. Select a low-cracking-pressure design when required. |
High |
| Foot Valve |
Maintains pump prime by preventing liquid from draining back through the suction line. |
At the end of a suction pipe inside a tank, well, or reservoir. |
Supports reliable priming and usually includes a strainer to keep large debris out of the pump. |
Loss of prime, extended startup time, air entering the suction line, or reduced inlet flow. |
Clean the strainer, inspect the sealing surface, check the hinge or spring, and test for backflow leakage. |
Confirm adequate submerged depth, correct suction-line diameter, compatible materials, and sufficient flow area to limit inlet restriction. |
High |
| Gate Valve |
Provides full-flow isolation by raising or lowering a gate across the pipeline. |
On suction or discharge piping where infrequent isolation is needed. |
Low pressure drop when fully open and suitable for isolation service. |
Stiff operation, incomplete shutoff, stem leakage, or reduced flow caused by a partially closed gate. |
Operate periodically, inspect the stem and packing, and check that the gate reaches the fully open or closed position. |
Do not use as a throttling valve. Match pressure class, end connections, bore size, and fluid temperature. |
Medium |
| Ball Valve |
Provides quick shutoff using a rotating ball with a drilled passage. |
Isolation points on pump suction, discharge, bypass, and utility lines. |
Fast operation, compact design, reliable shutoff, and relatively low flow resistance when open. |
Handle movement without flow change, leakage through the seat, difficult operation, or external stem leakage. |
Cycle the valve when permitted, inspect the stem seal, and remove deposits that may prevent full closure. |
Choose a full-port design where low pressure loss is important. Verify seat material, pressure rating, temperature range, and actuator requirements. |
Medium |
| Butterfly Valve |
Controls or isolates flow with a disc rotating around a central or offset shaft. |
Large-diameter suction, discharge, cooling-water, and process piping. |
Lightweight construction, compact installation, quick quarter-turn operation, and economical large-pipe service. |
Disc interference, seat leakage, excessive torque, vibration, or restricted flow when the disc is not correctly positioned. |
Inspect the disc and seat, verify shaft alignment, check actuator travel, and remove buildup from the sealing area. |
Confirm that the disc material is compatible with the fluid and that the valve can withstand the available pressure and temperature. |
Medium |
| Globe Valve |
Regulates flow by moving a plug toward or away from a stationary seat. |
Discharge-side control lines, bypass circuits, and applications requiring frequent throttling. |
Good control resolution and predictable throttling characteristics. |
Excessive pressure drop, noisy flow, seat erosion, packing leakage, or inability to regulate flow smoothly. |
Inspect the plug, seat, stem, and packing. Check for cavitation, vibration, and operation beyond the recommended travel range. |
Use a properly sized valve; an oversized valve may operate near its seat and provide unstable control. Verify trim compatibility with the fluid. |
High |
| Pressure-Relief Valve |
Automatically releases excess pressure to protect piping, equipment, and the pump system. |
Discharge headers, closed systems, pressure vessels, or pump bypass arrangements. |
Provides automatic overpressure protection without requiring operator action. |
Frequent lifting, leakage after opening, failure to open at the set pressure, or unstable pressure cycling. |
Test according to the system risk and applicable requirements. Keep the inlet and discharge paths clear and inspect for corrosion or deposits. |
Set pressure must remain within the protected equipment limits. Confirm capacity, discharge routing, fluid compatibility, and local code requirements. |
High |
| Pressure-Reducing Valve |
Reduces a higher upstream pressure to a controlled lower downstream pressure. |
Discharge branches, process-water lines, and pump systems serving lower-pressure equipment. |
Maintains a more consistent downstream pressure and protects sensitive components. |
Downstream pressure drift, chatter, low flow, excessive pressure loss, or inability to maintain the setpoint. |
Clean the strainer, inspect the diaphragm or piston, verify sensing passages, and confirm the downstream pressure setting. |
Size for the actual flow range rather than maximum pipe size alone. Check inlet pressure, outlet setpoint, temperature, and fluid cleanliness. |
High |
| Air-Release Valve |
Removes accumulated air from pressurized liquid piping during operation. |
High points in discharge piping, long pipelines, and elevated sections of pump systems. |
Reduces air pockets, improves hydraulic performance, and helps limit flow interruption and corrosion risk. |
Continuous air leakage, liquid discharge from the vent, trapped air, flow reduction, or repeated valve clogging. |
Inspect the float, vent mechanism, isolation arrangement, and internal screen. Remove sediment and verify the outlet is safely routed. |
Match the valve capacity to the expected air volume and operating pressure. Install at a true pipeline high point with suitable maintenance access. |
Medium |
| Control Valve |
Adjusts flow, pressure, level, or another process variable through manual or automatic actuation. |
Discharge control loops, bypass lines, dosing systems, and process branches. |
Enables precise process control and can respond automatically to changing operating conditions. |
Hunting, slow response, incorrect position feedback, excessive noise, cavitation, or failure to reach the commanded position. |
Check actuator travel, position feedback, instrument signals, packing, trim wear, and calibration. Inspect for vibration and abnormal differential pressure. |
Review the required flow coefficient, shutoff pressure, rangeability, actuator force, fail position, and cavitation or flashing risk. |
High |
| Suction Isolation Valve |
Isolates the pump from the suction source during maintenance or equipment removal. |
Immediately upstream of the pump inlet, where permitted by the system design. |
Allows safer pump servicing and helps separate equipment from the rest of the piping system. |
Restricted inlet flow, leakage when closed, excessive suction pressure loss, or inability to operate during an emergency. |
Keep fully open during normal pumping unless the system design specifically permits otherwise. Inspect operation, seals, and any lockout provisions. |
Select a full-bore or low-loss valve where possible. Verify that the valve does not create harmful suction restriction or increase cavitation risk. |
High |
| Drain Valve |
Allows liquid to be removed from the pump casing, piping, or low points for maintenance and winterization. |
At pump casings, low points, manifolds, and equipment drain connections. |
Supports safe draining, inspection, flushing, and protection against freezing or trapped pressure. |
Blocked drainage, leaking closure, seized handle, or unexpected liquid release during servicing. |
Operate periodically when safe, inspect the plug or ball and seal, and confirm that the drain outlet is directed to a suitable location. |
Use a valve rated for the fluid and pressure. Provide adequate access, isolation, and discharge containment before replacement. |
Medium |
