This procedure applies to Ocean Alexander yachts equipped with Headhunter Mach 5 freshwater pressure pumps. Performing this preventive maintenance every 6 months, or whenever a pump experiences nuisance alarms or excessive cycling, helps maintain consistent water pressure, improves pump performance, and extends system life.
Recommended Maintenance Interval #
- Every 6 months
- After extended vessel lay-up
- Following freshwater system repairs
- Anytime the pump alarms, loses prime, or cycles excessively
Required Tools #
- Tire pressure gauge
- Air compressor or hand pump
- Screwdrivers and basic hand tools
- Flashlight
- Replacement filter elements (if required)
Procedure #
1. Fill Fresh Water Tanks #
Verify the vessel’s freshwater tanks contain sufficient water before beginning maintenance.
2. Disconnect External Water Supply #
Disconnect any dockside water connection and ensure the vessel is operating solely from the onboard freshwater tanks.
3. Inspect the Accumulator Tank(s) #
Ocean Alexander yachts are typically equipped with one or more freshwater accumulator tanks.
- Remove the cap from the Schrader valve.
- Briefly depress the valve stem.
Normal: Air is released.
Fault: If water is discharged from the valve, the internal bladder has failed and the accumulator should be replaced.
4. Depressurize the System #
- Turn OFF all Mach 5 pumps.
- Open multiple faucets throughout the vessel (galley, heads, crew areas, flybridge, wet bar, etc.).
- Allow the system pressure to completely bleed off.
5. Check Accumulator Air Pressure #
With the plumbing fully depressurized:
- Measure accumulator pre-charge pressure.
- Adjust to 30–35 PSI.
- Replace any accumulator that will not maintain pressure.
6. Inspect the Pump Suction Side #
Before restarting the pumps, inspect:
- Suction strainers
- Filter housings
- O-rings
- Hose clamps
- Flexible hoses
- Isolation valves
Even a small air leak on the suction side can cause nuisance alarms, loss of prime, or dry-run faults. This is one of the most common causes of Mach 5 issues on larger yachts.
7. Purge Air from the Plumbing #
If the vessel has dual freshwater pumps:
- Start Pump #1 only.
- Leave several faucets open until a steady stream of water is produced.
- Repeat with Pump #2.
- Continue until all air has been removed from the plumbing.
8. Verify Pump Operation #
Close all faucets and allow the pumps to build pressure.
Confirm:
- Pump reaches shut-off pressure.
- No alarm indicators are present.
- Pumps stop normally.
- No rapid cycling occurs.
9. Inspect the System #
Walk the vessel and inspect:
- Machinery space
- Utility room
- Crew areas
- Galley
- Heads
- Exterior wet bars
- Flybridge
Check for leaks, drips, or unusual pump noise.
10. Return the Vessel to Service #
- Reinstall any removed filter elements.
- Restore normal pump configuration.
- Reconnect dock water if required.
- Verify stable operation before departure.
Common Ocean Alexander Findings #
During routine service, technicians frequently encounter:
- Low accumulator air pressure
- Air leaks at suction strainers or filter housings
- Loose hose clamps
- Dirty inlet strainers
- Waterlogged accumulator tanks
- Pumps that have lost prime after freshwater tank service
These conditions often cause intermittent alarms, excessive cycling, or reduced water pressure without indicating a failed pump.
Service Recommendation #
Ocean Alexander Service recommends incorporating this inspection into the vessel’s scheduled preventive maintenance program. Recording accumulator pressure, pump operating condition, and any corrective actions during each service visit provides a useful maintenance history and helps identify developing issues before they result in pump failures or loss of freshwater service.
Need Assistance?
For technical support, warranty assistance, parts, or to schedule service:
Ocean Alexander Yacht Service
East Coast Yacht Group
2955 W State Road 84 Fort Lauderdale FL, 33312
954-530-2033
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oayachtservice.com
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This article is part of the Ocean Alexander Yacht Service Knowledge Base. Information is provided for general guidance and should not replace the applicable Owner’s Manual or service procedures.
© Ocean Alexander Yacht Service – East Coast Yacht Group, Inc.
