Overview #
Ocean Alexander yachts utilize water check valves (also known as no return valves) throughout various onboard plumbing systems, including but not limited to:
- Bilge pump discharge systems.
- Raw water intake systems.
- Cooling water circuits.
- Plumbing discharge applications.
These valves are designed to allow water flow in one direction while preventing unwanted backflow. Proper operation of no return valves is essential for maintaining system reliability, preventing loss of prime, and ensuring proper operation of critical onboard equipment.
Routine inspection and preventative maintenance should be incorporated into the vessel’s maintenance schedule to ensure these components remain functional.
Understanding a No Return Valve #
A no return valve is a one-way valve that allows fluid to move through a system in the intended direction while preventing reverse flow.
In marine applications, these valves help:
- Prevent backflow into pumps.
- Maintain pump prime.
- Improve system efficiency.
- Protect equipment from reverse flow conditions.
A failed check valve can lead to:
- Bilge pump inefficiency.
- Loss of pump prime.
- Reduced water flow.
- Potential flooding concerns.
Types of Check Valves Commonly Used #
Swing Check Valve #
The most common marine check valve design is the swing check valve.
Operation:
- A hinged internal gate or disc opens when water flows in the correct direction.
- When flow reverses, the gate closes to prevent backflow.
Common materials include:
- Bronze body with metallic internal components.
- Plastic body with rubber sealing gates.
Loaded Ball Check Valve #
Another common design is the loaded ball check valve.
Operation:
- Fluid pressure pushes the ball away from the sealing surface.
- Water flows around the ball through the valve.
- Reverse pressure forces the ball closed, stopping backflow.
These are often used in applications where compact size and reliable sealing are required.
Common Check Valve Problems #
Check valves can experience issues due to:
- Debris entering the valve.
- Marine growth.
- Corrosion.
- Extended periods without operation.
- Internal component wear.
Common failures include:
Valve Stuck Open #
A valve stuck open may cause:
- Backflow.
- Loss of pump prime.
- Reduced system performance.
Valve Stuck Closed #
A valve stuck closed may cause:
- Restricted water flow.
- Pump overload.
- Failure of connected equipment.
Bilge Pump Check Valve Considerations #
Bilge pump check valves require special attention because they are often:
- Used infrequently.
- Located in areas where debris may collect.
- Critical to vessel safety.
A malfunctioning bilge check valve can contribute to:
- Improper bilge evacuation.
- Reduced pump performance.
- Increased risk during flooding events.
Ensure valves remain accessible for inspection and cleaning.
Preventative Maintenance Procedure #
Inspection Frequency #
Recommended inspection:
- Monthly during normal operation.
- Before extended cruising.
- After long passages.
- During routine bilge system inspections.
Cleaning Procedure #
- Isolate the system and ensure the pump cannot operate unexpectedly.
- Remove the valve if serviceable.
- Disassemble according to manufacturer recommendations.
- Rinse components with fresh water.
- Remove buildup using a soft-bristle brush.
- Inspect internal components.
- Reassemble and verify proper operation.
Lubrication #
For applicable bronze valves:
- Apply approved anti-seize or marine-compatible lubricant to threaded components.
- Ensure moving components operate freely.
- Prevent corrosion and simplify future servicing.
Do not apply lubricants that may contaminate potable water systems.
Inspection Checklist #
Inspect for:
☐ Cracks or physical damage
☐ Corrosion
☐ Deformed components
☐ Restricted movement
☐ Debris or marine growth
☐ Proper sealing
☐ Tight hose clamps and fittings
Any valve showing damage, excessive wear, or unreliable operation should be replaced.
Functional Testing #
After inspection:
- Operate the connected pump or system.
- Confirm proper flow direction.
- Verify the valve opens during operation.
- Confirm the valve closes and prevents backflow.
A properly functioning valve should operate smoothly without sticking or hesitation.
Replacement Guidelines #
Depending on material, environment, and operating conditions:
- Inspect valves regularly for deterioration.
- Replace valves showing wear or unreliable operation.
- Typical service life may be approximately 5–7 years, depending on application and condition.
Always replace with the correct valve type and size specified for the system.
Frequently Asked Questions #
Why does my pump lose prime? #
A failed or stuck-open check valve may allow water to drain back through the system, causing the pump to lose prime.
Can I operate without a check valve? #
No. Removing a required check valve may negatively affect system operation and can create safety concerns, especially in bilge and raw-water applications.
Why does my pump run but move little or no water? #
Possible causes include:
- Check valve stuck closed.
- Debris restriction.
- Air entering the system.
- Failed pump.
- Blocked intake or discharge line.
Crew Reminder #
No return valves are small but critical components of the vessel’s plumbing and safety systems. Regular inspection, cleaning, and functional testing help ensure reliable operation of bilge, raw water, and other onboard systems.
This guide is intended as a supplemental Ocean Alexander Knowledge Base reference and does not replace manufacturer instructions or vessel-specific maintenance procedures.
East Coast Yacht Group
2955 West State Road 84
Fort Lauderdale, FL 33312
Service Department
954.530.2033
Contact our Service Department today to learn how we can help ensure safe and peak performance for your vessel.
