Commissioning Your Marine Watermaker For Long-Haul Cruising

To annually commission your FCI marine water maker and prepare for the “long haul,” you should first check through the entire installation on the boat.

  1. Check the intake through-hull to make sure there are no obstructions.
  2. Make sure the seacock on the intake through-hull functions properly (that it opens and closes correctly).  This is often an overlooked issue. If the seacock is “frozen” in place, forcing movement can break it. Before the marine water maker is tested, make sure that the seacock is in the OPEN position.
  3. Make sure all feed water (and brine discharge) hoses are free of leaks and that all hose clamps are secure.
  4. Check the low pressure pump to ensure that the pump freely turns, that all electrical wiring is in good condition (no exposed wires, proper insulation, etc.), that the pump is properly fastened down, that there are no signs of leaks and that the low pressure pump seals are in good condition.
  5. Clear and clean debris from the sea strainer. Make sure that the sea strainer gasket is not brittle (if so, replace it). When re-assembling the sea strainer, the basket should be properly seated so that air does not leak in through the sea strainer (a proper vacuum is necessary).
  6. Renew/replace the prefilters on the marine water maker, and also make sure the seals on the prefilter housings are in good condition (again, they should not be brittle).
  7. Renew/replace the fresh water flush GAC filter (this should be done every 3-6 months on average).
  8. Test the fresh water flush line to make sure that the water from the fresh water tank reaches the water maker during the fresh water flush cycle. This assures that there were no valves that were inadvertently shut or that the line is somehow obstructed.
  9. Check the high-pressure pump on the water maker for leaks. If found, you might have to replace the high-pressure pump seals and/or valves.
  10. Be sure the high-pressure pump oil is fresh. Typically, high-pressure pump oil should be changed after the first 50 hours of system operation, and then after every 500 hours of usage.
  11. Check the brine discharge through-hull to make sure that there are no obstructions.
  12. Check the brine discharge seacock to make sure that it is functional AND that it is OPEN.  (Many people forget to make sure that it is OPEN, which causes damage to the water maker if the water maker is operated with a “closed off” brine discharge line.)
  13. Inspect the brine discharge hose to make sure that the hose is in good condition, that there are no leaks, and that the clamps are tight. (Also, there should be two hose clamps on the ends of each hose.)
  14. Now test the operation of the water maker. It is best to test the water maker in open ocean conditions where the seawater is exposed to good tidal exchange.
  15. Back the pressure regulator “off” all the way (turning it counter-clockwise as far as it will go).
  16. Start the low-pressure pump (only) on the system and let seawater circulate through the system for about 15 to 20 minutes.
  17. During this time, visually inspect the system, all components and all hoses to make sure that there are no leaks or other abnormalities. Confirm the feedwater inlet pressure is in the approximate range of 30 to 40 psi (depending upon the particular installation).
  18. After this period of time, gradually increase the system pressure (turning the pressure regulator clockwise) until the system is making its rated product water output. Confirm the system operating pressure, feedwater TDS, and system output.
  19. If the system comfortably makes its rated product water output, there is no further testing to do on the water maker. If the system is unable to make its rated output, then the user should call a service technician to conduct further testing on the membranes.
  20. Once the system testing is complete, turn the system “off” and wait 10 seconds to hear the system fresh water flush solenoid activate. The user will hear the fresh water flushing through the system. Once the fresh water flush is complete, the water maker is ready to use for the season.

If you’re planning some long-haul cruising, important spare parts to carry on board include prefilters, high-pressure pump oil, GAC filters, high and low-pressure pump seals and high-pressure pump valves. It is recommended to replace seals after every 1000 hours of use and valves after every 1500 hours of use.

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